SkySafari Manual

This section contains a copy of the SkySafari manual. This manual is also included with the SkySafari app, under the Help section. Sometimes it's convenient to have the manual on a separate screen while you're using the app, so we've included it here as well.

This manual applies to all three versions of SkySafari 3 - basic, Plus, and Pro. The manual notes where the versions differ. Some features are only present in SkySafari Plus and Pro.

Sky Chart & Toolbar

This section describes the main Sky Chart window, and the functions of the main toolbar buttons below it. The Scope button (for telescope control) is only present in SkySafari Plus and Pro, and is described under the Scope Control section below.

Settings

A detailed guide to the many settings screens available in SkySafari. All of these settings are available under the Settings button in the main toolbar.

Scope Control

This section describes the user interface for the telescope control feature of SkySafari Plus and Pro. The Scope Control view is available in the main toolbar; the telescope communication and display settings are located in the Settings view.

Settings Files & Observing Lists

This section describes the types of files that you can generate with SkySafari. Settings files are saved and restored in the Settings view. Observing lists, found only in SkySafari Plus and Pro, are created under the Search view.


The constellations Sagittarius and Scorpius (highlited), shown by SkySafari
as mythical figures, near the center of the Milky Way.

Introduction

SkySafari is a celestial travel guide, designed to help you explore the night sky. It is a powerful planetarium program that fits in your pocket, with thousands of stars, planets, and other objects at your fingertips. And SkySafari's Plus and Pro versions can turn your iPhone, iPad, or iPod Touch into a 21st-century telescope controller.

SkySafari contains a database with hundreds of thousands - or millions - of stars. It displays the planets and moons of the Solar System using NASA spacecraft imagery, and includes hundreds - or thousands - of asteroids, comets, and artificial satellites.

SkySafari is able to accurately depict these objects in the sky from any location on Earth, and at any time in the past, present, or future. In addition, SkySafari includes informative, plain-English descriptions of the constellations, planets, moons, stars, and deep sky objects. It contains hundreds of images from NASA space missions, the Hubble Space Telescope, and the world's foremost amateur and professional astro-photographers.

SkySafari now includes push notifications. With these, you can automatically receive notifications of celestial events, like eclipses and transits, discoveries of new comets, supernovae, or other product-related announcements.

SkySafari supports Apple's iPad VGA adapter. With this adapter connected, your iPad can mirror SkySafari's displays on an external monitor - or a big-screen TV!

SkySafari's simple user interface, combined with its ability to control your GoTo telescope, makes it an invaluable tool for exploring the night sky. We hope you enjoy using SkySafari.

The Moon passes through the Pleiades star cluster (M 45),
showing data and images from SkySafari Plus.

SkySafari Plus and Pro

SkySafari comes in three versions:

SkySafari's basic version contains 120,000 stars to 8th magnitude, and the 220 best-known star clusters, nebulae, and galaxies in the sky (the Messier and Caldwell catalogs). It includes images of most Messier objects, and nearly 500 object descriptions.

SkySafari Plus includes 2.5 million stars to 12th magnitude, and 30,000 deep sky objects, including the entire NGC and IC catalogs. SkySafari Plus also contains more than 300 color images of the best known nebulae and galaxies from the Digitized Sky Survey, and more than 1000 object descriptions.

SkySafari Plus can also point your computer-controlled GoTo telescope anywhere in the sky. To do this, you'll need either our SkyWire serial cable accessory, or a Wi-Fi-to-serial adapter like our SkyFi or Orion's StarSeek Wi-Fi adapter. See the Southern Stars website for more details.

SkySafari Plus also offers higher precision, more sky charting options, the ability to update asteroid/comet/spacecraft data from the internet, observation planning and logging capabilites, and other features of interest to serious observers.

SkySafari Pro contains the same features and functions as SkySafari Plus. But it adds a vastly-expanded database of 15 million stars to 15th magnitude from the Hubble Guide Star Catalog; a deep sky database of 740,000 objects to 18th magnitude from the Principal Galaxy Catalog; and a solar system database of over 550,000 objects - including every known planet, moon, asteroid, and comet.


The Sky Chart view, looking northwest.
Note the - and + hot corners for zooming,
and Deneb as the selected object.
Click to enlarge.

The Sky Chart

The Sky Chart view is the primary screen of SkySafari. It consists of the Time and Location bar at the top, the main Sky Chart in the middle, and a Toolbar along the bottom.

The first time your run SkySafari, the program will ask if you want to retrieve your current location using the GPS or network location capabilities built into your iPhone or iPod. You can always change these settings later, using the main Settings view.

Status Bar: This bar displays the current date, time and location used by the application to depict the night sky. These values may be changed using the Settings view.

Toolbar: The tool bar contains buttons to bring up the other secondary views used by SkySafari. These include Search, Object Info, Settings, Time Flow, Scope Control, and Help.

Sky Chart: The sky chart shows an accurate depiction of the sky. The information displayed is highly configurable, and may be changed in the SkySafari Settings views. The sky chart shows the location of the stars, planets, and deep sky objects (star clusters, nebulae, and galaxies) as seen from your date, time, and location.

If you rotate your iPhone or iPod Touch to Landscape mode (i.e. "sideways"), SkySafari hides the toolbar and status bar to give you a full-screen view of the sky. You can show the on-screen controls again by rotating your device to Portrait mode. On the iPad, with its larger screen, SkySafari always shows the toolbar and status bar. You can change this behavior in the Auto-Rotation section of the Appearance settings.

Navigating the Sky Chart

The part of the sky that is currently under the earth is shown with a green background. The horizon, which divides the earth from the sky, is shown as a bright green line, with the cardinal directions (east, northeast, north, etc.) marked. Note: if the sky chart is using Equatorial coordinates (see Settings > Coordinates) the horizon will not be shown.

Touch the chart and drag to change the direction you are looking in the sky. Use the standard two-finger pinch gesture to change the field of view shown in the chart. You can zoom the field of view from 180 degrees, showing you the whole sky at once, down to 0.1 arcminutes - about the average size of Mars as seen from Earth.

You can also zoom in or out by touching and holding your finger down in the lower right or left corners of the sky chart. When swiping or pinching the chart with your fingers, a + and - sign will appear. These show you where to touch and hold in order to zoom in or out.

As you drag or zoom the chart, the current coordinates of the chart's center, and the width and height of the field of view, are displayed at the top of the chart. You can turn this feature on or off using the Show While Changing Chart settings in the Settings > Coordinates view of SkySafari Plus and Pro (or Settings > Field of View in SkySafari's basic version).

Tap an object on-screen to select it. If there are multiple objects next to each other and the first tap selects the wrong object, tap again and SkySafari will select an alternate object nearby. Once you have selected an object, double-tap it to bring up the Object Info view. The Object Info view shows numerical data for the object, as well as English-language descriptions and images for many of the brighter objects in the sky.

Using the Compass and Accelerometer

If you have an iPhone or iPad with a compass, SkySafari can show you the sky in same the direction that you're holding your phone. To activate the compass and/or accelerometer, shake the phone. SkySafari now draws the sky chart in the direction you're holding your phone, and continually redraws the chart as you move the phone around. Now you can identify stars and planets by holding your phone up to them! Tap an object on the screen to select an object and display its name. Touching the screen turns off the compass and accelerometer; shake the phone to activate them again.

To find a specific object in the sky using your phone's compass and accelerometer, first shake the phone to activate them. Then tap the Search button in the toolbar, and enter the object's name (like "Jupiter"), or select it from the list of common objects (like Planets). The Object Info window appears, providing information about the object. Tap the Center button at the bottom of the Object Info window. An arrow appears over the sky chart, leading you toward the selected object. Move your phone in the direction of the arrow to center the object in the field of view. When the object is centered, the arrow disappears, and your phone will be pointing toward the object in the sky.


The Search view lets you search for objects by name,
choose objects from lists, and - in SkySafari
Plus and Pro - create custom lists
of objects to observe. Click to enlarge.

Search

The search view lets you search for objects, by typing their names, or by choosing them from lists. In SkySafari Plus and Pro, the Search view also lets you manage observing lists, which are lists of objects that you can create and edit yourself. Observing lists help you plan your observing sessions, and record logs of your observations.

Search

At the top of the list view is a search field. Enter all or part of an object's name; then tap the Search button to display a list of matching objects. For example, if you search for "Saturn", SkySafari will find both the planet Saturn and the Saturn Nebula.

You can search for an object using any of its catalog designations. For example, the Andromeda Galaxy can be found as M31, NGC 224, UGC 454, PGC 2557, MCG 7-2-16 or CGCG 535-17. Likewise, the double star Porrima can be found as Gamma Virginis, 29 Vir, HR 4826, SAO 138917, BD -00 2601, HIP 61941, STF 1670, ADS 8630 or WDS 12417-0127.

All of the objects matching your search will be displayed in the list of results. Objects below the horizon are dimmed, but still selectable.

Choose a specific object from that list to bring up the Object Info view for that object. If there is only one object which matches the name you entered, the Object Info will be shown immediately, without a list of search results (since that list would contain only one item!)

Common Object Lists

This section contains lists of the most commonly-known objects in the sky (e.g. planets, stars, deep sky objects, etc). Choose a list to display the most commonly-known objects in that category. For example, the Planets list shows the nine planets (we still include Pluto even if the International Astronomical Union doesn't); the Brightest Stars list shows the brightest stars in the sky; the Messier Objects list shows the most famous 110 star clusters, nebulae, and galaxies in the sky, etc.

Objects currently above the horizon are listed with a brighter text color; objects below the horizon are dimmed, but you can still select them. Choose a specific object from this list to bring up the Object Info view. This view displays basic information about the object, and contains buttons to center it in the sky chart or in your telescope's field of view.

Tonight's Best is a list of the best objects that will be visible between tonight's dusk and tomorrow's dawn. The objects in this list change depending on your location, and on the date. An object must reach at least six degrees above the horizon between astronomical dusk and dawn to be included in this list.

In SkySafari's basic version, Tonight's Best list includes only brightest stars and planets visible to the naked eye, and the brightest and best-known deep sky objects that can be seen with a pair of binoculars. SkySafari Plus and Pro add the best double and variable stars, star clusters, nebulae, and galaxies visible in small backyard telescopes. A few objects of extreme astrophysical or historical importance are also in the list, even if they're difficult or impossible to see in a backyard telescope - like Barnard's Star, Halley's Comet (at least until 2061), and Eris - the "dwarf planet" which dethroned Pluto as the solar system's outermost planet.

Objects in the list are sorted by their transit times, giving you a natural order in which to observe them. If you are viewing Tonight's Best list during daylight hours, many objects toward the end of the list may not have risen yet, and so are dimmed in the list. Similarly, if you are viewing Tonight's Best list in the early hours before dawn, objects near the start of the list may have already set, and so are also dimmed.

Custom Observing Lists

Custom observing lists keep track of objects you want to observe, and record logs of your observations. By default, SkySafari comes with a single, empty observing list called "My Favorites". To create additional lists, tap the Create New Observing List button at the bottom of the Search view.

Please Note: this feature is only available in SkySafari Plus and Pro. For more information on observing lists, see the Observing Lists help section.


The Object Info view presents numerical data and English-language
descriptions for any object or constellation you have selected
in the sky chart. It lets you center the object in the sky chart,
and (in the full version of SkySafari) GoTo or Align on that object
with a telescope. Click to enlarge.

Object Info

The Object Info view shows a variety of information about the selected object. The exact information displayed depends upon the type of object you have selected (e.g. a star, planet, deep sky object, etc).

The Object Info view has a button along the bottom to Center the object in the sky chart. There is also a Description button, which shows an English-language description, along with images, for several hundred of the brightest and best-known stars and deep sky objects. If your selected object has no description, this Description button not appear. On the iPad, descriptions for objects which have them will appear alongside the object's numerical data.

If you are using your device's gyroscope or compass/altimeter, then tapping the Center button will not center the selected object directly. Instead, an arrow appears, leading you toward the selected object. Move your phone in the direction of the arrow to center the object in the field of view. When the object is centered, the arrow disappears, and your phone will be pointing toward the object's position in the sky.

Please Note: for best results with the compass, turn your phone sideways to landscape mode.

If you have connected with a GoTo telescope using our SkyWire accessory or your iPhone or iPod's Wi-Fi capability, additional buttons appear to let you GoTo the object with your telescope, or to Align your telescope on the object. See the Scope Control view for more information about this.

At a minimum, SkySafari displays the following information for the object:

  

The Object Info view contains English-language descriptions of objects and constellations, like Orion (left).
Tap any link in the description to show a full-screen image, such as the Orion Nebula (right).

Add Object to Observing List: Tap this button to add the object to an observing list. If you only have one observing list, the object will be added to that list. If you have more than one list, SkySafari will let you choose which list you want to add the object to. Yes, I have just ended a sentence with a preposition!

Please Note: This feature is only available in SkySafari Plus and Pro.


Center

The Center button centers the selected object in the sky chart. Use this button if the selected object has moved off screen, and you want to re-center it in the field of view. The selected object will stay centered if you zoom in or out, or animate the sky chart using the Time Flow controls.

If you are using your device's gyroscope or compass/altimeter, then tapping the Center button will not center the selected object directly. Instead, an arrow appears, leading you toward the selected object. Move your phone in the direction of the arrow to center the object in the field of view. When the object is centered, the arrow disappears, and your phone will be pointing toward the object's position in the sky.

Please Note: for best results with the compass, turn your phone sideways to landscape mode.

The Settings > Chart Animations switch provides animated panning to objects that you select and center in the sky chart. If turned off, the chart jumps instantly to objects when you center them. Please Note: this feature is only available in the SkySafari Plus and Pro.


Settings

A detailed guide to the many settings screens available in SkySafari. All of these settings are available under the Settings button in the main toolbar.


Using Time Flow to animate the motion of Saturn's
moons at one minute per step.

Time Flow

The Time button in the main Sky Chart toolbar displays a set controls which let you flow the date and time dynamically, or adjust it step-by-step. Tap the Time button to show these controls; tap it again to hide them.

When visible, the time flow controls contain the following items:

Time Units: a row of buttons directly above the main toolbar lets you select the time unit you wish to change. Tap "Sec" to change the seconds, "Day" to change the day, "Year" to change the year, and so on.

Time Flow Arrows: Above the time units, a set of VCR controls lets you start and stop the flow of time. Tap the rightmost arrow to start the flow of time continuously forward; tap the leftmost arrow to flow time continuously backward. Tap either of these arrows to stop the flow of time.

Time Step Arrows: The central arrows adjust the time by a single step, equal to the time unit you have selected underneath. For example, if you selected 1 day as the time unit, tapping the center right arrow will move the time forward by 1 day - but it will not continuously run the time by one day.

Now Button: Stops the flow of time, and returns to the current date and time indicated by your iPhone or iPod's internal clock.

You'll find that different astronomical phenomena are best simulated using different time units. For example:

Time flow is temporarily paused when another view (like Search, Object Info, or Settings) is present. You can also use the Settings to change the simulated date and time. If you are using SkySafari to control a telescope, we do not recommend using Time Flow while the telescope is connected - simulating a view other than the current date and time may result in pointing the telescope at the wrong place in the sky!


Compass Help

If you have an iPhone/iPad with a compass, SkySafari can show you the sky in same the direction that you're holding your phone. As you move the phone around, the view on the sky chart follows your motion. You can identify stars and planets by holding your phone up next to them, and you can find any object in the sky by following an arrow that points in its direction.

You can activate the compass in two ways:

Tap the Compass button again, shake the phone again, or touch any part of the sky chart, to turn the compass off. You can enable or disable the "shake to use" compass/altimeter feature in the Settings > Field screen in SkySafari (or the Settings > Coordinates view in SkySafari Plus and Pro.) You can turn off "Shake to Use" if you find that you're accidentally activating the compass/altimeter too often, or if you prefer to activate them from the main toolbar.

Please note: you need an iPhone 3GS, iPhone 4, or iPad to use the compass; earlier devices do not have one. The toolbar icon for the Compass will not appear if you're running SkySafari on a device that lacks one. If your device has both a compass and a gyroscope, you can't use them both at the same time: if you turn on the compass, the gyroscope turns off, and vice-versa.

Using the Compass

SkySafari uses the compass and altimeter to center the sky chart on the direction you're holding your phone. You can also use them to find objects in the sky. To do this, first turn on the compass/altimeter. Then use the Search view to select the object you are looking for. When the Object Info view appears, tap the Center button at the bottom of view. An arrow appears, leading you toward the selected object. Follow the arrow with your phone to center the object in the field of view. When the object is centered, the arrow disappears, and your phone will be pointing toward the object's position in the sky.

Please Note: for best results with the compass, turn your phone sideways to landscape mode. In SkySafari Plus and Pro, the compass and altimeter will be turned off if you connect to a telescope, or lock on the telescope's position in the sky chart. The sky chart cannot be centered on the telescope's position, and centered on the coordinates reported by the compass/altimeter, at the same time.

A note on accuracy: the solid-state compass built into the iPhone/iPad is not very accurate, and easily affected by interference. It can easily be wrong by ten degrees or more. The compass may be useful for locating bright objects in a general part of the sky, but it's certainly not accurate enough to point a telescope - and definitely not a substitute for the Celestron SkyScout.


Gyro Help

If you have an iPhone 4 or iPod Touch with a gyroscope, SkySafari can show you the sky in same the direction that you're holding your phone. As you move the phone around, the view on the sky chart follows your motion. You can identify stars and planets by holding your phone up next to them, and you can find any object in the sky by following an arrow that points in its direction.

You can activate the gyroscope by tapping the Gyro button in the toolbar. Tap the Gyro button again, or touch any part of the sky chart, to turn the gyroscope off.

Please note: you need an iPhone 4 or a 4th-generation iPod Touch to use the gyroscope. The toolbar icon for the Gyro will not appear if you're running SkySafari on a device that lacks one. If your device has both a compass and a gyroscope, you can't use them both at the same time: if you turn on the compass, the gyroscope turns off, and vice-versa.

Using the Gyro

Unlike the compass/accelerometer, the gyroscope measures your device's orientation relative to a known starting point. The gyro does not measure your device's true orientation relative to north/south/east/west or up/down in the sky. So to find your way around the sky with the gyroscope, you'll need to use a slightly different process.

First, locate a known reference object in the sky, like the Moon, or the Big Dipper. Then search for the same object in SkySafari, and center it on the screen. With the object centered, hold your device toward the object in the sky. Then tap the gyro button (with a finger in your other hand!) to turn on the gyro. Now, as you move your device around, the gyroscope follows its orientation relative to the object you used as a starting point. As you move the device around, the sky chart on the screen follows to match the view in the sky behind it.

As with the compass, you can use the gyroscope to find an object in the sky. Start with a known object in the sky, then find and center the same known object in SkySafari's sky chart, and turn on the gyroscope - just as described above. Then search for the unknown object you're trying to find in SkySafari. When the Object Info view appears for that object, tap the Center button. SkySafari show an arrow that leads toward the object; follow the arrow with your phone to find the object in the sky.

Although the gyroscope requires you to begin with a known object as a starting point, its motion is generally much smoother and more accurate than the compass. And on devices which lack a compass - like the 4th-generation iPod Touch - it's really the only option for finding objects in the sky.


Night Vision Help

The Night button changes SkySafari's appearance to a red-on-black theme designed to help preserve your night vision. The Night Vision theme is best used in the dark, out under the stars. Tap this button once to switch to the Night Vision theme; tap again to restore SkySafari to its previous appearance.

You can switch to and from Night Vision in two ways:

For many people, the screen is still too bright to effectively preserve their night vision - even when SkySafari is using its Night Vision theme. If this is true for you, SkySafari has a Screen Brightness setting (also found in the Settings > Appearance view) which lets you adjust the screen brightness. However, this setting only works within SkySafari. To turn down the screen brightness for all apps on your devices, use the screen brightness slider in the main Settings app on your device.

An even better solution is to place a piece of red film over the screen. A brand called Rubylith seems to work particularly well for this purpose. A "hardware" approach to preserving your night vision works better than any software solution because it will enforce a red appearance across all applications, not just SkySafari.

  

The Scope Control view, looking at the Orion Nebula (M42) in "normal" mode (left) and Night Vision mode (right).
Tap the Night button on the toolbar to engage or disengage Night Vision. Click to enlarge.


SkyWeek Help

Southern Stars and the editors of Sky & Telescope magazine have collaborated to bring you SkyWeek - the interactive mobile version of S&T's super-popular "This Week's Sky at a Glance" web page - as an integrated feature in SkySafari version 3! "This Week's Sky at a Glance" has been Sky & Telescope's most popular online offering for 21 years, and SkyWeek gives you a day-by-day calendar of events to observe in the changing night sky.

SkyWeek describes all major sky events: eclipses, conjunctions, good meteor showers - miss nothing! Whether you're a newbie skywatcher or an experienced amateur astronomer, SkyWeek will become your handy, everyday guide to what's up.

Tap the SkyWeek icon in SkySafari's toolbar to view a page listing the week's current events. Tap the VIEW icon next to a particular event to view a custom sky map which illustrates the event. Sky maps that are automatically set for your location. And starting from the sky scene that's displayed, you can pan around the heavens, change the scene to other times and dates, and zoom in or out.

SkyWeek's daily event listing also includes links to more info. Content on Sky & Telescope's web site may require a user account login and password. If you have a Sky & Telescope web site account, simply enter it when prompted. Otherwise, you can create and register a new Sky & Telescope account; registration is free. You will only have to log in or register once; SkySafari remembers your user name and password for future logins.

  

SkyWeek gives you descriptions of events to observe every night of the week,
and simplified star charts to illustrate each event. Click to enlarge.


Date & Time

The Date & Time view can be set to use the current time, or can be set to a specific time/date in the past or future. When set to current time, the chart view will update every second to show the current positions of objects in the sky.

To set the date and time to a specific time, first turn Use Current Time off. To change the Date, touch the Date | Time bar to highlight Date. Rotate the picker wheels to the desired date. To change the time, touch the Date | Time bar to highlight Time. Rotate the picker wheels to the desired time. There are buttons below the picker to allow you to quickly set the time to specific important times such as Sunset, Moonset, etc.

  

The Date & Time settings let you select an exact moment in time to simulate the night sky. Click to enlarge.

When the Date picker is visible, there is a switch that turns automatic daylight savings time (DST) correction on and off. When the switch is on, SkySafari automatically determines whether DST is currently in effect based upon your location and the date, and it displays a DST status message below the switch. In the rare case where the rule doesn't work, you may turn automatic DST off and instead add one hour to your Time Zone setting in the Location view.

In SkySafari Plus and Pro, the Local Sidereal Time is displayed near the bottom of the Date settings view. This indicates the hour of right ascension that is currently on your local meridian, and is sometimes used for aligning a telescope. SkySafari's basic version does not display the local sidereal time.


The Location settings let you set your observing location -
by using your iPhone's GPS, choosing from a
list of cities, or precisely entering a latitude
and longitude. Click to enlarge.

Location

SkySafari needs to know your location on Earth in order to correctly plot the location of objects in the sky. You can set this in the Location view from the main Settings screen. Four pieces of information are necessary:

There are three ways to set this information:

Use Current Location: Tap the "Use Current Location" button to use the iPhone's Location Manager to automatically determine your location based upon GPS or other information supplied by your internet service. When the location information is obtained this way the location name is filled in as "Current Location".

Choose Location From List: If you are near a major city, you can choose your location from a list. Tap "Pick from List" to see a list of countries or geographic areas. Choosing an area shows a list of major cities in that area. Choosing a city will automatically fill in the data for you.

Manual Entry: Finally, the information can be entered manually. A service like Google Earth can provide your latitude, longitude and elevation, if not known. Time zone offset information is available at http://wwp.greenwichmeantime.com/. A time zone offset behind or west of GMT is expressed as a negative number; one that is ahead or east of GMT is expressed as a positive number.

When entering a time zone offset from GMT, always enter the offset for Standard Time only. SkySafari will automatically correct this for Daylight Savings Time if DST is currently in effect (and the appropriate switch in the Date & Time view is turned on). Don't enter a Daylight Savings Time GMT offset here.

Save User-Defined Location: Tap the "Save User-Defined Location" to store a manually-entered location for retrieval later. To retrieve a user-defined location, tap the "Choose Location from List" button, then choose the "User-Defined Locations" group. You must name your location something other than "Current Location" before saving it as user-defined. If you choose the same name as an existing user-defined location, that existing location will be overwritten with the new longitude, latitude, etc. currently displayed in the Location view.

You can delete user-defined locations as follows:

  1. Tap the "Choose Location from List" button. Choose the "User Defined Locations" group at the end of the location groups list.
  2. Tap the "Edit" button at the top of the user-defined locations list.
  3. Tap the small, red, round, "-" button for each user-defined location you wish to delete. Confirm by tapping the red "Delete" button that appears to the right.
  4. When you are finished, tap the "Done" button at the top of the user-defined locations list.

Please Note: the User-Defined Location feature only available in SkySafari Plus and Pro.


The Coordinates settings let you precisely set the field of view. Click to enlarge.

Coordinates

The settings in this view let you select the coordinate system used to display the sky chart, and precisely center the chart on a particular set of coordinates. You can also set the field of view width and orientation, and display or hide the chart center coordinates and field of view while you are swiping or pinching the chart.

Coordinate System

This sets the coordinate system used by SkySafari. There are two options that you can choose here:

When using Equatorial coordinates, the horizon is not visible in the sky chart.

Chart Center Coordinates

Center Azm (or RA): Sets the azimuth at the center of the sky chart. North is 0°, East is 90°, South is 180° and West is 270°. You may enter a new azimuth to precisely set the chart's center.

Center Alt (or Dec): Sets the altitude at the center of the sky chart. At 0° the chart is centered on the horizon, at +90° it is centered directly overhead at the zenith, and at -90° it is centered directly under your feet.

When using Equatorial coordinates, the chart center RA and Dec are always assumed to be for the precession epoch specified in the Precession settings.

When using Horizon coordinates, the chart center altitude is assumed to be apparent (i.e. it includes the effects of atmospheric refraction) if the Refraction option is turned on in the Precession settings. If this option is turned off, the chart center altitude is assumed to be the true (un-refracted) altitude.

Field of View

Field Width Angle: Sets the sky chart's field of view width angle using a slider control.

The largest field of view SkySafari can display is 180 degrees, letting you see the entire sky at once. As the field of view increases past 90 degrees, the horizon becomes curved, due to the distortion caused by projecting the entire celestial sphere onto the flat iPhone screen.

If you hold your iPhone at arm's length, about 2 feet from your eyes, its 2-by-3 inch screen has an apparent size of 4.8 by 7.2 degrees. So, if you set the field of view width to 4.8 degrees (portrait mode) or 7.2 degrees (landscape mode), and hold your iPhone out at arm's length, the view on your iPhone should appear at the same scale as the real sky.

The smallest field of view SkySafari can display is 0.1 arcminutes, or 6 arcseconds - about the average size of the planet Mars as seen from Earth. One arcsecond is the best resolution a typical 8" backyard telescope can achieve under good observing conditions.

For comparison, the Sun and Moon appear about 1/2 degree (or 30 arcminutes) across. The smallest angle the unaided human eye can resolve is about 1/30th of a degree, or 2 arcminutes - about 1/15th the width of the full Moon. At its closest approach to Earth, the planet Venus appears about 1 arcminute across; Jupiter typically appears appears 45 arcseconds across.

Flip Horizontally: "On" flips the sky chart display horizontally to match the view in a telescope whose optical design results in a mirror-image view.

Flip Vertically: "On" flips the sky chart display vertically to match the view in a telescope whose optical design results in an upside-down view.

Compass and Accelerometer

SkySafari can use the compass and altimeter built into your device to center the sky chart on the direction you're holding your phone. If your device does not have a compass, this option is disabled.

Shake to Use: When turned on, you can shake your iPhone or iPod Touch to activate the compass and/or altimeter. One quick shake will do it! Once activated this way, touch the screen anywhere to turn the compass/altimeter off. Turn "Shake to Use" off if you find that you're accidentally activating the compass/altimeter too often, or if you prefer to activate them from the main toolbar.

Please Note: for best results with the compass, turn your phone sideways to landscape mode. Also, the compass and altimeter will be turned off if you connect to a telescope, or lock on the telescope's position in the sky chart. The sky chart cannot be centered on the telescope's position, and centered on the coordinates reported by the compass/altimeter, at the same time. See the Scope Control view Help page for more information.

When the compass/altimeter have been activated by shaking, the coordinate system will change to Horizon coordinates (see above).

On Screen Display

This items in this section control how the chart center coordinates and field of view are displayed at the top of the sky chart.

Show Always: When turned on, the chart center coordinates and/or field of view are always displayed at the top of the sky chart. When turned off, these items are only displayed when you swipe or zoom the chart, and will fade after you remove your finger from the screen.

Field Width x Height: Sets whether the sky chart's field of view is shown in the upper right while changing the field of view.

Center Coordinates: Sets whether the coordinates at the center of the sky chart are shown in the upper left while changing the field of view.


The Precession settings, found only in the full version of SkySafari,
give you precise control over the corrections SkySafari makes when
computing the positions of objects in the sky.

Precession

The settings in this view lets you set the precession epoch of the Equatorial coordinate system that SkySafari uses to report the right ascensions and declinations of objects. It also give you precise control over the corrections SkySafari makes when computing the positions of objects in the sky.

Precession & Nutation

Precession is a very slow "wobble" in the direction of the Earth's rotational axis, which takes about 25,800 years to complete. The Earth's axis defines both the Equatorial (or RA-Dec) coordinate system. Because of precession, an object's right ascension and declination change over time - not because the object is moving, but because the coordinate system is moving.

Use Current Epoch: if turned on, SkySafari will always report right ascensions and declinations for the current year ("epoch"). If turned off, SkySafari will report RA and Dec for the precession epoch entered below.

Precession Epoch: the precession epoch (or year) for which equatorial coordinates should be reported, if "Use Current Epoch" is turned off. Star atlases and ephemeris predictions (e.g. as in the Astronomical Almanac) often use a fixed epoch, such as 2000.0, for reporting RA and Dec.

Include Nutation: a small wobble in the orientation of the Earth's axis superimposed on its overall precessional motion. Nutation causes a small change in an object's position, typically amounting to about 8-10 arc seconds.

Other Corrections

Aberration: a systematic shift in star positions caused by the Earth's velocity through space. It is a result of Einstein's theory of special relativity. Aberration causes objects to appear to shift in the direction that the Earth is moving by about 20 arc seconds, and affects all objects in the same part of the sky equally.

Proper Motion: a slow change in the positions of the stars due to their physical motion through space. For all except the nearest stars, proper motion is only a small fraction of an arc second per year. When this option is turned on, a star's proper motion in right ascension and declination is displayed adjacent to its coordinates in the Object Info window.

Light Time: adjusts the positions of objects in the solar system for the finite velocity of light. We see Saturn in the sky not where it is right now, but instead where it was about 90 minutes ago, because light from Saturn requires about 90 minutes to travel to Earth.

For most objects, the effect of light time amounts to only a few arc seconds. Where light time makes a noticeable difference is in the positions of the outer planets' moons, and especially in planetary rotation.

Dynamic Time: also called Terrestrial Dynamic Time (TDT), this is the standard for precise time keeping in astronomy. It differs from Universal Time (UTC or GMT) because the Earth's rotation is slowing irregularly, due to the gravitational influence of the Moon. We periodically add or subtract "leap seconds" to/from our civil time scale, to keep it in sync with where the Earth is actually pointing. The accumulated difference between UTC and TDT is called Delta T, and its current value is about 67 seconds. Delta T affects the local time when an astronomical event is observed on Earth.

If you turn on the Dynamic Time option, SkySafari adds Delta T to the civil time displayed on your iPhone before computing the positions of solar system objects. If your leave Dynamic Time off, SkySafari will assume that there is no difference between UTC and TDT. This is technically incorrect, but it may be useful to compare SkySafari's results against another reference (such as the Astronomical Almanac) which tabulates an ephemeris of planetary positions against Dynamic Time instead of Universal Time.

Refraction: a distortion in an object's apparent altitude caused by the Earth's atmosphere, which bends light as it passes through. Refraction can amount to over 1/2 degree near the horizon, but decreases rapidly as an object's altitude increases. Refraction only affects an object's apparent altitude, not its azimuth, right ascension, or declination.


The Formats settings let you control how SkySafari displays dates,
times, and celestial coordinates throughout the program.

Formats

The settings in this section let you control how SkySafari displays dates, times, and celestial coordinates throughout the program.

Time

These settings let you choose the format which SkySafari uses to display the time of day.

Date

These settings let you choose the format which SkySafari uses to display the calendar date.

Right Ascension, Declination

These settings let you choose the format which SkySafari uses to display right ascension and declination. These coordinates describe an object's position in the equatorial coordinate system.

Azimuth, Altitude

These settings let you choose the format which SkySafari uses to display azimuth and altitude, which describe an object's position in the local horizon coordinate system.


The Appearance settings let you control the overall "look and feel" of the app,
including sounds, screen brightness, and auto-rotation. Click to enlarge.

Appearance

The settings in this view let you control the overall theme or "look and feel" for the app, and sets its use of color in your sky charts. You can also use a screen dimmer to help preserve your night vision.

App Theme & Behavior

Classic: When selected, the app uses the look-and-feel of standard iPhone controls, which are mostly dark text on light backgrounds. The Classic theme is best for using the app during the day time.

Onyx: When selected, the app uses light text on black or dark grey backgrounds, reversing the standard iPhone look-and-feel.

Night Vision: When selected, the app uses red text on black backgrounds. The Night Vision theme is best used in the dark, out under the stars.

Sound Effects: Controls the use of sound in the app. When turned on, SkySafari plays sounds in response to events such as selecting a new object, connecting to a telescope, and so on. When turned off, SkySafari does not play sounds.

Chart Momentum: Provides smoother panning. When turned on, the chart "glides to a halt" when you remove your finger after swiping. When turned off, the chart stops moving instantly when you remove your finger. Please Note: this feature is only available in the SkySafari Plus and Pro.

Chart Animations: Provides animated panning to objects that you select and center in the sky chart. If turned off, the chart jumps instantly to objects when you center them. Please Note: this feature is only available in the SkySafari Plus and Pro.

Prevent Auto-Lock: When turned ON, this prevents the device from sleeping while SkySafari is active. This allows a continuous connection to a telescope. Please Note: this feature is only available in the SkySafari Plus and Pro.

Toolbar Icon Order: Lets you rearrange the items on the main sky chart toolbar. Tap this item to show the list of toolbar items. Tap and drag the "grip" on the right side of an item in the list to rearrange it. Tap Done when finished. Please Note: this feature is only available in the SkySafari Plus and Pro.

Chart Color & Screen Brightness

Color Chart: Displays stars, planets, and other objects in the sky chart using full color.

Monochrome Chart: Displays stars, planets, and other objects in the sky chart using grayscale, with light objects on a dark background.

Inverse Monochrome Chart: Displays stars, planets, and other objects in the sky chart using grayscale, with dark objects on a light background. This makes the sky chart appear as a photographic negative, and may make it easier to see for those with poor vision.

Screen Brightness: Sets the brightness level of the screen. Turning this down, especially when using the Night Vision theme, may help preserve your visual dark adaptation, as well as save battery life.

When using the Night Vision theme, the sky chart is always drawn with red objects on a dark background (or dark objects on a red background, if you're using Inverse Monochrome sky charts). Again, this is to preserve your night vision - red light affects your dark adaptation much less than white light.

Auto Rotation

Allow Auto Rotation: When turned on, the main sky chart and other views automatically rotate as you turn your device from portrait to landscape mode. When turned off, all views stay in portrait mode, regardless of how you are holding your iPhone, iPad, or Pod Touch.

This setting overrides the hardware rotation lock on the iPad. In other words, if the auto rotation setting is turned off, all of SkySafari's views will remain in portrait mode even if the iPad's hardware rotation lock is disabled. You may want to have other iPad apps auto-rotate, but keep SkySafari in portrait orientation.

Toolbar in Landscape: When turned on, the main toolbar and status bar appear when your iPhone, iPod Touch, or iPad is held in Landscape mode, as well as in Portrait mode. If this setting is turned off, the toolbar will disappear in Landscape mode, giving you a "full screen" sky chart view.


The Horizon & Sky settings control the display of the local horizon,
and the sky background. Click to enlarge.

Horizon & Sky

The settings in this view let you control the display of the local horizon, and the sky background. In SkySafari Plus and Pro, note that the horizon is not visible if you are displaying the sky chart using equatorial coordinates! Use horizon coordinates to show the horizon.

Horizon Display

Show Horizon & Sky: Turns the local horizon and sky background display off or on. When turned off, most of the other settings in this section are disabled.

Show Cardinal Points: Sets whether the cardinal points are displayed along the horizon line. Cardinal points label the north, east, south, and west directions on the horizon.

Show Natural Sky: When turned on, the sky color changes with the cycle of day and night. When turned off, the sky background color is always black.

Horizon Panoramas

This section lists the horizon panoramas that are available in SkySafari. The currently-selected panorama is shown with a check mark. The panorama is only displayed if you've selected Panoramic Image display option above. Choosing any item from the list of horizon panoramas will automatically select this option!


The Solar System settings control the display of planets, moons, and other "minor bodies"
in the solar system (asteroids, comets, artificial Earth-orbiting satellites),
and let you update their orbits. Click to enlarge.

Solar System

The settings in this view control the display of planets, moons, and other "minor bodies" in the solar system (asteroids and comets), as well as artificial Earth-orbiting satellites.

Planet & Moon Display

Show Planets: Sets whether planets and moons are displayed in the sky chart. When turned off, most of the other settings in this section are disabled.

Minor Body Display

Show Asteroids: Sets whether asteroids are displayed in the sky chart.

Show Comets: Sets whether comets are displayed in the sky chart.

Show Satellites: Sets whether satellites are displayed in the sky chart.

with Names: Sets whether the sky chart displays names next to asteroids, comets, and satellites.

Magnitude Limit

This item lets you control the limiting magnitude for solar system objects: in other words, the faintest planets, moons, asteroids, comets, and spacecraft that the sky chart will display. You can use this item to filter out the many hundreds of faint asteroids and comets that are not observable in backyard telescopes - or you may want to show them all!

Please Note: this item is only available in SkySafari Plus and Pro.

Update Minor Body Orbit Data

Tap this button to download new asteroid, comet, and satellite orbit data. If your iPhone or iPod is connected to the internet, SkySafari will download the following files:

These downloads should take 10 - 30 seconds if you are connected to the internet by Wi-Fi, and a 1 - 3 minutes if you are connected by a cellular data network. If successful, SkySafari will report the number of asteroid, comet, and satellite orbits that it has updated. If that number is zero, it probably means SkySafari can't connect to the on-line data sources for this information (because the server is down, or because you are not connected to the internet, etc).

Updating your orbit data every month or so is a good idea. It will ensure that SkySafari's position predictions are accurate. This is especially true for satellites, whose orbits change rapidly due to atmospheric drag, and due to perturbations from the Earth's non-spherical gravity field.

Updating also ensures that as new objects are launched - or discovered! - SkySafari will be able to show them to you.

Please Note: this feature is only available in SkySafari Plus and Pro.


The Stars settings control the display of stars, including the number of stars that will be shown,
the size and color of the star symbols, and the labelling of stars. Click to enlarge.

Stars

The settings in this view let you control the display of stars, including the number of stars that will be shown, the size and color of the star symbols, and the labelling of stars with their names or catalog numbers.

Star Display

Show Stars: Sets whether stars are displayed in the sky chart. When turned off, most of the other settings in this view are disabled.

Magnitude Limit: Sets the star magnitude limit. This determines the faintest stars that are visible in the sky chart. The brighter a star, the lower its magnitude. The faintest stars visible to the naked eye are about magnitude 6.5. Very bright stars can have negative magnitudes; the brightest star in the sky, Sirius, is magnitude -1.44.

The magnitude limit will change automatically as you zoom the sky chart in and out. When zoomed in, fainter stars are displayed.

Star Name Display

Show Names: Sets whether star names are displayed next to some stars in the sky chart.

Proper Names: Sets whether proper names are displayed for stars when possible. When turned off, stars' names are displayed using their catalog numbers (e.g. "α CMa") instead of their proper names (e.g. "Sirius").

Greek Symbols: Sets whether Greek symbols are displayed for stars which have Bayer letters. When turned off, Greek letters are spelled out in English, e.g. "Alpha CMa" instead of "α CMa".

Name Density: Sets the percentage of stars whose names are displayed on the sky chart. At 0%, no stars have names shown; at 100%, all stars have names shown. At 20%, only the brightest 20% of stars have names shown. When the star name density is at 10% or below, only stars with Bayer letters, Flamsteed numbers, or proper names will be labelled.

Double Stars: displays double stars with their component identifiers (A, B, C, D, etc.) as well as their visual separations in arcseconds ("). For binary stars with known orbits, this option also displays the orbital path of the secondary component relative to the primary. Turn this option on, then zoom in on Sirius or Alpha Centauri, and take a look!

Please Note: this feature is only available in SkySafari Plus and Pro.

Star Symbol Options

Symbol Size: Sets the size of the star symbols. Use small, subtle star symbols to give the screen the appearance of the night sky.

Color Intensity: Sets the displayed intensity of the color difference between stars of different spectral types.


The Deep Sky settings control the display of star clusters, nebulae,
and galaxies; and the labelling of such objects. Click to enlarge.

Deep Sky Objects

The settings in this view let you control the display of star clusters, nebulae, and galaxies - including the selection of deep sky objects that are shown, and the labelling of objects with their names or catalog numbers.

Deep Sky Object Display

Show Objects: Draws symbols for star clusters, nebulae, and galaxies in the sky chart. When turned off, most of the other settings in this view are disabled.

Show Images: Displays images of deep sky objects in the sky chart. When turned on, Digitized Sky Survey images of several hundred best-known deep sky objects are drawn at their true size and orientation in the sky chart. Deep sky images can be displayed independently of deep sky object symbols (above), and vice-versa.

Best-Known Only: sets whether only the best-known deep sky objects are shown in the sky chart. These objects include the Messier objects, the Caldwell objects, and any other deep sky objects with a proper or common name.

Please Note: this feature is only available in the SkySafari Plus and Pro.

Show in Wide Fields: allows deep sky objects to be displayed when the field of view is wider than 45 degrees. This option is turned off by default, since deep sky objects can only be seen through binoculars or telescopes, which have very small fields of view. However, turning this option on may let you see the distribution of (for example) galaxies across wide areas of the sky.

Please Note: this feature is only available in the SkySafari Plus and Pro.

Magnitude Limit: Sets the deep sky object magnitude limit. This determines the faintest deep sky objects that are visible in the sky chart. The brighter an object, the lower its magnitude. The magnitude limit will change automatically as you zoom the sky chart in and out. When zoomed in, fainter objects are displayed.

Intensity: Sets the brightness used to display deep sky object symbols and names. Move the slider to vary the brightness from 0% (black) to 100% (white).

Deep Sky Object Name Display

Show Names: Sets whether deep sky objects' names are displayed next to the objects in the sky chart.

Proper Names: Sets whether proper names are displayed for deep sky objects, when possible. When turned off, deep sky objects names are always shown using catalog numbers (e.g. "M 13") instead of proper names (e.g. "Hercules Cluster").

Name Density: Sets the percentage of deep sky objects whose names are displayed on the sky chart. At 0%, no objects have names shown; at 100%, all objects have names shown. At 80%, the brightest 80% of deep sky objects have names shown.

Deep Sky Object Type Selection

Please Note: this section is only available in SkySafari Plus and Pro.

Globular Clusters: Sets whether globular clusters are displayed in the sky chart. These are dense concentrations of stars, typically containing tens of thousands to millions of stars. These massive clusters are among the oldest objects in our galaxy. Examples are M 13 in Hercules and M 22 in Sagittarius.

Bright Nebulae: Sets whether bright nebulae are displayed in the sky chart. These are glowing clouds of gas usually found in the disk of the Milky Way. These nebulae glow either from the reflection of light from nearby stars or from the emission of light produced by nearby stars heating the nebulae. Examples are M 42 (the Great Orion Nebula) in Orion and M 20 (the Trifid Nebula) in Sagittarius.

Dark Nebulae: Sets whether dark nebulae are displayed in the sky chart. These are opaque clouds of cold dust which obscure the light from the stars behind them. They are mostly located along the Milky Way. Examples are B 33 (the Horsehead Nebula) in Orion, and the Coal Sack in Crux.

Planetary Nebulae: Sets whether planetary nebulae are displayed in the sky chart. These are expanding shells of gas expelled from a star late in its life. A round, planet-like appearance led to the name "planetary nebulae" in the eighteenth century, though there is no actual connection with planets. Examples are M 57 (the Ring Nebula) in Lyra and M 27 (the Dumbbell Nebula) in Vulpecula.

Galaxies: Sets whether galaxies are displayed in the sky chart. Galaxies are immense star systems outside of our own Milky Way galaxy; many are larger than our own. The total number of galaxies is in the billions, and they extend to the edge of the known universe. Most galaxies are classified as spiral galaxies, elliptical galaxies, or irregular galaxies, based on their appearance. Examples are M 31 (spiral) in Andromeda, M 87 (elliptical) in Virgo, and the Small Magellanic Cloud (irregular).


The Milky Way settings control how the Milky Way is displayed in the main sky chart.
Click to enlarge.

Milky Way

The Milky Way is the visible concentration of stars, star clusters, bright gas clouds, and dark dust lanes that lie along the plane of our galaxy in the sky. The settings in this view control how the Milky Way is displayed in the main sky chart.

Milky Way Display

Show Milky Way: Turns the Milky Way off or on. When turned off, the Milky Way is not drawn, and most of the other settings in this section are disabled.

Milky Way Intensity

Intensity: Sets the brightness level of the Milky Way when shown as a filled area or realistic image.

Fade in Small Fields: When turned on, the Milky Way's intensity will fade to zero as the field of view decreases from 10 to 1 degrees wide. It is often not useful to show the Milky Way in very small fields of view.

  

The Milky Way can be displayed both as a realistic image (left) and a filled gray area (right).


The Constellations settings control the display of constellations and asterisms. Click to enlarge.

Constellations

The settings in this view let you control the display of constellations - the mythical figures associated with the stars that have been formalized in modern times to define precisely-bounded areas of the sky. These settings can also display asterisms, which are star patterns that are commonly known, but not formally recognized as constellations.

Constellation Display

Show Constellations: Sets whether constellations are displayed in the sky chart. When turned off, most of the settings in this section are disabled.

Intensity: Displays a slider which lets you control the brightness of the constellation lines and labels. Use this to adjust the visibility of the constellations, versus the stars which make them up.

Tap to Select: Sets whether constellations can be selected by tapping the area inside the constellation's boundaries on the sky chart with your finger. When turned off, constellations cannot be selected by tapping - only planets, stars, and deep sky objects.

  

The constellation Orion, displayed using modern outlines (left) and as a mythical figure (right). When displayed
as outlines, selecting a constellation (by tapping it) highights its official boundary area, as defined by the IAU.

Constellation Names

Show Names: Sets whether the sky chart displays the names of the constellations.

Use Abbreviations: Sets whether the sky chart displays constellations names using their official IAU abbreviations (e.g. "CMa") or their fully-spelled-out Latin names (e.g. "Canis Major").

Asterism Display

Show Asterisms: When turned on, asterism outlines are displayed in the sky chart. Asterisms are commonly-known star patterns that are not formally recognized as constellations, or that span multiple constellations. Examples include the Big Dipper, in the constellation Ursa Major; and the Summer Triangle, which contains the brightest stars in the constellations Lyra, Cygnus, and Aquila.

Show Names: When turned on, asterism names are displayed in the sky chart. You can display asterism names independently of asterism outlines.


The Grids & Reference settings let you show or hide grids which display the major
celestial coordinate systems, as well as the reference lines and points that those
systems are based on. Click to enlarge.

Grids & Reference

The settings in this view let you show or hide grids which display the major celestial coordinate systems, as well as the reference lines and points that those systems are based on.

Please Note: these settings are only found in SkySafari Plus and Pro.

Celestial Coordinate Grid

Show Grid: Sets whether a celestial coordinate grid is displayed on the sky chart. When turned off, the following two items are disabled:

Reference Lines

Celestial Equator: Sets whether the celestial equator is displayed on the sky chart. The celestial equator is the plane of the Earth's equator projected onto the celestial sphere.

Galactic Equator: Sets whether the galactic equator is displayed on the sky chart. The galactic equator is the plane of the Milky Way galaxy projected onto the celestial sphere.

Ecliptic Path: Sets whether the Ecliptic path is displayed on the sky chart. The Ecliptic is the plane of the Earth's orbit projected onto the sky. It is also the annual path of the Sun around the celestial sphere.

Meridian Line: Sets whether the meridian is displayed on the sky chart. The meridian is the projection of your longitude on Earth onto the celestial sphere. It extends from the northern horizon through the zenith to the south cardinal point on the horizon. An object is said to transit when it crosses the meridian.

Reference Points

Celestial Poles: Sets whether the celestial poles are displayed on the sky chart. The celestial poles are where the Earth's polar axis (i.e. the line perpendicular to the plane of the Earth's equator) intersects the celestial sphere. The north and south celestial poles are currently in the constellations Ursa Minor and Octans, but they move slowly over the centuries due to precession.

Galactic Poles: Sets whether the galactic poles are displayed on the sky chart. The north and south galactic poles are where a line perpendicular to the plane of the Milky Way galaxy intersects the celestial sphere. They are currently located in the constellations Coma Berenices and Sculptor, respectively.

Ecliptic Poles: Sets whether the ecliptic poles are displayed on the sky chart. The ecliptic poles are where a line perpendicular to plane of the Ecliptic intersects the celestial sphere. The north and south ecliptic poles are in the constellations of Draco and Dorado, respectively.

Zenith & Nadir: Sets whether the zenith and nadir are displayed on the sky chart. This marks and labels the points directly overhead and underneath your feet.


The Scope Control view lets you connect to, disconnect from,
slew, or align your telescope to any object in the database.

Scope Control View

The Scope Control view is used to connect to your telescope and control it remotely. By default, SkySafari's telescope control uses a the Demo interface. This is a dummy virtual telescope that lets you to use the controls without having a real scope connected. To connect to a real telescope, choose the telescope type and communication parameters in the Scope Setup settings view.

The Scope Control view displays the name of the scope's current target object, the scope's right ascension and declination, a motion rate slider. To the right are directional arrow buttons for moving the scope while it is connected.

Connect: This button establishes a connection with your telescope. If a SkyWire serial accessory is connected to your iPhone, iPad, or iPad Touch, then SkySafari will use SkyWire for telescope communication. Otherwise, SkySafari will use Wi-Fi for wireless telescope communication.

Once you've connected, this button's title will change to "Disconnect"; tapping it will end your telescope control session.

Before tapping the Connect button, make sure you've selected the correct telescope type and communication options in the Settings. Make sure the scope is powered on, and any necessary alignment procedures are completed. Consult your telescope manual for details on the scope's alignment procedure.

After connecting, the sky chart is centered where SkySafari thinks the scope is pointing. If you are using your iPhone's compass or altimeter to center the sky chart, these items will be turned off. The sky chart cannot be centered on the telescope's position, and centered on the coordinates reported by the compass/altimeter, at the same time.

GoTo/Stop: This button issues a "GoTo" command to your telescope, which will physically slew it to the coordinates of the currently-selected object in the sky chart. To select an object in the sky chart, tap on it, or use the Search view.

While a GoTo is in progress, this button's title changes to "Stop", and pressing it will issue a command to stop the currently-in-progress GoTo. You can use this as an "emergency stop" if the telescope is in danger of hitting something, or if you have accidentally slewed to the wrong object.

Note that not all telescopes support GoTo commands, and that you cannot GoTo an object which is below the horizon.

Align: This synchronizes the scope to coordinates of the selected object. The bullseye indicated in the sky chart shows where the telescope thinks it is pointing. If that appears incorrect, the scope and the software must be aligned. To do so:

You can re-align the scope and the software anytime there is a discrepancy between the two.

Note: for Celestron NexStar and Orion/SkyWatcher SynScan telescope controllers, tapping the Align button stores the offset between the telescope's reported position and the selected object's position. It subtracts that offset from the telescope's reported position whenever the telescope is within 10 degrees of the object you Aligned on. In other words, SkySafari performs a "local sync" around the alignment target. If you move the telescope to a very different part of the sky, you may want to Align on a target in that part of the sky. Also note that the telescope's RA/Dec reported by SkySafari will differ from the RA/Dec reported by its hand controller (since SkySafari is applying the alignment offset to the telescope's reported position.)

Note: for encoder-based "Push-To" systems, like the Tangent Instruments BBox, Celestron Astro-Master, JMI NGC-MAX, and Orion Intelliscope, SkySafari now lets you perform a 2-star alignment. This eliminates the need to level your telescope mount base. Simply set up your telescope, point it at the first alignment star, select that star in SkySafari, and tap "align". Repeat the process with a second alignment star, but when given the option, align on that star as the "Second Star". Your encoders should now be aligned to the sky. You can continue to align on additional second stars; but SkySafari only uses the two you most recently aligned on. Make sure your two alignment stars are at least 10 degrees apart; 90 degrees apart is ideal. SkySafari will warn you if your alignment stars are too close together, or if their positions don't match - for example, if you've accidentally selected the wrong alignment star in SkySafari, or you're not really pointing the telescope at that star in the sky.

SkySafari remembers the telescope's alignment until you quit the app, so you should not have to realign if you disconnect (or are accidentally disconnected) from the encoder control box. However, if you accidentally kick the telescope mount, or otherwise destroy your alignment, you can realign without having to quit SkySafari. To start over, point the telescope at a star, select the same star in SkySafari, and tap Align. When given the option, align on the star as the "First Star". That will reset SkySafari's alignment process and start it over with the star you just selected.

Lock/Unlock: Tapping this button keeps the sky chart centered on the telescope's position. Moving the telescope will cause the sky chart to move as well, following the telescope's motion.

If you are using your iPhone's compass or altimeter to center the sky chart, these items will be turned off when you tap the Lock button. The sky chart cannot be centered on the telescope's position, and centered on the coordinates reported by the compass/altimeter, at the same time.


The Scope Communication settings specify what kind of telescope
you have, and how SkySafari should communicate
with your telescope. Click to enlarge.

Scope Setup

Use these settings to specify what kind of telescope hardware you have, and how SkySafari should communicate with your telescope.

In order to communicate with your telescope, you will need either:

If you don't have such an adapter, you can also use Carina's Voyager software, running on a Mac or PC with Wi-Fi and a serial port, as a Wi-Fi-to-serial server. See Southern Stars's web site at www.southernstars.com for more details.

Equipment Selection

Scope Type: Use this setting to select the type of telescope to control. SkySafari can control any of the telescopes in the list. Many "Go-To" telescopes can emulate the Meade LX-200 command protocol; you may wish to try that option if your telescope is not listed separately here. Your telescope may need to be set to "LX-200 mode" in order for this to work; check your telescope manual for more details.

SkySafari supports many encoder systems that can read out the telescope position but not actually move the telescope. The Meade Magellan I and II, Losmandy DSC, and Sky Commander are examples of such encoder systems.

Mount Type selection, with options for encoders.
Click to enlarge.

Mount Type: Use this setting to select your telescope's type of mounting:

If your telescope mount has encoders which provide a digital readout of the scope's position, additional text fields will appear here. These let you specify the encoder resolution.

RA/Azm: The number of steps per revolution for the encoder attached to the telescope's Right Ascension axis (or Azimuth axis, if you have an alt-azimuth mount).

Dec/Alt: The number of steps per revolution for the encoder attached to the telescope's Declination axis (or Altitude axis, if you have an alt-azimuth mount).

Get Automatically: If turned on, SkySafari will attempt to read these values from your encoders when it connects to the telescope controller. If turned off, you can enter the encoder steps per revolution manually; then SkySafari will send the values you entered to the encoders when connecting to the telescope. You can do this if (for example) your mount is using gears or pulleys to increase the effective encoder resolution.

Depending how your encoders are installed, their position readouts may increase when they are turned clockwise, or increase when they are turned counterclockwise. If the encoder position readouts increase when they are turned counterclockwise, enter a negative value for the number of steps per revolution. You may need to determine the correct + or - sign by trial-and-error. If you push your telescope left (or up), but the telescope field-of-view indicator on the sky char moves right (or down), the sign is probably wrong.

Communication Settings

The first two settings below (IP address and TCP port) are only used with Wi-Fi telescope communication. If SkyWire is connected to your iPhone, iPad, or iPad Touch, SkySafari will use SkyWire (rather than Wi-Fi) to communicate with your telescope.

IP Address: The IP address of the Wi-Fi adapter or server that is physically connected to the telescope. Your iPhone or iPod must be on the same Wi-Fi network as the adapter or server, and must have an IP address on the same subnet. Check your iPhone's Wi-Fi network settings to make sure this is correct.

Port Number: The TCP port number to be used for communication with the adapter. Make sure this is the same TCP port that the telescope adapter or server is listening on.

Set Time and Location: If turned on, SkySafari will send the time and location from your iPhone to the telescope when establishing a connection. This will overwrite your telescope's previously-set time and location. For older Meade LX-200 telescopes, this may also cause a delay of up to 15 seconds when connecting, so you may wish to turn this setting off.

Readout Rate: The readout rate is the frequency with which SkySafari requests the telescope's position from the mount so it can update the position on-screen. If you set this rate to "4 per second", then SkySafari will request the telescope's position four times every second.

If the telescope frequently stops communicating, the rate of position requests may be too frequent for the telescope to respond properly. Setting a lower readout rate of 1 or 2 readouts per second may solve the communication problem. The optimal readout rate varies with the type of mount used and may require some trial and error to determine. A lower readout rate means that the telescope position displayed on the sky chart will be updated less frequently, and using SkySafari to control the telescope may feel sluggish.

SkyFi Settings Web Page: If you have a SkyFi wireless adapter, this item displays its settings/configuration web page. You must be connected to SkyFi's wireless network in order to see this web page, and the SkyFi's IP address must match the IP address entered at the top of the view.


The Scope Display settings customize the display of the telescope's
field of view in the sky chart. Click to enlarge.

Scope Display

Use the on-screen display settings to customize the display of the telescope's field of view in the sky chart.

Finder & Eyepiece Fields of View

Here, enter the field of view of your narrow field eyepiece, the field of view of your wide field eyepiece, and the field of view of your finder scope. The finder field typically ranges from 2° to about 8°, and the field of view of a telescope eyepiece varies from 2° to a few minutes of arc (about 0.05°). Enter values that describe the finder and eyepieces that you actually use with your telescope.

Any of the above field of views may be selectively shown or hidden by touching the relevant on/off switch.

Crosshairs: Lets you turn crosshairs on or off, which precisely show the field of view center, and indicate the directions of movement of the telescope mount axes.

Telrad Circles: Shows the field-of-view indicators of a Telrad as red circles in the sky chart. These circles are 0.5°, 2°, and 4° across, always centered on the telescope's field of view.

Camera Field Width x Height

This is a rectangle that represents the frame of a film or a CCD camera. If you wish to display the camera field on the sky chart where the telescope is pointing, enter the width and height of its field of view in degrees. Setting the on/off switch to "On" will display this rectangular frame as part of the telescope cursor.

Field of View Display Options

Show Even if Not Connected to Telescope: Lets you display the field-of-view indicators even if SkySafari is not actually communicating with your telescope controller. In this case, the field of view indicators will always be displayed at the center of the sky chart. You may use this feature, for example, to "preview" how a star cluster may appear in a particular eyepiece or finderscope.

Field Rotation Angle: Lets you set the scope field-of-view rotation angle. When zero, "up" in the scope's field of view is north in the sky (for equatorial mounts) or "up" in the sky (for alt-azimuth mounts).

Scope Display Coordinates

This setting determines the coordinate system used to show the telescope's position in the Scope Control view.


Settings Files let you save all of your sky chart options so you can
restore them at a later date. Click to enlarge.

Settings Files

Settings Files let you save all of your sky chart options so you can restore them at a later date. You can email settings files to yourself, or send them to your friends, so that you (or they) can easily reproduce a sky chart which you have created.

To do all of these things, select the Save and Restore Settings item from the main Settings view.

Default Settings: SkySafari creates a default settings file the first time you run the app. This settings file is called "Default Settings", and it contains a "snapshot" of the app the first time it was launched. You can restore SkySafari to its initial state at any time by choosing this settings file.

Saving New Settings Files

To create your own settings files, tap the "Save New Settings File" button. SkySafari will make another "snapshot" of all the app's current settings, and save them as a settings file called "Current Settings." If the date and time are set to something other than current time, the simulated date is used as the file name: for example, "July 11, 2010 Settings" for a settings file that reproduces the total solar eclipse of July 11th, 2010. You can edit the settings file name to something else if you want a more descriptive title.

Description: SkySafari generates a default description for your settings file, to give you an idea of what's inside it. You can edit this description as well. When you are satisfied with the name and description, tap the "Done" button in the upper right side of the status bar to return to the list of settings files that you have already saved - your new settings file is added to the list!

Restoring and Deleting Settings Files

To restore a saved settings file, tap its name in the list of settings files. SkySafari will display the file's description, to let you make sure this is the file you want. If so, tap the "OK" button - and all of the app's settings will be replaced with those from the settings file. You can tap the "Cancel" button if you don't want to do this!

You can delete saved settings files, or re-order the list, by tapping the "Edit" button above the list. This lets you delete items, or move them around, using standard iPhone list controls. When you are done making changes, tap the "End Edit" button.

Editing and Emailing Settings Files

You can view and edit a previously-saved settings file's name and description by tapping the small blue arrow to the right of the file's name. You can overwrite the settings inside the file with a copy of the app's current settings, by tapping the "Update with Current Settings" button. You might want to do this if, for example, you wanted to tweak the settings inside that file, without having to save them to an entirely new file.

You can email a saved settings file to yourself, or to anyone else, by tapping the "Email This Settings File" button. When the email is received, the Mail app on the recipient's iPhone, iPad, or iPod Touch will launch their copy of SkySafari, import the settings file into their list of saved settings, and let them restore the settings you sent them - all in a single step!


Observing Lists

Observing lists keep track of objects you wish to observe, and record a log of your observations. Items in the list can be edited to show the time and date you observed the object, and let you enter notes about your observations of the object. You can share observing lists with friends by email, or send them to yourself for safekeeping.

You create and access observing lists at the bottom of the Search view, in the Custom Observing Lists section.

Creating Observing Lists

By default, SkySafari comes with a single, empty observing list called "My Favorites". To create additional observing lists, tap the Create New Observing List button at the bottom of the Search view. Give your new list a title; you can then add objects to the list.

Adding Objects to an Observing List

You can add objects to an observing list from the Object Info view. Tap the Add Object To Observing List button, located at the bottom of this view, to add the object to your list. On the iPhone and iPod touch you may need to scroll down in order to see this button.

If you have more than one observing list, SkySafari lets you choose which list to add the object to. If you have only a single list, this choice is skipped.

Using an Observing List

Tap an observing list in the Search view to see the objects it contains. Tapping an object in the list provides a choice of:

Sharing Observing Lists

Below the objects in an observing list is an Email Observing List button. Tap this button to create an email message with the observing list as an attachment. Enter the recipient's email address in the "To:" field, and edit the message body as desired. Tap Send to send the observing list to the recipient.

When the recipient receives the email on their mobile device, they can import the attached observing list into their copy of SkySafari. To do this, the recipient should touch and hold the observing list attachment until a view appears with an Open in SkySafari button. Tapping this button imports the observing list into the recipient's copy of SkySafari.

You can email your observing lists with or without observations. This lets you send a "clean" copy of an observing list to someone else. You can also email your observing list as a plain-text attachment, or as a CSV (comma-separated value) text file attachment. This lets you import your observations and notes into other programs.