This page lists the answers to the questions that we most often recieve about SkyChart III via telephone and e-mail. You might try checking this page first if you have a question -- you'll probably find the answer faster here!
How much does SkyChart III cost, and where can I purchase a copy?
Registered users of SkyChart III can order an upgrade from previous versions for $19.95 plus shipping and tax (where applicable). Upgrades can only be ordered directly from Southern Stars Systems; we do not offer them through resellers.
Educational institutions can purchase a 15-user SkyChart III site license for $299, or an unlimited campus-wide site license for $999. For details, please send us an e-mail or call us toll-free at (866) 887-7827.
I have an older computer. Can I run SkyChart III even though my computer does not meet your system requirements?
SkyChart III will actually run on a 100 MHz Pentium or PowerPC computer with 64 MB of RAM, although a 233 MHz Pentium II or PowerPC G3 processor and 128 MB of RAM is really reccomended for better peformance. If you are running on an older computer, you should turn off the Rendered Objects feature, in the Draw menu; this feature is extremely processor- and memory-intensive, so turning it off should speed up the program greatly.
SkyChart III will run on Windows 95 if Internet Explorer 4.0 or higher is also installed, although we do not officially support this configuration. The Macintosh version will only run on Mac OS 8.6 or higher.
I downloaded a SkyChart III update or demo version from your web site, but when I tried to install it I got an error message saying "Corrupt Installation Detected". What's wrong?
The file you tried to install was an incomplete or partial download. Try downloading the file again. We find that the AOL built-in web browser has trouble downloading files larger than 2.0 megabytes; you might want to try switching to a different web browser. If all else fails, send us an e-mail, and we'll try to email you back a copy of the file. Please tell us what file you're trying to download (demo or update), and what version you need (Macintosh or Windows). Please note, however, that many e-mail servers (particularly AOL) do not allow us to mail you any files larger than 2.0 megabytes, so this option may not work either.
I downloaded a SkyChart III update from your web site, and now the program starts up with a blank window or an error message saying that a file could not be found. Or, I downloaded an update but nothing changed. What's wrong?
The updater program that you downloaded from our web site looks for your current SkyChart III program folder, and replaces the SkyChart III executable file inside it with a new one. For some reason, occasionally the updater will fail to find the correct folder, and install the new executable in the wrong place.
To correct this problem, first determine the directory where SkyChart III is currently installed on your computer. On Windows, this is usually Drive C: -> Program Files -> SkyChart III. On the Macintosh, this is usually your Applications folder -> SkyChart III. (If all else fails, you can use your computer's Find or Search command to find your existing SkyChart III folder.) Then run the updater again, and pay careful attention to the directory where the updater asks to install the new file. This should be the same directory where SkyChart III is already installed; if not, you should change to the correct directory before allowing the updater to continue.
How do I find the Big Dipper?
The Big Dipper is not a formally-recognized constellation; rather, it's an asterism (group of stars) inside the constellation Ursa Major. Select Find... from the Edit menu, type "Big Dipper" into the dialog box that appears, and click the Find button. That should center the part of Ursa Major containing the Big Dipper on the screen.
I changed my location, but every time the program starts up, it says I am located in San Francisco. How do I make SkyChart III save my location?
After changing your location (or, for that matter, any other setting you wish to have the program start up with by default), use the Save Default Settings command, in the File menu. This will overwrite the default settings file, and ensure that SkyChart III starts up with your new settings every time.
I can't get SkyChart III to print anything!
Older releases of the SkyChart III CD-ROM (3.2.1 and earlier) shipped with a printing bug that prevents the program from working properly with certain Windows printer drivers. You can download an update which should fix this problem.
If you are still having trouble, try turning off the Rendered Objects feature, in the Draw menu. If that doesn't solve the problem, send us an e-mail describing the problem. Be sure to include what kind of computer, version of the operating system, what type of printer, and version of the printer driver you are using.
I imported a file containing satellites/asteroids/comets, but the objects in the file don't appear on the screen. What's wrong?
The reason is probably that the objects in the file are fainter than the limiting magnitude for solar-system objects. To change this limit, select the Symbols & Grids command, under SkyChart III's Draw menu. The limiting magnitude for solar system objects is under the section for Draw Planets. You can remove the solar-system-object magnitude limit by deleting the value in this field; then all solar system objects will be displayed, regardless of how faint they are.
Why does SkyChart III appear to use 100% of the CPU, even when no animations are running?
It has to do with the way SkyChart III processes Mac OS events and Windows messages: it polls for them, rather than simply handling them when they are dispatched by the operating system. This is more of a cosmetic problem than anything else; rest assured, SkyChart III does actually share the CPU, so your other programs can run happily along side it. We expect to address this issue in a performance update before the end of 2002.
Why is Earth visible out in the heavens even when viewed from a location on Earth, as on the settings file "Triple Conjunction"?
When the program draws the planets, it puts a mark (symbol, sphere, etc.) where the physical center of the planet is. Technically, since you're 6,378 kilometers from the center of the earth when you're standing on its surface, the center of the earth has a definite direction relative to you, and can therefore be plotted against the stars.
When I display the north polar region for dates earlier than about 10,000 B.C., Polaris and the other polar region stars move away from the celestial pole in an arc, and then move almost randomly across the sky. Why?
SkyChart III uses the formal IAU formulae for precession. These formulae are designed to work for times within a few hundred years of the present. Far outside that timespan, they "blow up" to unrealistic values. Rest assured, the earth did not actually wobble in haphazard random directions many thousands of years ago; this is simply the result of using formulas outside the interval they were designed to predict.
We've been experimenting with using different formulae with a longer timespan, but the currently-shipping version still uses the same IAU formulae. One difficulty with using non-IAU formulae is that they are a standard, and calculations performed with other formulae (even if those formulae are more accurate over a longer timespan) will differ from the standard calculations, which can be a source of confusion. This is something we expect to address in future releases.
Can I import a batch of text files at one time, rather than individually?
If you create a text file named "FileList.txt" and enter into it the names of individual import files, you can import a batch of individual text files at once. You can also use it to import text files in subdirectories, and create corresponding subdirectories in the SkyChart database folder.
For instance, suppose you wanted to import a bunch of different satellite files, and you wanted them to all end up in a subdirectory called "Satellites" in the "Database" folder. Inside your FileList.txt file, you'd have something like:
Satellites\GPS.tle Satellites\Glonass.tle Satellites\Weather.tle Satellites\TV-and-Radio.tle
You'd then put all the input .tle files in a directory called "Satellites" and put that directory in the same directory as the FileList.txt file itself. After importing the files into SkyChart, you'd get a subdirectory in SkyChart's "Database" folder called "Satellites", which would contain all of the same files your input "Satellites" folder, except their names would end in ".skd" instead of ".tle" and they'd be in SkyChart's binary format, not TLE format.
Each line of the "FileList.txt" file represents both the path of the individual input text files relative to the "FileList.txt" file, and the path of the desired output SkyChart database file, relative to the root level of the "Database" folder.
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This page was last updated on 31 January 2003.