December DAS Focus

COMPUTERS IN ASTRONOMY by Don Shedrick

Last month I listed some web sites for downloading SkyGlobe version 3.6 for DOS at:

http://www.telescope.org/rti/guide/brad/lo0.html

and the version 4.0 for Windows. The Windows version web site is now blocking access to the general public, so I have searched for another web site for this rare version of the SkyGlobe program. After an extensive search, I found it at, believe it or not, an Australian astrology software site:

http://www.matrix.com.au/download.html

This is SkyGlobe version 4.0, and includes the DOS version 4.0 as well . The Windows version is really version 1.0 - the first Windows version, and it still has problems running on some PCs. I just found an even rarer Windows version and apparently the latest - version 2.02. This version includes a setup utility, and has installed without a hitch on every computer I have tried from an ancient Win 95 machine to a new Windows XP machine. While the setup is installing, a couple of files come up with a message saying they cannot be found. Just click OK and keep going - the program will run fine without them. Find this latest Windows version at:

http://www.geocities.com/CapeCanaveral/Launchpad/8602/astro/programas.html

This web site is in Spanish, but the link will be obvious. The web site appears to be for an Astronomy Club from Sao Paulo, Brazil. Maybe someone can do some translating for me.

By the way, both the DOS versions (3.6 and 4.0) run just fine on the new Win XP machine.

Both Jupiter in Gemini and Saturn in Taurus are in ideal locations for observing this month. I have listed below some programs that are useful aids in observing these planets. These programs have been featured in this column in the past. While many are on the DAS Astro BBS, I will review them again here with their web site addresses, so you can download them by simply clicking on the hot links in this article.

 JupSat95 is a handy program that provides info on where Jupiters satellites and Great Red Spot are going to be for your observing session. This program is available on the DAS ASTRO BBS or from the web site of the author of the software at:

http://indigo.ie/~gnugent/JupSat95/

The program calculates the positions and displays side-on views as they would be seen through one of three optical configurations (Binoculars, Astronomical Telescope, Star Diagonal) and plan views of Jupiter and its satellites, along with the Longitude of Jupiter's Central Meridian for both equatorial and non-equatorial zones. It also displays (and can print) monthly satellite tracks, Great Red Spot transit times and allows animation.

TRACKER, an MS-DOS program, can be found on the DAS ASTRO BBS and at:

http://www.physics.sfasu.edu/astro/dansoftware.html

It uses the time and date from your computer's clock to determine and display the approximate locations of a few features on the southern or northern hemisphere of Jupiter as seen from Earth. In addition to the Great Red Spot, other features displayed include the major white spots, the smaller white ovals, and small red and dark spots and streaks. Impact sites of the fragments of comet Shoemaker-Levy 9 are displayed as dark spots if you set the time to late 1994. The actual positions of these features are constantly drifting with the Jovian clouds, so to keep this program accurate, the data base needs to be kept current with the latest longitude information for their location based on current observations. This is fairly easy to do with this program, but finding the data for features other than the GRS is more difficult. The GRS longitude is published in Sky and Telescope (currently 76 deg). Data for other features is usually available with varying promptness and detail on the Association of Lunar and Planetary Observers (ALPO) web site at :

http://www.lpl.arizona.edu/alpo/

JOVIAN MOON EVENTS is an MS-DOS program available on the DAS ASTRO BBS and at the web site:

http://www.physics.sfasu.edu/astro/dansoftware.html

This program computes the time for Transits, Shadows, Eclipses, and Occultations of Jupiter's Moons for one month accurate to within one minute. The table generated is similar to that offered in the Astronomical Almanac, and the output is printed to a file. A similar table is displayed on the Project Pluto web site:

http://www.projectpluto.com/jevent.htm#sep

and a table for the Great Red Spot transit times is at another of their web sites:

http://www.projectpluto.com/jeve_grs.htm#sep

A unique Strip Map of the surface cloud features of Jupiter is on the web site of an ALPO-Japan member Yuichi Iga:

http://www.kk-system.co.jp/Alpo/Jupiter00/Stripmap.htm

Additional Jupiter Observing Events and many Jupiter related links can be found at the web site of the Stephen F. Austin State University Department of Physics and Astronomy:

http://www.physics.sfasu.edu/astro/jupiter.html

Saturns famous rings are now in a very favorable position for viewing in their 29 year cycle of tilting up and down. In addition to the rings, there is the nightly dance of the moons of Saturn, four of which are readily observable in small telescopes.

SATSAT - Satellites of Saturn v2.0, is an MS-DOS program on the DAS ASTRO BBS and available on the web at:

http://www.physics.sfasu.edu/astro/dansoftware.html

This program will use the time and date from your computer's clock to determine and display the locations of the moons of Saturn. The rings of Saturn are also displayed, showing their angle of tilt and the shadow they cast on the planet. Other orbital data on Saturn and its moons are given as well. There is an animation feature so you can set the moons in motion and observe the changing tilt of the rings.

Satview is an MS-DOS program available on the DAS ASTRO BBS and at:

http://www.bookcase.com/library/software/msdos.education.astronomy.html

This program projects a mathematical model of a sunlit Saturn from any angle. You can select parameters resulting in views that would be unfamiliar and impossible to be viewed from Earth, such as from a spaceship flying over the poles of the planet. You enter three values to create the image - the altitude of the sun above the ring plane, the altitude of the viewpoint above the ring plane, and the difference in azimuth between Sun and the Observer as measured from Saturn. There are an infinite number of possibilities to try out.

Additional Saturn observing events can be found at the web site of the Stephen F. Austin State University Department of Physics and Astronomy:

http://www.physics.sfasu.edu/astro/saturn.html