*******Special Announcementt*********
17 April., 1997
From Coordinator, Daniel M. Troiani

New Mars computer program available at Sky & Telescope WEB Site!

Which Side of Mars Is Visible?

To compare what you see on Mars with a map, you need to know which side of the planet you're looking at -- in other words, the longitude of the disk's central meridian.

The central meridian is the imaginary line down the center of the disk from pole to pole. The table here gives its Martian longitude (in degrees) at 0:00 Universal Time every day through the end of May. Read across the top to the month, then down to the date (which is also in Universal Time).


Bonus! Windows 3.1/3.11/95 users are welcome to download Mars Previewer by Leandro Rios, an amateur astronomer in Argentina. Rios based his freeware program on the same algorithm used to generate the following table; these calculations are explained in Sky & Telescope's September 1990 issue, page 296, and a simpler BASIC version of the program (MARS.BAS) is available on our Software Page (in line 110, change the value of DT to its current value, 62 seconds). After you download mp.zip (3.2 megabytes), unzip it and run setup.exe to install the software. (The setup utility is in Spanish but behaves like any other Windows 95 setup program, so you should be able to run it without difficulty.) When you run Mars Previewer, make sure you enter dates in dd/mm/yyyy format and set your time zone relative to Greenwich Mean Time (positive numbers to the west, negative to the east). Click on the small image above to pull up a full-resolution screen shot (39K jpeg) of Mars Previewer in action for 0 hours Universal Time on 22 March 1997 (five days after the red planet's favorable 1997 opposition). If you have any questions about the program, you can contact Rios by e-mail at leandror@ba.net.

*  Clear Skies!!                                     *
*                                                    *
*  Daniel M. Troiani                                 *
*  Mars Section Coordinator,                         *
*  Association of Lunar and Planetary Observers      *
*  Schaumburg, IL                                    *
*  Astronomer and Assistant Show Production,         *
*  Cernan Earth and Space Center,                    *
*  Triton College                                    *
*  dtroiani@triton.cc.il.us                          *
*                                                    *

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