Mars is rapidly pulling away from the Earth. On the 21st of June, we passed closest to it, just 42,000,000 miles or 0.45 AU away. And while the Red Planet will dominate the southern evening sky through the rest of the summer, the size of its disk has slipped from a maximum of 21 arc seconds, to 17 by the beginning of August, and to a mere 13 by the end of the month.

So if I was going to get an image of Mars, now was the time. Equipped with the club’s STV camera and my newly arrived 10” LX-200, I was ready. The earth-bound hardware performed flawlessly, with accurate tracking in alt-az mode (with only one-star alignment), minimal mirror shift and silky focusing. Blood-thirsty mosquitoes, of course, but they come with territory. A famous astronomer once commented that the atmosphere was the worst part of a telescope, and I’m afraid I may have demonstrated the truth of that statement. But there were moments of good seeing and sharp clarity when surface features of Mars were unmistakable. The rotation of the planet was obvious as the night wore on. Some of my images are here: left, f/10, 6 frame composite, unsharp masked, 6 July 2001 about 23:00 EDT and, right, f/20 + yellow filter, 9 frames 13 July at 22:30. With more hand-on experience, a truly steady atmosphere or another site might produce even better results. After all, this is off-the-shelf hardware at my sea-level backyard “observatory”!

You’ll note another consumer electronics item in the center of the photograph. The “video out” jack of the STV allows taping directly the imaging session to any VHS video recorder. Variations in seeing are easily seen, as are the challenge of focusing and the accuracy of finding and tracking. I’ll bring the tape to the August monthly meeting to show anyone interested. In the meantime, if I can get the video digitizer to work, I’ll post some video clips linked to this page. Note that these are only quick and dirty samples of the video (versus simply imaging) capabilities of the STV. The ability to record the video out has tremendous potential for documenting and time-shifting astronomical events. Many things move and change in the sky: possibilities include occultations of stars by the Moon, transits and eclipses of Jupiter’s moons, space station watching. Tape recording in "real time" makes a great teaching tool for group “observing” even on cloudy nights. For those unfamiliar with the STV, it is an easy way to learn to image and autoguide. There is great potential in video astronomy beyond just beating the seeing.

Barsoom is the locals’ name for Mars in Edgar Rice Burrough’s science fiction classic “The Gods of Mars” published in 1913. What was speculation and fantasy then is now the subject of active exploration and intense scientific interest. With seasons like Earth’s, the possibility of vegetation, and even canals built by intelligent life forms, Mars fired the public’s imagination, then and as now. The real Red Planet has come into view since the Mariner and Viking spacecraft of the '60's and '70’s: craters and volcanoes mark a rocky landscape not unlike our barren deserts. Much better resolution has been achieved with the recent missions: Pathfinder - Sojourner, Mars Global Surveyor and Odyssey, currently halfway to Mars. Even from Earth orbit, the HST provides a knock-your-socks-off view. With an amateurs’ ability to image surface detail with unprecedented ability, anyone can now casually watch the weather on another planet. Amazing stuff: what one hundred years ago was inspired fantasy is today’s backyard pastime.

Since Mars’ takes roughly twice as long to orbit the Sun as the Earth, there will be no close approach next summer. But in late August 2003, Mars will make one of its closest possible approaches at only 34,000,000 miles (0.37 AU), and its disk will stretch 24 arc second across. Even better, opposition will occur in Aquarius, and Mars will be near -15 degrees declination, thus appearing higher, and hopefully steadier, in our sky. Will the STV be outdated technology by then? Will every telescope come with a web-cam accessory and LCD screen? Will inexpensive adaptive optics gizmos take the shimmer from the eyepiece? Doubtless we will be better equipped to welcome Barsoom back to our sky. And I’ll be trying again to image Mars. I could use the practice!

Moondark is written by Doug Miller, published on the web , and printed in the Delmarva Star Gazers'Star Gazer News and the Delaware Astronomical Society's FOCUS. Please address comments and suggestions to dcmiller@dmv.com. This document was last revised on 22 July 2001. All text and images copyright © 2001 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.