Mars 2003 Revisited

The evening of August 16, 2003 was exceptionally clear, dry, even mild for the season. I (Phil Steffey) was at Bethune-Cookman College's observatory with Matt Allard, the Computer Network Manager for the Mathematics and Sciences Department and an astronomy enthusiast of over a decade. We, with occasional help from other local amateur astronomers, had gotten the observatory's 14-inch Celestron Schmidt-Cassegrain telescope in condition for educational use (Moon, Sun, planets, double stars, a few deep-sky objects) after several years of neglect, and this effort was continuing. Friends of Matt from Orlando were expected to join us, and when they arrived the dome had been open for an hour and the 'scope was ready for viewing of our prime target: Mars.

Less than two weeks from its nearest approach to Earth in 60,000 years, the planet was a dazzling, yellowish orange star in the southeastern sky. The telescope, at 150 and 300X, revealed a midsized, bright south polar cap and dark surface detail sufficiently contrasty to belay my worry about dust storm veiling, which had ruined much of the 2001 apparition. One of the visitors shot some pictures at the eyepiece with a hand-held digital camera. The captured images turned out poor, mainly because they were too small, but the exercise planted an idea in my brain.

Almost a year earlier I had purchased a color "electronic eyepiece" i.e. lensless video camera, from Orion Telescopes and Cameras, and had used it with two small telescopes at home to display very nice images of the Moon and Sun on a 13-inch TV monitor. With a built-in VCR, the monitor was convenient for videotaping these images, albeit at less than ideal quality. In December '02-February '03, I and Matt had used the camera on the B-CC telescope to image Saturn and Jupiter with fair results we knew could be improved as we gained experience.

Following the Aug. 16 session (which incidentally included Uranus as a neat, slightly bluish disc at 300X), I thought Mars in the 14-inch might interest the college students and faculty more than other celestial objects we had offered during our once or twice a month observing sessions. Live video images would be more sensible to most visitors than eyepiece views and would add a high-tech touch. Matt agreed and we planned to use the 'scope this way beginning the week of Mars' closest approach. Sadly our preparation was inadequate and we were waylaid.

Matt notified several faculty members that we would open the observatory for Mars observation, and Aug. 27 was clear for a first event. But the notice leaked to the local news media as an invitation to the general public. When Matt and I arrived to prepare the telescope and set up the video equipment, expecting one to two dozen visitors, there was a line of over 100 stretching from the observatory entrance down three floors of the science building and out its south entrance. Some people had come before sunset! And more were arriving. We managed to climb through the crowd to the observatory, opened the dome, and got the telescope working. But placing the TV monitor where a lot of people could see it proved impossible, and in the end we provided eyepiece views, one viewer at a time, luckily assisted by Professor Richard Copeland, till after midnight.

On Aug. 30 Matt and I tried again, but now only a couple visitors appeared. We obtained video images of Mars better than I expected and videotaped over an hour of them. Perhaps faculty members and students who missed seeing the planet live might be interested in tape playback. Five more observing sessions in September and October also drew few visitors but yielded almost four more hours of videotaped images. More details of the whole project are in the article "Mars at its Nearest" at www.cookman.edu/observatory. The still pictures of the planet shown there were made by me with very limited computer processing software and skills, and I emphasize that live streaming images were our first priority.

In late 2004 and the first half of '05 I made new processed still pictures from hundreds of raw video images captured directly from the tapes with the Flash-It utility or Avid Videoshop's "snapshot" feature, or from filmstrips made with the Apple Video Player or Videoshop. Still lacking automatic frame-stacking software, I manually stacked 2 to 8 raws depending on individual frame quality. Processing of stacked raws was done with an old version of Photoshop but improved personal skill in its application. Contrast, brightness, and color (remove excessive red) were the main adjustments, followed by noise reduction and weak sharpening. Nine representative, resulting pictures from six observing dates are shown in the first set below. Mars' south pole is roughly up and the planet's rotation is leftward. See the B-CC observatory website Mars article for descriptions of the main dark surface features in these pictures. The taped, streaming images remain a little better than these stills.

A second set of pictures below compares a processed video image of Mars with central meridian near 0 deg, with drawings made during the close approach periods in September 1956 and August 1971 and a typical film photograph made in '71 a composite of several relatively short exposures (from Sky and Telescope, Nov. 1971, p. 262). Our image shows less detail than the drawings but accurately records the positions and shapes of the the large surface features. And it closely rivals the photograph, made with a telescope having twice the aperture of ours.

Finally, in reviewing our videotapes in late 2003 I spotted several narrow, dark streaks in some images at positions of the once-celebrated "canals". The first round of still frame stacking and processing was so imprecise that, not surprisingly, these fine features were lost. But some raw images and even a few stacked ones recently made do show the streaks. Three examples are reproduced in the third set of pictures below, and more could have been. Most show up in several raws recorded minutes to an hour apart and can survive stacking, so they are not optics or video artifacts. Of course they are not waterways but chance alignments, straight or curved, of very small dark areas in desert terrain, visible in eyepieces or recordable with very short exposures when the transmittance of our atmosphere is ideal. The angle of incidence of sunlight on the "canal" regions, and the transparency of the martian atmosphere, are other visibility factors. Further discussion is beyond the scope of this article.

Matt and I look forward to Mars' opposition in late 2005, when we will be ready with a better video camera than the Orion and better recording equipment.

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