A tourist on Mars

by Akkana Peck

Three nights of clear skies (or at least partially clear) and reasonable seeing out of the last four have given me the opportunity to sketch Mars and become more familiar with the features currently pointed toward us, using a friend's Takahashi 5" refractor.

It's fun to see the consistency between the features I can see from night to night; it's also fun to see some of the differences, the features that disappear in poorer seeing or when nearer the limb.

Monday night was perhaps the best seeing when I first took a look, but while I was sketching I was puzzled by the way the contrast seemed to be getting continually worse -- and then looked up and discovered that clouds had rolled in and Mars was barely visible. Tuesday night, though, had no clouds and I was able to spend more time looking for as much detail as I could see. Then I went inside, scanned and flipped the sketch (since I used a refractor with a star diagonal, the image has to be flipped to match a normal chart view) and spent some time with a globe (the small Replogle one) and a couple of atlases (the one in the RASC Observer's Handbook, and the ones in a wonderful Patrick Moore book on Mars which David found at an auction last year). The result is at http://www.shallowsky.com/images/sketch/mars51199L.jpg

Mare Acidalium and Niliacus Lacus (great name!) are an easy catch in most telescopes this week as the big dark smudge coming down from the pole, as is and Mare Erythraeum as the very dark line in the south. The pole is very small -- it looks smaller than I remember it being a month ago, though a month ago I didn't have much opportunity to view the planet in steady air so my views then weren't reliable. More interesting features include Achillis Pons, a small light patch dividing Mare Acidalium and Niliacus Lacus; Cydonia, which was clearly visible as a lighter area adjacent to Niliacus (no, I didn't see the "face" :-); and Margaritifer Sinus, recognizable as a curving "horn" of darkness standing out from the other fingers of darkness stretching north from Mare Erythraeum. When I looked on Tuesday night at 11pm PDT, Sinus Meridiani was probably the dark smudge disappearing off the eastern limb; over the next week or so, Sini Meridiani and Sabaeus will show progressively earlier, and if the weather holds we should get a good look at them and at the light area separating them from Erythreaum/Magaritifer.

West of Acidalium is a light area, Tempe, and then a noticable dark area which is unnamed on any of the maps I checked (though it is plotted on most maps). The online ALPO map, though, has it labelled as Idaeus Fons. South of Niliacus, Xanthe and Chryse span a large light area and I can't tell them apart.

Lacus Solis, the "pupil" in the "eye of Mars", was barely visible on May 8th when it was close to the meridian, but I have not seen a hint of it since then when it's been closer to the limb. It's much more subtle than the rest of the eye. However, the northeastern part of the eye is interesting in its own right -- Valles Marineris is there, a huge canyon 4000 km long, larger than any canyon on earth. It doesn't look like a canyon in the telescope, just a noticable dark smudge.

The Tharsis plateau, with its volcanos, appears just a large blank area to me. I haven't been able to make out any detail or even any lightening in the area, with or without filters, nor have I been able to see a hint of Olympus Mons itself, alas.

Mars FAQ: http://www.shallowsky.com/mars.html
My Mars sketches: http://www.shallowsky.com/marssketch.html