Mars Apparition of 2014 – Part II
This has continued to be my least productive Mars apparition since I joined the Association of Lunar and Planetary Observers ("ALPO") and began to seriously observe Mars in 2001. As mentioned in my previous Mars article in the June issue of Stars & Scopes, I got a really late start observing Mars in late April when it was already past opposition. Due to a combination of our travel schedule and miserable weather, it only got worse after May. I was completely shut out in June and early July and Mars has now shrunk to about 8.5 arcseconds. That's a bit too small to see the kind of fine detail I like to hunt for and sketch.
I did manage to observe and sketch Mars two more times in May after the observations I included in my June article in our newsletter. The two observations discussed here are of a similar view; however, the first observation was made during a period of poor seeing. The second was made in good seeing and shows more detail. I tried imaging both Mars and Saturn during the latter session, but totally messed up. I had previously set the field size for a broad view of the northeastern quadrant of the Moon and forgot to change it when I imaged the planets. The result was lots and lots of black space with teeny-tiny little planetary disks which were too small to show detail and which dissolved into pixels when I tried to enlarge them. My bad!
Here's the first drawing, which was done on a mostly clear night, but one with unstable air and sustained winds of 16mph with stronger gusts. I was unable to focus with my 400x eyepiece; the most I could manage was 311x.
The above drawing shows the foreshortened Acidalia plain discussed in my June article, as well as the Chryse plain in the center of the preceding (P) side of the disk. The Erythraeum region is to the south (up) of Chryse and the area of Solis Lacus is to the right (west) of Erythraeum, but not visible to me on this night. The west, or following (F) side of the disk contains Mars' Tharsis bulge, on which sit some of the biggest volcanoes in the solar system. The biggest is Olympus Mons, which is about 17 miles high with a base approximately 400 miles across- about the size of Arizona. The slope of this extinct volcano is so gradual that the mountain doesn't cast the kind of dark, sharp shadows you see from mountains on the Moon when the solar angle on the Moon is low. This makes actually seeing Mt. Olympus in the eyepiece very difficult, although it can be imaged with a scope like my C11 and today's more advanced digital cameras. I recall thinking I might have caught a passing glimpse of it during the very close Martian apparition of 2003, but was never sure I did. I did manage to record an orographic cloud over Mt. Olympus in a sketch I made during the apparition of 2007-2008.
The second drawing has Acidalia and the Chryse plain closer to the central meridian and I was able to see some of the Solis Lacus area, also popularly known as the "eye of Mars".
The Chryse plain is almost 1,000 miles across and 1.2 to 1.9 miles deep. This dusty depression is the bottom end of many outflow channels that carried water down from the southern highlands in the very ancient past when Mars had a thick enough atmosphere to permit liquid water on the surface. The Solis Lacus area is the location of the Valles Marineris. This valley was not named for the Italian pasta sauce, but rather for the Mariner Mars probes which discovered it. The Mariner Valley extends for some 2,500 to 3,000 miles, is as much as 300 miles across at its widest points and around 4 miles deep. Earth's Grand Canyon is a ditch by comparison. This valley system may have formed as a tectonic crack when the Tharsis bulge rose up to its west. It may have been deepened by water with the ultimate outflow ending in the Chryse depression.
I'm already looking forward to the next Mars apparition in two years. Mars' disk will be larger than what we saw this year…hopefully the weather will be better too.
Jay Albert, 2014-07-17