Grand Canyon Star Party, sketched while providing views of Mars to the public.
Date: 06/26/03 Lat 36N, Long 112W, elev. 7500 feet | Sketch Time (UT): 10:15, (local time): 2:15 a.m. MT (mountain time) |
Central Meridian: 330° | Filters: none |
Instrument: 14.5-inch f/4.8 Litebox reflector, Nova primary mirror | Distance from earth 0.59 AU, 89m km, 54m miles |
Magnification: 180x (10mm Televue Radian) | Transp. 6/6, Seeing 8/10, Antoniadi (I-V): I - II |
Apparent Size: 15.9" | Magnitude: -1.3 |
I first noticed the South Polar cap (top) was ringed with a dark circle - which turns out to be the so-called melt line, the area of Martian earth uncovered as the polar cap receeds. Below the south polar cap (north and to the left) is Hellas, the great impact crater basin which was the source of a dust storm a few days later, which changed the color of the area.
Dark areas: Mare Serpentis, Iapygia (lighter area right on the terminator between Syrtis Major and Hellas, ut actually rotated on a bit after I sketched) and Mare Tyrrhenum surround Hellas on the north (below) side. Sinus Sabeaus is the long "arm" extending left to right in the sketch.
A part of Chryse, an elongated lighter area is visible on the lower right limb of the sketch.
Mars, in this sketch is reversed N/S. South is shown at the top of the image. The south polar cap is the prominent feature. Terminator is where daylight ends and evening begins. The terminator is on the left and the planet is rotating left to right. In my sketches the planet rotates Martian east (left) to west (right) to match most other images and sketches. Look for features rotating from left to right in the drawings.
Details about Mars: Diameter 15.9 arc seconds (Jupiter is about 30 -50 arc seconds in diameter depending on its distance from earth). Central Meridian 330 - the imaginary line passing through the planetary poles of rotation and bisecting the planetary disk, and is used to determine the longitude during an observing session.
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