Sunday, January 8, 2012

Mars time

C8+ She was a beauty!
Back when I still had my first "real" telescope, a Celestron Super C8+ I spent many nights and mornings observing and drawing Mars during it's 2003 apparition.  this was the famously close pass between Mars and Earth when the apparent size of Mars exceeded 25 arcseconds in diameter.  Two things happened as a result of all those observations: First, I decided I needed an even better planetary scope and sold that Super C8+ to fund a refractor. Second, I became a much better observer.

I regret selling that telescope for several reasons, including the sentimental fact that it was the telescope that took me from having a passing interest in astronomy into the realm of being a serious amateur astronomer.    Using the Super C8+ I observed all the Messier objects, several comets, a couple asteroids, all the planets, and a few hundred other delights.  Additionally, now that I have much more experience using telescopes, I believe it had the best optics of any of the SCT design telescopes I have owned (4 as of now).  Sure I purchased an excellent Stellarvue 4 inch refractor with the money from the sale, but in hindsight that refractor should have complimented the C8+ not replaced it.

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Observing and drawing Mars night after night back in 2003 honed my skills as an observer more than any other period of time.  Many of you know that Mars reveals is dusky markings only to the most patient of observers, and perhaps more than most types of observations, practice and repetition makes a large difference.  It is typical to sit at the eyepiece for 20 to 30 minutes to note the subtle shading of Martian surface features.  Many times I will show folks Mars in my telescopes and all they will see is a red globe (or orange, or salmon, etc...depending on the observer).  At right is a page from my log book from that 2003 apparition, including 2 sketches made with the Super C8+.

Currently, Mars is much farther from Earth than it was on that night in September 2003.  Back then, Mars was .399 AU and had an apparent diameter of 24.9 arcseconds.  Today, Mars is nearly the same distance from us as the Sun at .973 AU, and it's apparent size is a paltry 9.6 arcseconds!  (One AU is the average distance between the Sun and the Earth, or approximately 93 million miles).  Nevertheless, observing Mars in a fine planetary instrument like my TEC 140 is sublime.

Click to enlarge
I completed the sketch at left at 14:10 UT (7:10 AM MST) using a magnification of 196X.  I began my observation of Mars about 40 minutes earlier at 6:30 AM local time and watching Mars as the dawn light was breaking was a peaceful and satisfying way to make my first Mars observation of the current apparition.  At magnitude 0.0, Mars is fairly bright and observing in the light of dawn aided in reducing the glare of the planet.  It is hard to capture in a sketch how subtle the markings on the planet are- however the feature that is most obvious is the North Polar cap, at the top of my sketch.  the planet rotates from east to west, or from left to right in the drawing.  You will notice that Mars is not fully illuminated, and is currently 92.3% full.  In the coming weeks, I will continue to make morning observations of Mars and over the next month will observe features on the other side of the planet.  Mars rotates once every 24.6 hours, so if one observes Mars at the same time each day, it will take several days to begin to see other areas of the Martian surface.  In my sketch, the central meridian of Mars is approximately 233 degrees.

Wikipedia maintains an excellent page on Mars, and for more detailed observing information,  I recommend Jeff Biesh's article "The 2011-2012 Aphelic Apparition of Mars."  It is also worth noting that in November, NASA launched the latest mission to Mars, The Mars Science Laboratory, nicknamed Curiosity.  The homepage for the mission has a tremendous amount of information and some cool video of the launch.

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