2003:  Mars at its Nearest

by Matt Allard and Philip Steffey

 
Mars was observed during eight evenings from late August to late October with the 14-inch telescope, and in six sessions we watched and recorded video images with an inexpensive color "electronic eyepiece" (lenseless camera) and a 13-inch monitor with built-in, two-head VCR.  Normal summer cloudiness and Daylight Savings Time prevented an earlier start, but we were lucky to have clear or partly clear skies during seven sessions-- especially in August when the planet came to 34.6 million miles from Earth.  Mars' celestial altitude averaged about 30 degrees for the early sessions to 45 deg. for the last.

The videography was done at focal lengths of 300, mostly, or 420 inches, by using Barlow lenses, giving martian images nearly 3 or 4 inches across on the monitor in late August to 2 or 2.5 inches in late October.  No neutral or color filters were used.  Imperfect tracking by the telescope's sidereal drive, the lack of a fine-focuser, and occasional mount shaking due to nearby automobile traffic or passing trains, made image centering and focusing adventuresome, but still we had satisfactory to very good views on the monitor except when clouds intervened, and we obtained over three hours of recorded images.  The low-end VCR with VHS tapes produced slightly degraded recordings, but plenty of frames have yielded adequate still pictures. 

The accompanying stills were obtained using the Apple Video Player running on a PowerMac 8500.  Three "frame-freeze" methods were used.  A good ten of about 30 single frames were chosen for image processing, done to the best of our, subprofessional, ability with Adobe Photoshop 2.5.  Due to differing frame quality, uniformly bright or colored final pictures were unachievable, but the colors shown are visually realistic on average.   The pictures are ordered by observation date to highlight the changing, generally shrinking, martian south polar ice cap, at the top of each image. The planet's south pole was tipped toward Earth by 19 to 23 deg. and the "phase" or fraction of sunlit disc decreased from 100 to 90%.  Captions give the angular diameter and longitude of the central meridian ("CM").  Global longitude coverage is good.

On Mars' disc, the first three pictures show the smoking-pipe-shaped Sabaeus Sinus and Meridiani Sinus (the "bowl"), the shorter Mare Serpentis extending up and rightward, the Syrtis Major along the sunset limb, and the duller, roughly rectangular Mare Erythraeum in the morning hemisphere.  The September 6 image shows the Syrtis Major below center with the attached Mare Tyrrhenum extending leftward and Sabaeus S. and M. Serpentis rightward. South of  Syrt. Maj. is the very low desert Hellas.  Sept. 13, left to right:  the maria Sirenum, Cimmerium and Tyrrhenum.  Sept. 26 features the small, dark Solis Lacus (north of the polar cap) in the "Eye of Mars" formed partly by the trailing edge of M. Erythraeum, with M. Sirenum near the sunrise limb.  Several more dark areas and deserts can be identified from maps.  On the last image, most of the dark band is M. Sirenum, and notice the tiny size of the polar cap as well as the pronounced phase defect.     

    


 

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