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.
