From: chaloux@mandolin.mitre.org (Dave Chaloux)
Subject: Mars Observations 12/14/92
Reply-To: chaloux@mandolin.mitre.org (Dave Chaloux)
Organization: The MITRE Corporation, McLean, Va
Date: Mon, 14 Dec 1992 17:56:05 GMT

The night here in Southern Maryland started out cloudy but it had cleared by 11:00 p.m. I got up around 2:00 a.m. with the intent of looking at Mars.
The skies were still clear and stars were reasonably steady with the naked eye
so I proceeded to do exactly that.

I used my 20" F5 at full aperture and at 14" with Magnifications of 280x and
360x. Seeing was fair to good but was never what I would call excellent.
Observations were made between 7:00 and 8:30 UT 12/14.

Upon looking, Syrtis Major was immediately obvious w/o a filter. A somewhat triangular feature labeled Protonilus on the Sky & Telescope map was also visible. The North Polar Cap/Hood was very bright. I used both 25 red and
80A blue filters and determined that the Polar Hood is breaking up as the
Polar Cap was clearly seen in the 25 red filter. The Hood is still there as
the extent of the Hood with the 80A filter is greater than the Cap with the
25 red. I also noticed bright areas near the Southern edge of the planet both
to the E and W. If S on the Planet was 12 o'clock, the bright areas were at
11:30 and at 1:30 at the beginning of the observing session. My initial
thought was that this was limb haze as the areas were first noticed with the
80A filter. However, they were still visible with the 25 Red. It turned out
I was simply seeing the bright areas of Hellas and Ausonia Australis. Hellas
in particular was quite a bit brighter than the surroundings.

I now switched over to using the 25 Red filter exclusively to do a more
thorough job of examining the dark features. Syrtis Major was easily the the
most prominent feature on the planet.  It was especially dark on the northern
portion of the Western edge (Martian West which is roughly Celestial East).

The Tyrrhenum Mare was the second most prominent marking and is connected to
Syrtis Major. An almost circular region within the Mare called Syrtis Minor
was significantly darker than the rest of the Mare. Over near the eastern edge
of the planet and next to the Tyrrhenum Mare was the part of the Cimmerium
Mare called Hespera. To my eye this looked detached from Syrtis Minor although
the maps show them as joined.

Protonilus was just South of where the Polar hood was. It was triangular shaped
and matched the chart in Sky & Telescope (11/92) much better than the
elaborate network drawn in Astronomy (11/92). The tip of the triangle pointed
SSW. Careful examination during a few periods of better seeing also revealed
the nearby feature Alcyonius N. but it was very faint.

The Hadriacum Mare that devides Ausonia Australis and Hellas was also seen
and although brighter than Alcyonius N. was hardly what you would call prominent.

Toward the end of the observing session, I was also able to make out Serpentis
Mare which joins near Syrtis Major. Earlier in the session, the planet had not
rotated enough for it to be visible.

Finally I was able to spot a very faint "canal" that joined Syrtis Major and
Protonilus during moments of better seeing. This "canal" is called NiloSyrtis.
It joins Syrtis Major at the Northern tip where Syrtis Major has a distinct
hook that points roughly NE. This hook was also visible only during moments of
the best seeing.

At this point common sense took over and I decided that if I was going to go
to work in the morning, I had better go back to bed rather than waiting for
Jupiter to get higher up. The moon would have served as a pleasant place to
spend some time while I waited but sleep beckoned.


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