1998-1999 Apparition

Linking Amateur and Professional Mars Observing Communities.

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The International MarsWatch Electronic Newsletter

Volume 3; Issue 3
February 13, 1998
Circulation: 1495

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Dear Marswatch participant,

Here is the latest colorful installment of the MarsWatch news, complements of A.L.P.O. Mars recorders Dan Joyce and Dan Troiani.

--Jim Bell
Cornell University

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MarsWatch News: February 1998

Compiled by Dan Joyce ( and Dan Troiani (,
Association of Lunar and Planetary Observers

Global Surveyor Update

Despite the initial difficulty in achieving desired orbit owing to a weakened solar panel, the Global Surveyor Mission has revealed its prowess. Spacecraft power constraints may force its camera to temporarily shut down soon, but the imagery so far has been a major revelation. Valles Marineris has been found to be stratified to an extent that suggests Mars' geological distant past was more active than had been previously thought by several orders of magnitude. There is even a suggestion of the coming and passing of a sea across the terrain fairly high in the strata. Layering of the kind seen generally in the images could have formed from sedimentary deposits or episodes of volcanism. In neither case was Mars expected to be so active, especially for the amount of time that seems to have elapsed in their formation and how recently the last deposit seems to have occurred. The resemblance to the Grand Canyon in Arizona is remarkable.

Modern computer legerdemain comes into play because distortions introduced by the camera lens and the awkward aspect of the spacecraft motion can be "fitted" to exactly describe what would be seen from a specific point in the orbit using an elaborate averaging technique. One image in particular is of Nanedi Vallis, a sinuous canyon in Xanthe that appears to have resulted from a continuous water flow rather than an abrupt single event, at least that seems to be inferred from apparent downcutting features. There is also evidence of slumping, so both processes may have acted in tandem to produce this valley. This image has resolution to a mere 39 feet, and was the fourth taken during the spacecraft's 87th orbit. The other image highlight is a close-up of Valles Marineris, taken as the third image during the 80th orbit (on the evening of January 1st). It is here that the sedimentary processes are especially prominent. The detail is comparable to that of the Nanedi Vallis image.

In summary, yet another revolution in our thinking of the Red Planet must transpire. Evidently the findings in ALH84001 were just a precursor and probably no accident. We can safely look forward to images over the coming months that will tantalize even more - of such resolution as to not fail to reveal transcending new visions to challenge our already shattered preconceptions of what Mars is all about. The need to explore further will be enhanced, not diminished, by the findings of Global Surveyor, an intrepid if inexpensive explorer of a planet whose lore spans the imaginations of generations.

The 1996-97........ 98 Mars Apparition

As if to mimic Ted Stryk, Jeff Beish joined Don Parker at the latter's observing station and did a Mars sketch on January 21st (!) with Mars all of 4.3 arcseconds and in deep twilight just a few degrees above the southwest horizon. But true to form, South Florida laminar flow held and Syrtis Major and the SPC showed up despite.

Why did we return from the Winter Star Party?!?!?

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Jim Bell will continue to maintain the email distribution list as well as the various Cornell and JPL Marswatch-related WWW archives. If you are receiving duplicate copies of the International MarsWatch Electronic Newsletter, or you want your name added to or removed from the distribution list, please send him an email at

Jim Bell
Cornell University
Department of Astronomy
Center for Radiophysics and Space Research
424 Space Sciences Building
Ithaca, NY 14853-6801
Phone: 607-255-5911; fax: 607-255-9002

Read the Next MarsWatch Newsletter (Volume 3; Issue 4; April 27, 1998)

Read the Previous MarsWatch Newsletter (Volume 3; Issue 2; December 22, 1997)

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This page is maintained by David Knighton for the International MarsWatch. The 1998-1999 MarsWatch site it hosted by the Astronomical League as a service to the astronomical community. Comments, corrections, and suggestions can be addressed to This page last updated December 28, 1998.