Spirit cleaner? |
Spirit cleaner? |
Jun 18 2007, 06:44 AM
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Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
I've been keeping an eye on the sundial images looking for signs of a cleaning event. I've noticed some changes in the latest to be downloaded although they may be due to changes in the lighting.
A : clean patch at top of circle streak at bottom B : increased contrast from dust left behind next to mirror C : clean patch next to wire Also note the missing clumps of dust on the deck A broader view show a contrast between sol 1221 and 1227 http://207.7.139.5/mars/spirit/navcam/2007...I4P0165L0M1.JPG http://207.7.139.5/mars/spirit/navcam/2007...00P1914L0M1.JPG Has anyone heard if there has been a change in the power levels? |
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Jun 28 2007, 05:57 AM
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
Tau values were made by Viking Landers based on pre-programmed solar brightness observations. When the sun wasn't visible at exposure settings used, the values are lower limits. I *think* values of optical tau over 6 were indicated. Scene brightness levels dropped DRAMATICALLY, with darker horizons than higher skys and with more or less no shadows. Many/most of those images were badly underexposed Of course, once new exposures were selected and upllinked, the opacity dropped a lot, and the images were badly whited-out.
Thermal infrared tau values were measured from orbit with the infrared thermal mapper, a multi-channel radiometer and are about 1/10th (as I recall) the optical values. Pre-Viking data are poor. Mariner 9 data was re-analyzed but I don't recall results and the worst of the storm was 2 1/2 OR 3 MONTHS before Mariner arrived. |
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