The Sun through the dust - Sol 1224

Both MERs take daily measurements estimating the amount of dust in the atmosphere. The less dust the better, because it means more sunlight reaches the MERs' Solar Panels, which power the vehicles. In the last week, Opportunity has broken its dust record, with the Opacity level rising from 1.0 to 3.3.
Solar array energy on Opportunity dropped from 765 watt-hours to 402 watt-hours over the same period of time.

"While this only represents enough dust to coat the Planet to about the thickness of a human hair, it is enough to decrease the brightness of the noon sun by 96% compared to a completely clear atmosphere" said Steve Squyres, Principal Investigator, Cornell University, Ithaca, N.Y.
"Of course, the solar arrays also receive light that is scattered from the dust, so the decrease in power is not nearly that great".