Feb 5 2012, 01:34 AM
We've seen them...almost every sol.Click to view attachment
Has there been a sunspot (group) large enough to get imaged?
The Sun from MER is about 20pix across on the images
The Sun is 875K miles wide (44K miles per pixel)
The Great Sunspot of 1947 would be about 1.2pix (tall) X 2.5 pix (long) from MER
Or is the filter/resolution not right for sunspot detection?
Here is simulated image from Mars of the Great Sunspot of 1947 (your mileage may vary...)Click to view attachment
Feb 6 2012, 05:25 PM
I am fairly confident that since Spirit landed in early Jan 2004, there have been no spots that have been resolvable with Pancam.
I have wondered about what you asked as well, though had never had the gumption to dig into the smallest resolvable spot. Shows how really curious I was I guess. Anyway, based off total sunspot area (http://solarscience.msfc.nasa.gov/greenwch/daily_area.txt), admittedly not the best measure but the best I can find, the wonderful spots of late October 2003 would have been out best chances, if only a few months later. Since landing, no spots have come close, with the aggregate area of 21Jul04 (MerA Sol 195, MerB Sol 174) coming in at ~40% of 08Apr47's record value.