Fellow blogger Ian has a nice explanation of the how we can see Mercury's Sodium Tail using the STEREO A and B space craft . It's all to do with the angles and timing. Read on here....
Astroblog: Wait! Mercury Has a Tail (and an astreoid occultation)#links
Saturday, April 17, 2010
Wednesday, April 7, 2010
This comet is now passing rapidly through STEREO HI1A FOV. This is a small movie of this faint comet traveling upper right to lower left. Approx Mag is 14 +/- 1 as the imager sees more to the Red end of the spectrum.