Sunday, November 24, 2013
Comet C/2012 S1 ISON enters STEREO H1A (20 November, 2013)
|Comet C/2012 S1 ISON imaged in the STEREO satellites H1A instrument on 20 November. 2P/Enke is to the right and ISON is the big bright thing to the bottom left. 13 images stacked in ImageJ and aligned . Click to embiggen||12 Images stacked in ImageJ, then the images differenced to cancel out stars and assembled into an animation. You will need to click on the image to embiggen it, The process crops out ISON, but you can see the movement of Enke's tail.|
Comets ISON has finally entered the field of view of the STEREO H1A instrument. The left-hand image was processed in ImageJ as usual, The right-hand image was processed using a difference macro in ImageJ which subtracts out non moving pixels to bring out more details with the comets. Enke and ISON have active tails (which you can't see for ISOn as it just enters in the last few frames), but you may wish to compare the 20th in H1A with the comets appearance on the 20th in H2A.