Wednesday, August 17, 2011
Comet Elenin in STEREO H1B (August14)
|Elenin (bright fuzzy patch bottom left) enters the unrolled STEREO H1 Behind imagers field of view on August 14. Click to embiggen. Image processed for NASA/STEREO raw images using ImageJ. Bright lines are imaging artifacts.
||Simulation of the view from STEREO B on August 17 using Celestia (slightly inaccurate due to old orbital elements)|
On August 14 Comet Elenin entered the STEREO H1B field of view without the satellite having to be rolled (tip of the hat to Comet Al for alerting me). Over the next few days we should have some excellent views of the comet, which is quite bright, but not spectacular, in the H1B imager. I've made a little AVI animation of it (2 Mb). A far better animation of the comet from 6 August to 12 August (when the spacecraft rolled) is here (warning 24 Mb animation).
We've been waiting for this ever since Elenin came into range of the H2B wide field imager (see here for animation). We also got some nice images from H1B when the STEREO spacecraft was rolled to position from August 6 (see here (scroll down for animations) and here for images). But now we can see the comet without rolling the spacecraft, which will allow for more consistent imaging.
Location of comet C/2010 X1 Elenin at 8:00 pm ACST as seen from Adelaide. Similar views will be seen in Australia elsewhere at the equivalent time.
If you live in the southern hemisphere, you can see the comet yourself. It is quite low to the horizon at astronomical twilight (1.5 hours after sunset), when it is dark enough to see the comet. Using a telescope can be tricky that low.
The comet is roughly magnitude 9, still to dim for standard binoculars, so currently you do need a modest telescope to see it. However it will brighten over the week and be visible in binoculars by August 27.
Map suitable for locating Elenin in binoculars (click to embiggen).
Use the colour chart above to orient yourself and locate Saturn, then use the binocular map, the circle is the approximate field of view of 10x50 binoculars. You can get orbital elements here.
You can see a recent image of Elenin here.
On 2011-Aug-14 21:00 Jupiter was 16.5° from the Sun as seen from STEREO-B.
On 2011-Aug-14 21:00 Mercury was 21.8° from the Sun as seen from STEREO-B.