Forums / The Science / Visual Observing / Comet 103P Hartley in Auriga this October
Comet 103P Hartley in Auriga this October
Apart from the obvious reason to look at stars in the constellation of Auriga, Comet 103P Hartley will be a few degrees away from Capella on October 20th.
Cometary magnitudes are never a sure bet, but this one is predicted to be around magnitude 5, but diffuse, spanning around half a degree (full Moon size). So the darker your skies, the more likely it is to be visible to the unaided eye. The comet's closest approach to Earth will be on October 21 at 18 million km. It should still be putting on a good show in late October and early November after the Moon has stopped interfering.
In the Southern Hemisphere the comet is better situated for viewing in early November, although I do plan to get out at around 5am on or near October 20th to see it about 13 degrees above my horizon. 
Here's a few relevant links:
http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=103P
http://www.astronomy.com/asy/default.aspx?c=a&id=10173
http://en.wikipedia.org/wiki/103P/Hartley
Enjoy.
Regards,
David
I was looking from Toronto with 15x70 binos when it was going through Cassiopea, but had no luck. Iam guessing it is rather diffuse.
I have made one attempt so far (at 5am on Oct 21) from my suburban front yard, the only place I had a hope of seeing it from my house, but its low altitude and a streetlight in just the wrong place made it too difficult to spot. Sara Beck saw it from Ireland recently. :)
My kids and Iobserved it from our backyard when it was in Cas with a 4" refractor, but a couple nights later we were not able to see it again with 12x80's. It is now in a difficult spot from my backyard, so we haven't tried again.
Dear all, On Oct 19 night we got some hole (!) in the clouds after several days of poor weather, at that time 103P was expected right into our epsilon field ( very near, east of HR1644) Sky & Tel guys were considering it naked eyes, visible about mag 4.5, ok, I should see it from my terrace ! (I am on top of a building) AUR stars were well visible but no hint of any fuzzy ball... I got my 10x50 bino, all my usual ref stars were well visible but nothing near HR1644... For sure no risk for epsilon DSLR photometry shots ! Itookmy series of shotsas usual and next pushed the ISO to 1600, reduced the time to 4 sec to avoid too much star trail, and took 30 shots centered on HR1644 (notracking, not enough time to setup an equatorial... ) Back on computer I saw something fuzzy just at the expected position ! But on next morning I had to leave for a couple of meeting days in Paris, no time to process the30 shots. Back to Dijon (France) this weekend I did it with my software under Dyalog APL. It waswell there but I really wonder it wasmag 4.5 ! My best estimate fromthe stack is about mag 6 ~ 6.5 But I agree photometry of such thing is very difficult, it needs to eliminate number of superposed mag 9 ~ 11 stars and the noiseis high.The extent of the tail seems about 0.7 deg. The attached epsilon AUR field view has been processed and a gamma appliedfor a best viewing on monitor, bright stars are clipped at 1000 ADU. Yours truly, Roger
| Attachment | Size |
|---|---|
| Hartley2_AA19.png | 396.07 KB |
| Hartley2_Graph.png | 64.4 KB |
Looking at finder charts, it looks like it might be close enough to eps Aur to slightly interfere with photometry for a short time. CU HB This one is from http://www.oculum.de/newsletter/astro/100/20/0/1-01_hartley2_map_g.jpg