Hunting Comet Catalina in Mississippi Mills

Earth Centered Universe Program helps hunt down the Comet!

Pre-dawn Thursday Jan 7 2016 Observing Report

cometCatalinaECUAnnotatedRhoBJanuary 7 2016, I peeked out  (at 1 am EDT) and waited for Jupiter to shove over and allow Arcturus to rise,… the sky cleared around 3 am. With the 6″ f8 Stargazer Steve telescope at 30X  I found globular cluster M3 and visually ‘drew’ a line down to Rho Bootes. Comet Catalina revealed itself roughly at the midpoint. It looked better with a 60X eyepiece. At first I didn’t think it was so large (in the field of view), but comparing it again to M3 reset my observing prejudice. It’s certainly not bright nor could I  see much of a ‘tail’ of gas or dust. The above is the customized finder chart generated using the computer program ECU (Earth Centered Universe). Using some optical aid is essential – binoculars or telescope – don’t expect to see it naked eye. Don’t expect to observe it in light polluted skies. (But you can observe it, and the other star clusters because we preserve our night skies in Mississippi Mills! ) In any event –  the comet was  not to be confused with the star cluster M3 – as Charles_Messier made sure to catalog this object as ‘not a comet’.

Detailed finder charts are probably a good thing for hunting the comet down visually – the overview chart is a bit too small scale.  Best to  use a planetarium program like ECU (by RASC (Royal Astronomical Society of Canada) member Dave Lane.

Overview Finder Chart – courtesy Sky and Telescope

It’s also better if you tilt the star chart to match the rising of the constellation BOOTES

Discovered by the Catalina Sky Survey on Halloween 2013, the comet received the “US10” designation because it was initially thought to be an asteroid in a short period orbit. After more observations to refine its path and additional photographs that revealed telltale comet fuzz, astronomers realized they’d run into a denizen from the Oort Cloud, knocked our way by the close passage of some nameless star long ago – See more at: Sky and Telescope article Comet Catalina sails into Northern Skies

Orbital Elements
C/2013 US10 is an Oort Cloud comet with a steeply inclined orbit of 149°. It’s spent much of its time lately below the plane of the solar system, out of view of Northern Hemisphere skywatchers. After solar conjunction at mid-month, it will transition to northern skies and arc over the inner planets. On January 12, 2016, the comet comes closest to Earth at 66.9 million miles (107.7 million km).
– courtesy NASA / JPL


When observing the comet through the eyepiece …

Comet?  … or Star Cluster?…Catalina C-2013 US10M3-400x266

Catalina C-2013 US10
Catalina C-2013 US10 – Courtesy Bob Olson Ottawa Astronomy Friends.

From images, particularly this beautiful shot by Ottawa Astronomy Friend, Bob Olson,  it’s pretty clear what’s a comet and what’s a globular star cluster (Messier Object 3). But in the eyepiece of a small telescope or binoculars, it might be very hard to tell the difference. This is why we have Charles Messier to thank, because the entire Messier Catalog was created to disambiguate comet from cluster!