Ahmmm, ahmmm.... I was about to post my December 31st OOTW, featuring... Well, you guessed it! NGC 2207 and IC2163! I had just decided to have a quick look for additional observations in the web, when I came across the ... January 13th 2013 OOTW! Oh well, can't believe |I missed it while checking the previous years. well, since I did the effort, here is my write up for the record.... Dragan and Jimi, give me another couple of days for another OOTW!
=====

Object of the Week, December 31 2017: NGC 2207 and IC 2163
Winter evenings can be cold or frigid cold, but when the skies are clear, the starry vistas can be spectacular. The winter Milky Way arches above, straddling Orion the Hunter and his dogs, Canis Major and Minor. These areas are famous for the never ending array of nebulae and star clusters, but hidden amongst the myriad stars and the clouds of hydrogen and dust, are some fine galaxies, such as this week’s objects: the NGC 2207 and IC 2163 colliding pair.

Both galaxies, which reside in the southwest corner of the Great Dog, were discovered by John Herschel in 1835, and they are estimated to be around 85 million light years away. They are of a great astrophysical interest, as they are in the early stages of their collision. Both galaxies still have their original characteristics, but they do show some signs of the impeding situation. NGC 2207 is a SAB(rs)bc peculiar galaxy with a weak ring around the central bar. IC 2163 is a SB(rs)c peculiar galaxy, smaller in physical extend than 2207, that also has a weak inner ring, and a long elongated arm, possibly stretched due to tidal interactions with the larger galaxy. Both members of the pair show high rates of star formation, this being another result of the merging process. NGC 2207 has been quite an active supernovae producer, with four supernovae being recorded between 1975 and 2013.

My personal interest with this interacting galaxy pair started quite recently, thanks to a Sky and Telescope article by Richard Jakiel (February 2016, “Hunting Beneath the Dog”). On page 55 of that issue, a beautiful photo by the NASA/ ESA/ Hubble Heritage Team definitely attracted my attention. Although the article was written two years ago, I did not get around to observing the colliding galaxies until the Thanksgiving evening of 2017! Although the night was far from spectacular, using my 18” dob I could readily detect the pair as two distinct but touching fuzzies even at low power, with one fuzzy patch bigger and brighter than the other one. Increasing the magnification revealed NGC 2207 as an oval haze with a distinctly brighter starlike core, while IC 2163 was a softer, round, uniform patch. At the time of my observation the pair was still below their maximum altitude, and the unsteady seeing hindered my attempts to pull out more detail, though I could suspect more structure, especially in NGC2207. I did not even attempt a drawing, expecting to draw the pair in a better evening. Unfortunately, I was not able to observe again after that night, so I still need to go after this beautiful pair on a good night!

Checking old notes, I discovered that I had observed NGC 2207 before, with my 12” dob back in 2009, but I had not penned any further notes, nor did I mention any observations of IC2163. This is surprising as both galaxies are certainly within range of such an aperture. Actually, they should certainly be within range of a four-inch refractor given a good night and dark enough skies – something which I plan to attempt on my next night out!

Until then, whenever you are out gain this winter and the moon is gone, turn your scope to southwest Canis Major, fish out NGC 2207 and IC 2163, and as always….

Give them a go and let us know!