NGC 3445 is a one-armed spiral galaxy located in Ursa Major. It is also known as Arp 24 in Halton Arp’s Catalog Of Peculiar Galaxies, which has 338 entries in a variety of categories. Dr. Arp compiled his atlas from photographs he took between 1961 and 1966 using the 200” and the 48” Schmidt telescopes located on Mt. Palomar. His Atlas was published in November of 1966.
As an aside, I was very fortunate to meet Dr. Arp (call me Chip) at a meet-and-greet at UCSD in the mid-1960s after attending a lecture presented by Geoff and Margaret Burbidge… and much of that lecture went right over my head! I attended several Burbidge lectures over the years.
In the eyepiece of my 25” f/5 obsession NGC 3445 was easy enough to pick up and was nearly round. It has a fairly even brightness across its breadth but with a brighter core. I did not know beforehand that this spiral only had one arm, but I did notice a dark skinny “dust lane”, and after staring at it for a while it became clear that there was a fat arm on the south side of the galaxy! Emanating from this arm, almost like an extension (but clearly detached), is a very faint streak of nebulosity, and Sky Tools told me that this is an interacting galaxy, MCG 10-16-24, long and thin (15” X 45”). But wait, there’s more! Approximately 2 arcseconds NE of each of these galaxies is a 10th magnitude star, and within this triangle is yet another galaxy, LEDA 2554198, a tiny mag 17 guy that I did not see, but wasn’t looking for! The interference from the star was substantial. Maybe next time…
I can tell you that there are a couple of other “bonus” galaxies in the area. About 10 arcminutes NW of NGC 3445 is NGC 3440, a mag 14 edge-on spiral, 2.6’ X .7’ and about 14 arcminutes to the NE is NGC 3458, a mag 12.9 lenticular galaxy, 1.4’ X .7’. All 3 of these main galaxies fit easily into a FOV of about 20 arcseconds and can be viewed at the same time in a suitable eyepiece. This graphic is showing a 30’circle…
Addendum: I wrote this OOTW before I left for the eclipse. On April 4th Deb & I were visiting Jimi & Connie Lowrey in Fort Davis, Texas, on our way to the eclipse, and we had the opportunity to view NGC 3445 in Barbarella, Jimi’s 48” dob. Although the seeing was soft it was still a splendid view. Nevertheless, my old eyes could not detect LEDA 2554198, but Jimi says it popped for him a couple of times. What a treat for me to use such a wonderful telescope! Thanks, Jimi.
Reply With Quote