Object of the Week April 28, 2019- Arp 105 – NGC 3561B and 3561A

[FaintFuzzies]

Object of the Week - Arp 105 – NGC 3561B and 3561A
RA: 11 11 13.3 Dec: +28 41 46
Size: 0.7 x 0.7’ Mag: 14.7

Decided to go for one of my old favorites. This complex has a lot of fun stuff to see, depending on your scope.
For 16” or smaller telescopes, you can probably see both components of NGC 3561A and B (labeled as A and B).
If you have a 20-30”, you can start picking off some galaxies in the field.
Now, if you have access to a 40” or larger scope, give the knot, bridge and plume a shot!

However, this is one of the AINTNO #22 objects from Barbara Wilson’s list. See https://www.astronomy-mall.com/Adven...ace/aintno.htm . One note: We are not sure if the “knot” noted by Barbara is the “plume” to the north or the “knot” to the south.

Jimi and I had a lot of fun observing this object and some really dim stuff. Below are some notes of this object

48” (488 and 813x) - Ambartsumian's knot (labeled as “knot”) was detected as a “stellaring” within a very small glow just off the southern edge of NGC 3561B. The “plume” north of NGC 3561A was detected fairly easily about 3’ north. It appeared as an irregular knotted glow with a very faint, but obvious “bridge” connecting it to the north edge of NGC 3561A. MAC 1111+2843A, a knot just off the NE edge of NGC 3561A was a very faint 2:1 elongated glow pointed away from the center. MCG+5-27-12 was a considerably bright 3:2 elongated glow located 1.5’ SE of NGC 3561B. MAC 1111+2840 was a faint 2:1 elongated patch located 45” SE of MCG+5-27-12. MCG+5-27-15 (located 2.8’ NE of NGC 3561A) was a bright round glow with defined edges. MAC 1111+2844 was an extremely faint round glow and lies just east of the bridge. Another extremely faint glow (unlabeled galaxy) was detected on the other side of the bridge.

I could not believe that the bridge and plume was “blazing” in Jimi’s scope!

Arp105a.jpg

So Give it a go and let us know!

[Jimi Lowrey]

I remember that night well like it happen last week. That was some NIGHT!! And cool observation to bad you don’t get nights with conditions like that all the time.

[Uwe Glahn]

Challenging group Alvin. I tried this object once with my 27-inch under good transparency and seeing with 586x.

no plume and bridge detected, Ambartsumian's knot unsure visible as a stellar popping just S of NGC 3561B, no steadily visible; all three brighter MCG's E detected + an unlabeled stellar galaxy S of MCG +5-27-15

I clearly need another try with larger aperture and better conditions.