Posted in place of Akarsh Shima (we switched places for this week only)
This object was originally catalogued as a single IC object as it was probably not resolved when first discovered. After taking a look at this relatively unknown trio a little while ago, I can see why. The three members are so close together that it occupies a space of 35-40”. That is arc seconds, not arc minutes. Just think, Jupiter at opposition is about 50” apparent diameter. It would obscure the entire group! So you need to crank the magnification to see the individual members.
I could not find any professional work on this group, but sure that it is out there. I’m interested in learning a little more about this group. Is it interacting? Optical trio? I’m pretty sure that it is interacting based on the halo surrounding all three galaxies. I’ve kinda out of date on finding research papers in the astrophysical world.
Notes from my most recent observation with a 22” reflector under mag 7+ skies at a site at 7,800 ft above sea level can be found below. I’ve observed this object several times, including once with my old 16” reflector. It was a very faint unresolved group at 610x through the 16”.
22” (230, 383, 591 and 690x) – This IC galaxy is actually a very compact triple galaxy system arranged in a 30-60-right triangle that occupies a very small space of 35-40” across. This trio is resolved at 591 and 690x. Requires some patience sitting at the eyepiece to see all three members.
PGC 11389 – Very faint very small galaxy located at the right angle of the triangle. 0.1’ across.
PGC 11388 – Extremely faint very small round glow. <0.1’ across. Sitting at the 60 degree angle and just 15” due south of NGC 11389.
PGC 11390 – Extremely faint very small round glow. At the 30 degree angle and 35” due east of PGC 11389.
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