HCG 50 observed with 30"

by Randy Muller

Three of us (Brian Zehring, Alvin Huey and I) were able to observe at least one component of HCG 50 last night at Blue Canyon (5284'), February 21, 2003. This is by far the most challenging of the Hickson Compact Groups (of galaxies) to observe, and is probably not observable by ordinary mortals in scopes smaller than my 18".

We used Brian Zehring's mammoth 30" f/4.3 Starmaster, which also happened to be getting its official first light.

Using a 13mm Nagler (252x), we were able unambiguously to find the proper field, which is located only 21 arc minutes nearly due east from M97, the famous Owl Nebula.

The field itself is not only easy to recognize, getting there is easy as well: 12' mostly east and slightly south of M97 lies a fairly bright trapezoidal figure about 5' across consisting of two mag 10 stars (TYC 3825-19-1 and TYC 3825-27-1) and two mag 12 stars (TYC 3825-24-1 and TYC 3825-22-1).

Continue east 5' from TYC 3825-22-1 to arrive at the mag 13 star GSC-3825-0023. This forms one corner of a triangle with GSC-3825-0104, almost 3' further east. The third corner is a mag 17 star (USNO-A2.0 1425-07637517) located at 11h 17m 5s +54d 54m 51s.

I gave a little hoot when I saw this object at the third corner, because I thought at first it was one of the components of Hickson 50. Alvin had a DSS photo of the field, showing a tiny (and I do mean tiny) oval of 5 galaxies, with a more stellar-looking object outside the oval. This object was in exactly the same position as what I was seeing.

This star could be held easily and steadily with averted vision.

It was evident to Alvin and me that we needed more power, so Brian popped in a 6mm Nagler (546x), and we began to examine the field very closely for extended periods of time.

Alvin studied the field while I went back to my chart (sans the dim galaxy-like star) to verify once again that we had the right field.

When Alvin was done, I mounted the ladder and studied the field.

I intermittently (perhaps 10-25% of the time) observed an extremely faint fuzzy patch a small distance (about 20") at about the 11 o'clock position from the mag 17 USNO star (12 o'clock being straight up). At our local time and latitude this was NE of the USNO star. The fuzzy patch seemed to be multiple objects, but how many was impossible to say.

Alvin observed the same patch in the same place and seemed to think it consisted of 3 galaxies.

HCG 50A is offset 15-20" roughly NE of the mag 17 USNO star.

For an Aladin visualization of this field, see