Observation of Shakhbazian 166

Observation of Shakhbazian 166
By Steve Gottlieb

A few days ago, while observing at the Sierra Buttes (7200') I took a look at UGC 10638 (Shakhbazian 166), which is actually a linear chain of 11 galaxies in Ursa Minor. I ran across this faint galaxy group while scanning through Sky Survey images of the Shakhbazian catalogue of compact groups. Shk 166 was the first entry from this catalogue which I've observed with my 17.5" and most of the groups have members in the 17th-18th magnitudes range at best, so these are definitely challenging targets. I'd be interested in hearing if anyone has tried tackling other faint groups in this catalogue.

The observations below were made at 220x and 280x in mag 6.5 skies. Positions are from the Lick Northern Proper Motion Reference Galaxies (NPM1G) and the identifications from the NASA-IPAC Extragalactic Database (NED).

Steve Gottlieb
http://www.ngcic.com/ngcic.htm

Components of Galaxy Group Shakhbazian 166
Name RA Dec Description
MCG +14-08-015 = CGCG 367-019 = NPM1G +81.0089 = Shk 166-2 16 50 58.7 +81 34 29 First in the Shakhbazian 166 group (UGC 10638) with five members observed in a 6.7' chain oriented SW-NE! This object was typical of the members of the group (the 3rd brightest) - extremely faint, round, 15"-20" diameter. Located 1.5' NW of a mag 12 star. This object is actually a triple system although the faint, compact companions to the NE and S were not visible.
MCG +14-08-016 = NPM1G +81.0090 = Shk 166-3 16 51 45.0 +81 35 31 Second of five in the UGC 10638 chain (Shk166) and very similar to M+14-08-015 located 2' SW. Appears as an extremely faint round "knot" perhaps 15" in diameter.
NPM1G +81.0091 = Shk 166-4 16 52 12.9 +81 37 13 Third of five in Shk 166. This extremely compact object appeared as a 10" knot just 40" SW of a mag 13 star and was the fourth brightest in the group.
MCG +14-08-017 = CGCG 367-021 = NPM1G +81.0092 = Shk 166-1 16 52 47.7 +81 37 58 Brightest in the UGC 10638 chain. Like all members, this object appeared as a featureless round spot ~20" diameter (a bit larger than the other members) situated 50" E of a mag 13 star.
MCG +14-08-018 = NPM1G +81.0093 = Shk 166-7 16 53 17.0 +81 38 51 Last and furthest NE in a linear chain of five galaxies with a 7' total length. This galaxy was the faintest in the group appearing as a 15" round spot with averted vision. Located 1.5' NE of M+14-08-017 (brightest in the group).

Name	RA	Dec	Description
MCG +14-08-015 = CGCG 367-019 = NPM1G +81.0089 = Shk 166-2	16 50 58.7	+81 34 29	First in the Shakhbazian 166 group (UGC 10638) with five members observed in a 6.7' chain oriented SW-NE! This object was typical of the members of the group (the 3rd brightest) - extremely faint, round, 15"-20" diameter. Located 1.5' NW of a mag 12 star. This object is actually a triple system although the faint, compact companions to the NE and S were not visible.
MCG +14-08-016 = NPM1G +81.0090 = Shk 166-3	16 51 45.0	+81 35 31	Second of five in the UGC 10638 chain (Shk166) and very similar to M+14-08-015 located 2' SW. Appears as an extremely faint round "knot" perhaps 15" in diameter.
NPM1G +81.0091 = Shk 166-4	16 52 12.9	+81 37 13	Third of five in Shk 166. This extremely compact object appeared as a 10" knot just 40" SW of a mag 13 star and was the fourth brightest in the group.
MCG +14-08-017 = CGCG 367-021 = NPM1G +81.0092 = Shk 166-1	16 52 47.7	+81 37 58	Brightest in the UGC 10638 chain. Like all members, this object appeared as a featureless round spot ~20" diameter (a bit larger than the other members) situated 50" E of a mag 13 star.
MCG +14-08-018 = NPM1G +81.0093 = Shk 166-7	16 53 17.0	+81 38 51	Last and furthest NE in a linear chain of five galaxies with a 7' total length. This galaxy was the faintest in the group appearing as a 15" round spot with averted vision. Located 1.5' NE of M+14-08-017 (brightest in the group).