Object name: NGC2805

Designation(s): NGC2805, NGC2814, NGC2820, IC2458,

HOLM 124 is a group of 4 galaxies in eastern Ursa Major, southeast of M81 and M82. At one time it was considered part of the M81 group but then redshift and other distance determinations showed it much more distant at say 84 to 100 million light-years. The main galaxy in the group is NGC 2805. It shows a lot of distortion from its interaction with the others three millions of years ago. Its arms are quite angular except in the core region. Most edges are linear rather than curved and it has some rather odd arms such as the spur to the west coming from its northern end. Other arms show lots of star-forming regions that NED shows as other galaxies except for one labeled Part of Galaxy (PoG). I've shown them in the annotated image but since their redshift matches that of the galaxy they are unlikely separate galaxies. The galaxy is quite blue, likely due to all the star formation going on in it.

The other three members of the HOLM 124 group are to the upper left; NGC 2814, NGC 2820 and the really disrupted NGC 2820A/IC 2458. NGC 2814 is made up of several bright blobs. The only reddish one is well above center near a foreground star. The central blob is quite blue but does appear to have a short edge-on linear dust trail through it but it doesn't continue into the other blobs. I sure would like to know what it looks like more face on. NED classifies it simply as Sb: agreeing it is an edge on spiral.

NGC 2820 is also an edge on spiral with an odd extension from the west end. NED classifies it as SB(s)c pec sp. It too has a star cloud that NED shows as a separate galaxy though it looks to my eye to be a bright star cloud in the galaxy. Being blue I don't see it as the core of some galaxy being eaten by the much larger 2820. NGC 2820A seems to be the most torn up of the four. Being small that isn't all that surprising. NED uses the brightest of the star clouds at its north end for its position rather than an average of all its parts. The north end appears to be made of a close bunch of star-forming clouds while the southern region looks almost like a separate galaxy with a blue core and star disk around it though the "core" is oblong and likely another star-forming region as it is blue. NED classifies it as I0 pec:.

NGC 2805 was discovered by William Herschel on April 2, 1791. It is in the second Herschel 400 observing program. NGC 2814 and 2820 were also discovered by William Herschel but on the following night, April 3, 1791. Or was it the same night, just after midnight? I find this a bit ambiguous. These two aren't in either Herschel 400 program. NGC 2820/IC 2458 was discovered by Guillaume Bigourdan over 100 years later on March 14, 1899.

The annotated image shows the more distant galaxies that NED shows a redshift for. This is a retake of a much earlier image, 2007, that was taken on an even better night but back then my collimation was off so stars are a bit screwy. Color data was severely damaged due to a light leak I didn't know was there. This created a gradient in the luminance channel and a red gradient in the red frames. Back then I didn't have either the knowledge or tools to deal with it. Due to these issues, I did a complete retake on March 22, 2017 UT. The first clear night with good seeing in months.

14" LX200R @ f/10, L=4x10' RGB=1x10', STL-11000XM, Paramount ME

Related Designation(s):

2MASS J09202045+6406105, 2MASS J09211139+6415132, 2MASS J09211144+6415121, 2MASS J09213011+6414189, 2MASS J09214548+6415284, 2MASX J09202040+6406099, 2MASX J09211152+6415117, 2MASX J09213008+6414195, 2MASX J09214556+6415288, 2MFGC 07261, 2MFGC 07265, 2MFGC 07269, ASK 446442.0, ASK 446446.0, CGCG 0916.3+6419, CGCG 0917.1+6428, CGCG 0917.5+6427, CGCG 0917.8+6429, CGCG 312-002, CGCG 312-003, CGCG 312-004, CGCG 312-005, CGPG 0917.5+6427, CXOU J092020.6+640607, EON J140.442+64.258, FGC 0877, GALEXASC J092130.07+641419.0 , HDCE 0520 NED001, HDCE 0520 NED002, HDCE 0520 NED003, HIJASS J0920+64, HOLM 124A, HOLM 124B, HOLM 124C, HOLM 124D, IC 2458, IC2458, IRAS 09162+6418, IRAS 09170+6428, IRAS 09177+6428, IRAS F09162+6418, IRAS F09177+6428, KTG 23A, KTG 23B, KTG 23C, LDCE 0635 NED001, LDCE 0635 NED002, LDCE 0635 NED003, LGG 173:[G93] 001, LGG 173:[G93] 002, LGG 173:[G93] 003, LGG 173:[G93] 005, MCG +11-12-003, MCG +11-12-004, MCG +11-12-005, MCG +11-12-006, MRK 0108, NGC 2805, NGC 2805:[SMM2013] X-01, NGC 2814, NGC 2820, NGC 2820A, NGC2805, NGC2814, NGC2820, NSA 076834, NSA 135848, NSA 135851, NSA 157206, NVSS J092146+641526, PGC 026410, PGC 026469, PGC 026485, PGC 026498, RFGC 1537, SDSS J092020.38+640610.6, SDSS J092020.38+640610.7, SDSS J092130.07+641419.3, SSTSL2 J092111.35+641514.1, UGC 04936, UGC 04952, UGC 04961, UGCA 159, UZC J092020.4+640610, UZC J092111.5+641506, UZC J092130.2+641417, UZC J092145.3+641528, UZC-CG 096 NED01, UZC-CG 096 NED02, UZC-CG 096 NED03, UZC-CG 096 NED04, VII Zw 276, WBL 218-001, WBL 218-002, WBL 218-003, [H84a] 0917+645, [M98j] 064 NED01, [M98j] 064 NED02, [M98j] 064 NED03, [SMM2013] 113,