Object name: NGC3158

Designation(s): NGC3158, NGC3150, NGC3151, NGC3152, NGC3159, NGC3160, NGC3161, NGC3163,

The NGC 3158 group is composed of 8 NGC galaxies and many others a bit over 300 million light-years distant by redshift. NGC 3158 is a huge Elliptical galaxy whose gravity anchors the group. I get a size of 275,000 light-years for its outer reaches. It was discovered by William Herschel on March 17, 1787 and is in the second Herschel 400 object list.

Half the NGC members were found by Guillaume Bigourdan on February 1, 1886. He found NGC 3150, 52, 59 and 61, all in the southern part of the group. R.J. Mitchel working for the Earl of Rosse found two, NGC 3152 and 3160 with the last, NGC 3163 also found by William Herschel the same night as 3158. It, however, isn\'t in either Herschel 400 listing.

NGC 3159 is listed as an E2 spiral and as peculiar. That may be due to the very faint plume to the south. Ignoring the plume it is 67,000 light years across. The plume fades away so I\'m hard-pressed to determine an edge but my best guesstimate puts it at least 200 arc seconds long making it over 300,000 light-years in size though of much lower mass than NGC 3158.

NGC 3160 is a strange spiral likely involved in a collision to create its odd structure. It is about 83,000 light-years across. NGC 3151 at 60,000 light-years is an SA0 Galaxy/ NGC 3152 is also rather odd being a ringed barred spiral with no arms, just the ring. NGC 3160 is a warped spiral seen edge on and is about 125,000 light-years wide. It appears, at least when seen edge-on, as a red spiral. Even the warped plumes off its ends are mostly red indicating no new star formation of any significance for millions of years. In fact, almost all members of the group appear to fall in the red and dead category.

NGC 3161, an E2 galaxy, is the smallest of the NGC galaxies in the group at only 57,000 light-years but does have an AGN core indicating it is still reacting to a likely interaction with another galaxy not too long in the past.

NGC 3163, Herschel\'s other discovery is quite large at a bit over 140,000 light-years and listed as an SA0-: galaxy rather than an elliptical.

NGC 3159, 3161 and 3163 appear to share a common halo indicating they may have had a close encounter with each other in the recent past. This may explain the large southern going plume coming from NGC 3159.

There are many other galaxies also likely members of the group. One without redshift data is east-southeast of NGC 3158, MCG +07-21-025. It isn\'t classified that I found and hard to observe as it is hiding behind a rather bright blue star. It makes it look like it is a red galaxy with a blue core.

The annotated image identifies all I found redshifts for. Only a few not members of the group. One star-like object is labeled RQ/G east-northeast of NGC 3158. RQ stands for Rejected Quasar. It apparently is just a very bright compact blue galaxy about 3.1 billion light-years distant. The Sloan image shows a slight blue disk around a bright nearly white core that is larger than a star of similar brightness. Likely it is some type of AGN, just not sufficient to be a quasar.

The minor planet center shows a periodic comet moving quite rapidly in the image but I see nothing at the position. It is 3.56 AU distant from us and 3.12 AU from the sun. One estimate puts it at 22.7 magnitude which would certainly be too faint at its speed and my lousy skies to have picked up.

Again this was a night of poor transparency though seeing was not good it was better than the previous night. Still, this image doesn\'t go as faint as it would under what used to be normal conditions here. The faint outer reaches of these galaxies is likely greater than I could see thanks to these less than optimum conditions.

I got one more blue image than normal because I thought one blue had been hurt beyond repair and so retook a blue image another night. Turned out I meant that comment for a different image so retook the wrong one. I used all three anyway.

14\" LX200R @ f/10, L=5x10\' RG=2x10\' B=3x10\', STL-11000XM, Paramount ME

Alternate Designation(s): 1RXS J101352.5+384536, 2MASS J10132633+3839277, 2MASS J10132910+3837115, 2MASS J10133412+3850356, 2MASS J10135052+3845536, 2MASS J10135283+3839160, 2MASS J10135507+3850343, 2MASS J10135919+3839260, 2MASS J10140712+3839092, 2MASX J10132629+3839273, 2MASX J10132910+3837113, 2MASX J10133414+3850355, 2MASX J10135049+3845536, 2MASX J10135280+3839166, 2MASX J10135502+3850346, 2MASX J10135920+3839256, 2MASX J10140714+3839096, 2MASXi J1013262+383927, 2MASXi J1013290+383711, 2MASXi J1013341+385035, 2MASXi J1013504+384553, 2MASXi J1013528+383915, 2MASXi J1013550+385034, 2MASXi J1013592+383925, 2MASXi J1014071+383909, 2MFGC 07928, ARK 234, ASK 340299.0, ASK 340302.0, ASK 340329.0, ASK 340335.0, ASK 340337.0, CALIFA 319, CGCG 1010.4+3855, CGCG 1010.5+3853, CGCG 1010.6+3906, CGCG 1010.8+3901, CGCG 1010.9+3855, CGCG 1010.9+3906, CGCG 1011.0+3855, CGCG 1011.1+3855, CGCG 211-019, CGCG 211-020, CGCG 211-021, CGCG 211-022, CGCG 211-023, CGCG 211-024, CGCG 211-025, CGCG 211-027, ECO 07858, ECO 07869, ECO 07880, ECO 07891, ECO 07902, ECO 07913, ECO 07935, ECO 07957, FIRST J101350.4+384553, FIRST J101355.0+385034, FIRST J101359.2+383925, GALEXASC J101326.25+383929.4 , GALEXASC J101329.20+383713.9 , GALEXASC J101334.23+385037.0 , GALEXASC J101352.82+383916.5 , GALEXASC J101355.00+385037.0 , GALEXASC J101407.28+383910.0 , HDCE 0570 NED001, HDCE 0570 NED002, HDCE 0570 NED003, HDCE 0570 NED004, HOLM 170A, HOLM 170B, HOLM 172A, HOLM 172B, HOLM 172C, IRAS F10109+3905, LDCE 0716 NED001, LDCE 0716 NED002, LDCE 0716 NED003, LDCE 0716 NED004, MCG +07-21-017, MCG +07-21-018, MCG +07-21-018a, MCG +07-21-020, MCG +07-21-021, MCG +07-21-022, MCG +07-21-023, MCG +07-21-026, Mr18:[BFW2006] 09736 NED01, Mr18:[BFW2006] 09736 NED02, Mr18:[BFW2006] 09736 NED07, Mr18:[BFW2006] 09736 NED08, Mr18:[BFW2006] 09736 NED09, Mr18:[BFW2006] 09736 NED10, Mr19:[BFW2006] 19935 NED01, Mr19:[BFW2006] 19935 NED02, Mr19:[BFW2006] 19935 NED05, Mr19:[BFW2006] 19935 NED06, Mr19:[BFW2006] 19935 NED07, Mr19:[BFW2006] 19935 NED08, Mr20:[BFW2006] 32030 NED01, Mr20:[BFW2006] 32030 NED02, Mr20:[BFW2006] 32030 NED03, Mr20:[BFW2006] 32030 NED04, NGC 3150, NGC 3151, NGC 3152, NGC 3158, NGC 3159, NGC 3160, NGC 3161, NGC 3163, NGC3150, NGC3151, NGC3152, NGC3158, NGC3159, NGC3160, NGC3161, NGC3163, NPM1G +38.0190, NPM1G +38.0191, NRGb 078.033, NRGb 078.034, NRGb 078.037, NRGb 078.043, NRGb 078.044, NRGb 078.045, NRGb 078.047, NRGb 078.048, NSA 058936, NSA 058937, NSA 058946, NSA 058948, NSA 136817, NSA 136869, NSA 158013, NSA 158015, NVSS J101355+385034, PGC 029789, PGC 029796, PGC 029805, PGC 029822, PGC 029825, PGC 029830, PGC 029837, PGC 029846, SDSS J101326.31+383927.5, SDSS J101329.08+383711.4, SDSS J101334.11+385035.5, SDSS J101334.12+385035.5, SDSS J101350.51+384553.6, SDSS J101350.52+384553.6, SDSS J101352.83+383916.0, SDSS J101352.83+383916.1, SDSS J101352.84+383916.1, SDSS J101355.11+385034.5, SDSS J101355.12+385034.5, SDSS J101359.18+383925.9, SDSS J101359.19+383925.9, SDSS J101407.10+383909.1, SSTSL2 J101359.14+383925.4, SSTSL2 J101407.07+383908.8, UGC 05511, UGC 05513, UGC 05517, USGC U288 NED01, USGC U288 NED06, USGC U288 NED07, USGC U288 NED08, USGC U288 NED09, USGC U288 NED10, USGC U288 NED11, USGC U288 NED12, UZC J101326.3+383927, UZC J101329.1+383711, UZC J101334.1+385035, UZC J101350.5+384553, UZC J101352.8+383916, UZC J101355.1+385034, UZC J101359.2+383926, UZC J101407.1+383909, WBL 258-001, WBL 258-002, WBL 258-003, WBL 258-004, WBL 258-005, WBL 258-006, WBL 258-007, WBL 258-008, [BFW2006] J153.37118+38.61983 , [BFW2006] J153.39215+38.84320 , [BFW2006] J153.46050+38.76490 , [BFW2006] J153.47013+38.65447 , [BFW2006] J153.47966+38.84293 , [BFW2006] J153.49662+38.65720 , [DZ2015] 756-01, [DZ2015] 756-02, [DZ2015] 756-03, [DZ2015] 756-05, [DZ2015] 759-01, [DZ2015] 759-02, [DZ2015] 759-03, [GMM2009] 0794570, [GMM2009] 0812816, [MGD2014] 1010.9+3905, [PJY2015] 588016892785590288 , [SUV2010] 869, [TTL2012] 011166, [TTL2012] 011167, [TTL2012] 252617, [TTL2012] 252620, [TTL2012] 252645, [TTL2012] 252646,