M 105 (NGC 3379) Group of Galaxies in Leo

includes NGC 3384 (UGC 5911) and NGC 3389 (UGC 5914)

M 105 is located at: RA 10 hours 47 minutes 50 seconds, Dec +12 degrees 34 minutes 55 seconds

Size: 5.4' x 4.8' / 5.5' x 2.5' and 2.7' x 1.3' Magnitude: 10.2 blue / 10.9 blue and 12.4 blue Class: E1 / SB(s)0-: and SA(s)c

North is up

West to the right

Telescope:

 8" f5 Newtonian reflector

Camera:

  ST-8XME self-guided, binned 1x1, temp -20c, camera control MaxIm DL 4.56

Image:

Lumicon Red filter, 500 minutes  (500 x 10 minute subs) 05/1/2/3/ 2010; seeing 2.1-3.8 FWHM per CCDStack

Processing:

CCDStack 1.7, Photoshop 7.0

Location:

 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)

Notes:

The group is named after M 105 (centered, the large featureless E1 galaxy is the westernmost object in the field), the elongated SB(s)o-: NGC 3384 next largest to the east (left), and finally the little spiral NGC 3389 SA(s)c. This is a reshoot of a 260 minute red-filtered image from 05/2006 ... didn't gain much from doubling the exposure. This image was taken with no moon in the sky, but hazy sky conditions (see M 65 and M 66). See the 14.5" version.

The M 105 group is 48 minutes NNW of M 96, and 1.3 degrees NNW of M 95.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 3379

NGC 3379 = M105 = U05902 = MCG +02-28-011 = CGCG 066-018 = PGC 32256
10 47 49.7 +12 34 57
V = 9.3;  Size 5.4x4.8;  SB = 12.8

13.1": bright, very small bright core, slightly elongated.  First of three 
bright galaxies in the field with N3384 7.3' NW and N3389 9.7' ESE.

8": fairly bright, round.

- by Steve Gottlieb
Contemporary Visual Observation(s) for NGC 3384
NGC 3371 = N3384: = U05911 = MCG +02-28-012 = CGCG 066-021
10 48 17.0 +12 37 49

See observing notes for N3384.

N3771 was discovered by JH (h751) and described as "F, R. The second of 3 in a 
triangle."  Peters claimed an observation but this object was not recovered by 
Rosse, Schultz, Bigourdan or Reinmuth.  Just 1' W of Peter's position is a mag 
15.1 star at 10 46 57.5 +13 47 31 (J2000) and 1' S is a mag 14 star at 10 47 
01.3 +13 46 29 (possibly elongated on the DSS image?).  Carlson identifed N3771 
with a star based on Mount Wilson photographs.  But, in NGCBUGS, Corwin argues 
that the trio Herschel is referring to is N3379, N3384 (h751 = N3371) and N3389 
(h753 = N3373), as this trio matches the positions angles given in the 
observation of the first of the group.  See NGCBUGS for discussion.

- by Steve Gottlieb

NGC 3384 = UGC 05911 = MCG +02-28-012 = CGCG 066-021 = N3371: = PGC 32292
10 48 17.0 +12 37 49
V = 9.9;  Size 5.5x2.5;  SB = 12.6;  PA = 53d

13.1": bright, bright stellar nucleus, elongated 5:2 SW-NE.  Second of three 
with M105 7.3' SW and N3389 6.4' SSE.

8": fairly bright, round, moderately large.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 3384
NGC 3371 is probably NGC 3384, and NGC 3373 is probably NGC 3389.  His 
descriptions are appropriate for the galaxies, and his measured position 
angles -- 68.4 deg between his first and second objects, and 156.8 deg between
his second and third -- are a close match for those between N3379 and N3384 
(66.5 deg), and N3384 and N3389 (154.7 deg), especially when precession is 
taken into account.  

However, JH has left us positions that suggest that these are companions of 
NGC 3367, not NGC 3379.  His position for N3367, the nominal first of the 
three, exactly matches the position for that object measured on another night 
when the additional two objects were not seen.  Added to this is his 
observation of N3389 on the same night the two questionable objects were seen.
Even so, my feeling is that he has somehow confused his observations of N3367 
and N3379 on the night when he also measured the two companions.

Adding more mystery to the case is Peters's comment:  "N3371] was distinctly
seen by me 1880, Mar. 2; but 2198, the third of the `triple nebula,' could not
be found."  There are two faint stars within two arcmin of JH's nominal 
position for N3371; perhaps Peters saw one of these.  Dreyer notes in the GC
Supplement that no other observer had seen either N3371 or N3373 at JH's 
positions. - Dr. Harold G. Corwin, Jr.

Contemporary Visual Observation(s) for NGC 3389

NGC 3373 = N3389: = U05914 = MCG +02-28-013 = CGCG 066-022 = PGC 32306
10 48 28.0 +12 31 59

See observing notes for N3389.

Discovered by JH (h753) and described as "F, R, the last of 3 in a triangle."  
Not found by Bigourdan, Peters, Rosse, Schultz (who questioned whether this 
object and N3371 exists) or Reinmuth!  Identified by Carlson as a star based on 
a Mount Wilson photograph. A mag 14.7 GSC star is near JH's position but  Corwin 
feels there was a confusion on the first object in this "trio" which is actually 
N3379 and using the given position angles with respect to this galaxy, then 
N3373 = N3389 and N3371 = N3384.

- by Steve Gottlieb

NGC 3389 = UGC 05914 = MCG +02-28-013 = CGCG 066-022 = N3373: = PGC 32306
10 48 28.0 +12 31 59
V = 11.9;  Size 2.8x1.3;  SB = 13.2;  PA = 112d

13.1": fairly faint, very elongated 3:1 WNW-ESE, diffuse.  Third and faintest of 
three with bright galaxies N3384 6.4' NNW and M105 9.7' WNW.

8": faint, small.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 3389
NGC 3371 is probably NGC 3384, and NGC 3373 is probably NGC 3389.  His 
descriptions are appropriate for the galaxies, and his measured position 
angles -- 68.4 deg between his first and second objects, and 156.8 deg between
his second and third -- are a close match for those between N3379 and N3384 
(66.5 deg), and N3384 and N3389 (154.7 deg), especially when precession is 
taken into account.  

However, JH has left us positions that suggest that these are companions of 
NGC 3367, not NGC 3379.  His position for N3367, the nominal first of the 
three, exactly matches the position for that object measured on another night 
when the additional two objects were not seen.  Added to this is his 
observation of N3389 on the same night the two questionable objects were seen.
Even so, my feeling is that he has somehow confused his observations of N3367 
and N3379 on the night when he also measured the two companions.

Adding more mystery to the case is Peters's comment:  "N3371] was distinctly
seen by me 1880, Mar. 2; but 2198, the third of the `triple nebula,' could not
be found."  There are two faint stars within two arcmin of JH's nominal 
position for N3371; perhaps Peters saw one of these.  Dreyer notes in the GC
Supplement that no other observer had seen either N3371 or N3373 at JH's 
positions. - Dr. Harold G. Corwin, Jr.