M 61 (NGC 4303) Galaxy in Virgo

Located at: RA 12 hours 21 minutes 55 seconds, Dec +04 degrees 28 minutes 30 seconds

Size: 6.5' x 5.7' Magnitude: 10.2 blue Class: SAB(rs)bc HII

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, 630 minutes (63 x 10 minute subs), 06/13/14/15/17/2011; seeing 2.1-4.0 FWHM per CCDStack

Processing:

CCDStack 2.24.4110.20701, Photoshop 7.0

Location:

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

Notes: M 61 was imaged with lots of moon and hazy conditions, and already past the meridian; however, I wanted to image it before it was gone for the season ... the two small galaxies to the north (above, west to east)) are NGC 4292 (1.7'x1.2', mag 12.2v, Cl: (R)SB(r)0^) and NGC 4301 (1.5'x1.2', mag 13.4b, Cl: SAB(s)cd).

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 4303
NGC 4303 = M61 = U07420 = MCG +01-32-022 = CGCG 042-045 = PGC 40001
12 21 54.9 +04 28 25
V = 9.7;  Size 6.5x5.8;  SB = 13.4

13.1": very bright, large, bright stellar nucleus.  Two spiral arms are faintly 
visible; one arm is attached S of the nucleus and winds towards the W and then 
N.  A slightly brighter arm is attached N of the nucleus and winds along the E 
side towards the S.  In the field with N4292 11' NW and N4301 10' NE.

17.5": two or three arms visible, interesting structure.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 4303
NGC 4303 = M 61 = h1202 = H I 139 is one of the few Messier objects to also
carry a number in WH's lists.  It also figures in the identification of NGC
4301, which see. - Dr. Harold G. Corwin, Jr.
Contemporary Visual Observation(s) for NGC 4292
NGC 4292 = UGC 07404 = MCG +01-32-016 = CGCG 042-040 = NPM1G +04.0344 = PGC 
39922
12 21 16.4 +04 35 44
V = 12.2;  Size 1.7x1.1;  SB = 12.8;  PA = 7d

17.5": fairly faint, small, bright core, slightly elongated halo.  Located 1.3' 
SSE of a mag 10 star.  Forms a close pair with N4292A 2' N.  M61 lies 11' SE.

13": fairly faint, small, slightly elongated ~N-S, brighter core.  A mag 9 star 
is 1' NW.

- by Steve Gottlieb
Contemporary Visual Observation(s) for NGC 4301
NGC 4301 = UGC 07439 = MCG +01-32-027 = CGCG 042-053 = (R)N4303A = PGC 39951
12 22 27.2 +04 33 58
V = 13.0;  Size 1.5x1.3;  SB = 13.6

17.5": fairly faint, fairly small, almost round, fairly even surface brightness.  
Located 10' NE of M61.  N4292 lies 11' NW.

13": faint, small, diffuse, slightly elongated, low even surface brightness.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 4301
NGC 4301 is one of the "classic" cases of a problem NGC object.  People have
been puzzling over it since LdR found it on 1 March 1851 with the Parsonstown
Leviathan.  Sue French just (May 2006) asked about it, so I am finally digging
into the records to find out what I can about it.  I must mention, too, that
Malcolm Thomson has made valuable contributions to this puzzle.  More on that
as we go along.

Here is the story:

In his 1861 paper, LdR has NGC 4292 and NGC 4303 listed together as having 
been observed five times.  He continues, 

  Sketched 4 times.  March 1, 1851.  [h]1196 [= N4292] is bM and has a vF 
  comp.; [h]1202 [= N4303 = M61] is a spiral, B. centre, and 2 knots.  There 
  is another neb. 10' nf.

Here's the first bit of confusion.  Is the nebula 10 arcmin northeast of N4292
or N4303?  LdR's note can be read either way.  I'll lay out some arguments
below suggesting that it is northeast of N4303 and not N4292 as many, 
including Dreyer himself, have supposed.

A second bit of confusion follows immediately, still apparently in the same
observation of N4292 and N4303:  

  About 84[deg] 34' N.P.D., and 12h 25m AR.  There is a scarlet * 10m. and a 
  F. E. neb. 10' s. of it, with *s in it.  See fig. 21, Plate XXVII.

This comment turns out to be totally unrelated to N4292 or N4303; it applies 
instead to NGC 4480.  But LdR finishes up this section of his Description 
with his note about the figure.  We should also note here that LdR 
misidentifies the figure, calling it "h1196" (N4292) while it is really M61.

Finally, he finishes the comments on N4292/N4303 with 

  April 9, 1852.  Last year's observations confirmed.  

So, LdR gives us two new nebulae in his 1861 monograph:  a very faint 
companion for NGC 4292, and another nebula 10 arcmin north-following either 
N4292 or N4303.  And he initiated a chain of confusion with his two errors and
ambiguous statements.

JH received the monograph soon after it was published, in time for him to scan
it thoroughly for the GC which he was then preparing.  His note in the GC 
shows that he took LdR's published description at face value:  

  [GC]2884 1202,a.  Under h. 1196 and 1202, two nebulae, unidentifiable, are 
  described as companions, but there must be some great error in Lord Rosse's 
  account of them, as the place of one is referred to a scarlet star "10' 
  south of a scarlet star R.A. 12h 25'[sic]."  Now h. 1202 is in R.A. 12h 14m.
  To afford a fair chance of reobserving them, the companion 10' nf h. 1202 is 
  entered here as 1202,a, and that south of the scarlet star, under No. 3060 
  as 1196, a."  

His entries in GC are credited as "R. nova?" and "R. nova"; respectively, so
he apparently placed greater reliance on the observation of the nebula south
of the scarlet star.

The next observers trying to find nebulae here were d'A and Schultz.  Neither
were successful.  d'A's note is in Latin, and is available elsewhere on the
Project's web site; Schultz merely says "GC.[sic] 2884.  Not a trace of it
discernible."

The next mention of the field comes from Dreyer himself in two notes in his 
1878 Supplement to the GC.  The first is for GC 2884 which became NGC 4301
itself:

  Not found by D'Arrest (Query, did he search "10' ad austrum" instead of 10'
  nf?).  Not seen by Schultz.  There is not any "great error in Lord Rosse's
  account."  The Nebula south of the scarlet star ([GC] 3060 was seen after
  h. 1196 and 1202 had been observed, probably while the telescope was being
  moved back to the meridian.

He is arguing that LdR's description is not at all misleading and that JH
simply misread it.  I'm siding with JH on this one; the comment about NGC 
4480 is simply out of place, and is too easy to read as JH did, and as I first
did.  It clearly needed its own entry in the 1861 monograph, just as Dreyer
gave it in the 1880 monograph (given below).

However one reads the note, Dreyer continues with another in the GC Supplement
that gives some further details on the interpolated observation:

  [GC] 3060.  To be struck out, = h. 1299 ([GC] 3032) [= NGC 4480], the star 
  is B. W. 12h 378 (Sch. red star 148).

JH and I would have appreciated having this information in the 1861 monograph.
Ahem.

The next information comes just two years later in LdR's 1880 monograph,
prepared, of course, by Dreyer himself.  Four observations are assigned to
NGC 4292 (GC 2870 = h 1196; in what follows, the square brackets enclose
comments by Dreyer, and appear just as I have typed them in here.  The only
exception is the degree symbol which I note as "[deg]"):

  1851, Mar. 1.  bM and has a vF companion [2' n by a diagr].
  1851, Apr. 21.  Another neb 10' nf.  [Entered as a nova (2884) nf h 1202 in
    the G.C., but nothing was found there by d'A. and Schultz.  The place 10'
    nf h 1196 does not appear to have been examined by anyone yet.]
  1861, Mar. 17.  (F Moonlight.)  About 15' p and 8' n is a F neb with a * or
    Nucl in centre and a * 8m close on its np side.
  1878, Mar. 28.  F, S, R, vglbM.  *9m Pos. 333[deg].7, Dist. 72".3.  16'+- n
    and 9'+- p is a vF object, sbM, most probably only a F *, it has a * 8.9m
    np v nr.  (IV. obs.)

Let's take these one by one.  The 1 March 1851 observation is correct as far
as I can tell -- the vF companion is 2.4 arcmin north of NGC 4292.  This is
the first of LdR's "novae" in this field that should have been in GC and NGC.

The 21 April observation probably applies to NGC 4303.  While there is a 
galaxy (UGC 7411, m_B = 14.9) north-northeast of NGC 4292, the actual distance 
is 11.9 arcmin.  This compares with UGC 7439 (m_B = 14.1) at 9.6 arcmin north-
east of NGC 4303.

On 17 March 1861, LdR says nothing about the galaxy itself, but notes another
faint nebula 15 arcmin west and 8 arcmin north.  There is nothing at all at
those offsets; in particular, there is no star 8 in the area.  The north-south
distance between N4303 and N4292 is 7.5 arcmin, so I wonder if this is an
observation of N4303 with a slightly erroneous description of N4292 -- which
does indeed have a brighter star "close on its np side."

Finally, Dreyer's own observation on 28 March 1878 is pretty clearly of N4292
-- except that again there is no object 16 arcmin north and 9 arcmin west with
a star 8-9 magnitude "np v nr."  Is this yet another garbled observation of
N4303, but this time mixed in with a real measurement of N4292 and its nearby
star (I measure a separation of 71 arcsec at a position angle of 335 degrees,
very close to Dreyer's more precise measures)?  The note "(IV. obs.)", by the
way, is just the total number of observations of the object.

This raises an interesting point about NGC 4303 (= GC 2878):  Dreyer has the
note "(VII. obs.)", but only lists three of them (again, his square brackets
aside from my "[deg]":

  1851, Mar. 1.  Spiral, 2 knots, centre B.
  1851, Mar. 7.  Drawn [P.T. 1861, pl. XXVII., fig. 21, both on the plate and
    in the G. C., p. 42, this figure is erroneously stated to represent h 
    1196].
  1878, Mar. 28.  Neby E ns, branch from s end turning p towards a * 13.14m in
    Pos. 254[deg].3, Dist. 70".9.  (VII. obs.)

All of these, including the correction to the figure captions, clearly point
to NGC 4303.  But where are the other three observations?  I've not been able
to find them in the published monograph.  If the observing notes of the third
and fourth Earls of Rosse are still extant, we might, however, be able to dig 
them out.

(Just to cover all the objects thoroughly, here are the 1880 monograph
descriptions on NGC 4480 = GC 3032 = h1299 = H II 531:

  1851, Apr. 21.  At 84[deg] 34'+- and 12h 25m+- I found a scarlet * 10m. and 
    a F, E neb. 10' s of it, with st[s] in it.
  1852, Apr. 9.  About 12h 23m and NPD 84[deg] 43' there is a ruddy (not 
    scarlet) * 10m. and a F neb. 10' s of it.  [As already pointed out by d'A,
    this neb is = h 1299 and the * = B.W. 12h, 378, Schj. red stars No. 148.
    G.C. 3060 is to be struck out.]  (II. obs.)

This is a fair description of NGC 4480 and HD 108849 = Tycho2 292-330, 
V_Tycho2 = 8.33, (B-V)_Tycho2 = 1.43, indeed a red star.  So, here at last is 
the information that JH needed to have in the 1861 monograph to correctly 
identify the object inserted willy-nilly into the descriptions for N4292 and 
N4303.)

At last, we come to the NGC where Dreyer's note reads 

  4301.  The place of 2884 is wrong in G.C., as the nova is 10' nf of h 1196
    and not of h 1202.  It was therefore not found by d'A and Schultz.

Dreyer adjusted the position of NGC 4301 appropriately, and most people have
taken the entry to point to UGC 7411.  

I certainly did this for years (e.g. the RC2 entry for N4310 is UGC 7411)
until Malcolm pointed out the inconsistencies and errors in LdR's two 
monographs.  So, I now think that the evidence points to UGC 7439 as the 
correct object.  It is twice as bright and considerably larger than U7411, as 
well as closer to N4303 than U7411 is to N4292 -- and therefore more likely to 
be noticed.  As for d'A and Schultz not being able to find it -- they were 
using 11-inch and 9.6-inch refractors, respectively.  These would allow them 
to dig out most of the Herschel's objects, but rarely objects discovered with 
a 72-inch reflector.

So, to summarize.  I think it is likely that Lord Rosse's garbled observations
point to UGC 7439 (sometimes called NGC 4303A in modern catalogues) as NGC 
4301.  I've put colons on this object's entries in the position tables.

However, it is just possible that Lord Rosse saw UGC 7411.  Even though this
is 0.8 magnitudes fainter, and half the size of UGC 7439, he could still have
run across it -- many of his discoveries are considerably fainter, including
the tiny galaxy just north of NGC 4292.  So, I've put U7411 into the position
table with question marks as a caution that this case is not entirely closed.
 - Dr. Harold G. Corwin, Jr.