Off the Beaten Path with Steve Gottlieb:
Spring Deep Sky Challenges
NGC 2366
07 28 55.0 +69 12 57
This galaxy holds the unusual distinction of containing an HII region that may be more prominent than the galaxy itself! William Herschel described NGC 2366 as "vF, vS, has a vF
branch nf". Looking at the photographic appearance shows the HII region is situated at the SW end with the main body of the galaxy as Herschel's "vf branch nf". So he was actually
describing the HII region with the "vF branch" the parent galaxy! Copeland later observed this galaxy at Birr Castle using Lord Rosse's 72-inch Leviathan and his description also places the
surrounding objects (stars and nebulous objects) with respect to the HII region. Most modern sources have incorrectly identified the large HII knot as N2363.
In my old 13-inch the galaxy itself appeared fairly faint, elongated 5:2 SW-NE, with a low almost even surface brightness. The unusually bright HII region is at the SW end of the galaxy
(2' from the center) and appeared as a "fuzzy" 12th magnitude star. Although very small it seemed elongated SW-NE and similar to a poorly resolved double star. An OIII filter will verify
this is an emission object.
Abell 33
09 39.1 -02 48
If you've never tracked down an Abell planetary, this one is a great introduction. The field is a snap to locate because Abell 33 has a mag 7.2 star (SAO 137026) embedded in the SW end!
With my old 13-inch f/4.5, the planetary spanned 4' and had a brighter rim using an OIII filter, giving a partially annular appearance. Although the planetary has a low surface brightness
and was missed by the visual surveys of the 18th and 19th centuries, it was visible with direct vision using the OIII filter and is a lovely sight in larger scopes.
This unusual reflection object consists of a binary star with a strong bipolar outflow which shows water ices (hence the name). This object caused a flurry of observations back in
1995 when it was discussed on the s.a.a. newsgroup. I took a look in my 17.5-inch and found an "out of focus" mag 11 star at 100x with a fainter mag 12.5 star just 0.9' NE. At 200x, though,
Frosty Leo was clearly nonstellar, ~10" in diamter and with a surprisingly high surface brightness. Upping the power to 280x and then 410x revealed a slightly elongated haze, ~12"x8"
oriented NW-SE and slightly flattened on the SW side.
UGC 5459
10 08 10.3 +53 04 59
This needle of a galaxy has a major:minor axis ratio of over 7:1. With my 17.5-inch, UGC 5459 appeared as a fairly faint, super thin edge-on, extended 4.0'x0.5' in a NW-SE
orientation with no central concentration. The view is very striking to the razor thin appearance and a mag 8.5 star just off the north side of the SE extension! The galaxy extends just
beyond this star and appears slightly wider and brighter at this end. The overall impression is a dagger hanging from the bright star as UGC 5459 tapers down even more at the NW edge.
NGC 3158 Group + Shkh 49
10 13 50.5 +38 45 53
This remarkable group consists of over a dozen galaxies surrounding NGC 3158 packed into a 25' field. The largest and brightest member, NGC 3158, was discovered by William Herschel
and should be easily visible in an 8-inch scope. With my 17.5-inch it appears as a fairly bright elliptical with a small bright core. The field is swarming with small, faint galaxies
including NGC's 3150, 3151, 3152, 3159, 3160, 3161 3163. All of these are visible in a 12 to 14-inch scope using moderate to high power in a dark site. Finally, there are several
challenging MCG and anonymous galaxies in the 16th magnitude range that are visible in a 17.5-inch scope.
Still looking for a more extreme challenge? Shakhbazian 49 is a very challenging compact group of compact galaxies situated just 20' NE of the
NGC 3158 cluster. This is a marginal object in my 17.5-inch. At 220x an extremely faint knot, perhaps 15", was glimpsed several times with averted vision, using a finder chart. At 280x,
there was a strong impression of two very close 16th+ magnitude stellar objects, though I couldn't view both objects simultaneously. Perhaps a 20 to 25-inch scope would be able to cleanly
resolve individual members.
Hickson Compact Group (HCG) 56
11 32.6 +52 57
A remarkable chain of galaxies, HCG 56 is located a mere 7' south of the bright barred spiral NGC 3718. Photographs reveal five members with the central trio appearing as an
interconnected chain chain. However, visually resolving the members should challenge even hard-core deep-sky observers. At 100x, this compact group merged into a faint elongated glow just
1' long, strung out roughly east-west with a 3-1 ratio. Increasing the magnification to 220x resolved a pair of knots: HCG 56b and HCG 56c. HCG 56a is the largest member of the group, but
this low-surface-brightness edge-on spiral required careful viewing. Observers using Lord Rosse's 72-inch reflector examined the field of NGC 3718 four times between 1852 and 1868 and
missed this galaxy chain, so just detecting this group should be considered an accomplishment.
Markarian 205
12 21 44.0 +75 18 38
Markarian 205 is quasar-like object that has been steeped in controversy over the years due to its possible connection with the disturbed galaxy NGC 4319. Since the early 1970's Halton
Arp has argued that deep photographs show a "bridge" of luminous material leading back to the main galaxy - in apparent contradiction to the standard intrepretation of redshift as a
distance indicator. I took another look last July at the Sierra Buttes, in the Gold Lakes Basin region of the California Sierras. Markarian 205 was visible as a mag 14.5-15 "star" less than
1' south of N4319. Although easily visible with averted vision, this object was fainter than recalled from earlier observations.
