Observing from Lake Sonoma - Sat 2/2/02

by Steve Gottlieb


I was surprised when I arrived at Grey Pine Flat above Lake Sonoma after sunset there were no other observers set-up. Though the forecast was for partially cloudy skies at best, conditions looked pretty good while I assembled my 17.5-inch dob and I was hoping some others would show up for what looked like a promising evening. Robert Leyland showed up as the winter milky way was starting to shine and quickly set up two small scopes he wanted to compare while I started observing with my 17.5-inch.

First up was supernova 2002ap in M74, discovered less than a week ago on January 29th. I had forgot to bring along the AAVSO finder chart, but knew the offset from the nucleus. Still there were two mag fairly bright stars (mag 12.5-13) around the location, so I simply sketched the stars a few arcminutes west of the core. When I checked at home, I was surprised the supernova was the brighter of these two stars -- perhaps mag 12.5 and apparently still brightening!

Next were a few easy planetaries that I hadn't seen in a few years, NGC 2022 in Orion and NGC 2346 in Monoceros.

NGC 2022 = PK 196-10.1 = PN G196.6-10.9 05 42 06.2 +09 05 10 V = 11.7; Size 29"x28"
17.5": immediately picked up at 100x as a very small, bluish-gray "egg" of fairly high surface brightness. Good contrast gain with OIII filter. At 380x (unfiltered), it appeared as fairly bright, clearly elongated SSW-NNE, ~27"x20". The surface brightness was irregular or mottled with a slightly brighter rim and darker center giving a weakly annular appearance. The rim seems to have a couple of slightly brighter spots and the ends of the minor axis slightly weaker. No sign of a central star.

NGC 2346 = PK 215+3.1 = PN G215.6+03.6 07 09 22.5 -00 48 24 V = 11.9; Size 60"x50"
17.5": easily picked up at 100x as a fairly small, round halo surrounding a bright mag 11.5 star. Nice view at 280x and 380x. The halo is irregularly round, ~50"x45" with a slightly uneven surface brightness and is slightly thinner or pinched on the NW side. Modest contrast gain with UHC filter at 100x-280x, although does not require a filter. The central star is the variable V651 Mon (mag 11.3-13.5), apparently near its maximum.

After quickly hunting down a few galaxies down in Caelum and Lepus, I took a look at a couple of the "nonexistent" RNGC clusters, NGC 2202 and NGC 2219 -- many of these "nonexistent" objects exist where the original discover placed them, but they're simply chance asterisms or denser star clouds in the milky way. Some actually look quite "cluster-like", though, in the eyepiece.

NGC 2202 06 16 51 +05 59.8
17.5": fairly distinctive asterism at 100x (20 Nagler), consisting of a bulbous mushroom-shaped ring of about a dozen fairly bright stars with a few others nearby. Within this irregular ring is a nice, mag 9.1/10.8 double (SAO 113671) at 10" separation. Adding to the effect is a straight trail of stars from the double forming a 10' "stem" heading to the NNE and containing a mag 8.7 star (SAO 113677). Listed as a nonexistent cluster in the RNGC.

NGC 2219 06 23 45 -04 40.6
17.5": at 100x, 15-20 fairly faint mag 13-14 stars and a few brighter stars are visible just following mag 6.7 SAO 133199. The group is elongated ~WNW-ESE and the stars are fairly evenly distributed. The SE corner is marked by a mag 7.5 star. Visually, this group appears to be a cluster as the star density is reasonably rich and the group is isolated in the field. Listed as a nonexistent cluster in the RNGC and not in the Lynga catalogue.

Although the relative humidity was quite high (my charts and eyepieces were getting moist) and the transparency was not the best, it seemed time for a bit more exotic fare. Abell 12, attached to 4th magnitude Mu Orionis is always fun to pick out from the glare of the star --

Abell 12 = PK 198-6.1 = PN G198.6-06.3 06 02 23 +09 39.1 V = 12.4; Size 37"
17.5": picked up at 100x and an OIII filter as a faint "knot" at the edge of the halo surrounding 4th magnitude 4 Mu Ori. Tried a variety of magnifications and filters and the most satisfying view was at 380x using a UHC or OIII filter as Abell 12 was cleanly resolved from the glare of the star (just 1.2' WNW from the bright star!). Appears round, ~30" in diameter, with a uniform surface brightness and a cleanly defined outer edge, though with better contrast away from the star on the NW side of the planetary.

An easier planetary, also nearly lost in the glare of a star is Sanduleak 2-21 near 4th magnitude 16 Puppis. Interestingly, this one was first classified as a galaxy (MCG -03-21-004), so sky plotting software may show both a planetary and a galaxy at its position! It was "discovered" as a planetary as recently as 1975.

Sa 2-21 = PK 238+7.2 = MCG -03-21-004 = PGC 22854 = PN G238.9+07.3 08 08 44.3 -19 14 02 V = 13.7; Size 40"x40"
17.5": very nice view at 280x using a UHC filter. The planetary is easily visible as a 40" well-defined disc. Best view with mag 4.4 16 Puppis just outside the western edge of the field which detracts from viewing. Sa 2-21 forms the NW vertex of a small isosceles triangle with two mag 11 stars 1.7' SSE and 1.5' ESE. No annularity was visible although the surface brightness was slightly irregular.

Sh 2-301 is an interesting HII region in Canis Major. Jane Houston had mentioned she had observed this object the previous evening, also from Grey Pine Flat and that reminded me to take a look again!

Sh 2-301 = Gum 5 = RCW 6 07 09.8 -18 29 Size 8x7
17.5": this is a surprisingly bright HII region at 100x with the OIII filter, situated just NW of mag 7.4 SAO 152499 -- as just a weak, undistinguished glow is visible unfiltered! The nebulosity tapers on the north side as it extends to and involves an easy trio of mag 12 stars (separation ~30" between neighbors). The eastern edge has the sharpest contrast with the sky as it extends roughly N-S. There was an impression of an extremely faint extension towards the mag 7.4 star, although this was not seen with certainty. Sh 2-301 then bends away from the star on the south side and extends toward the west for ~5' giving a triangular appearance. Nebulosity is weakest to the NW of the wide triple. Several other stars are involved within the glow.

UGC 3490 sounds like a galaxy, but its a strange knot of galactic nebulosity less than two degrees from the plane of the milky way in Gemini -- originally classified as a galaxy -- its probably still plotted as such on amateur software.

UGC 3490 = Weinberger 190 = IRAS 0603+1205 = NeVe 7 = GN 06.30.6 06 33 27.1 +12 03 32 Size 1.0x1.0
17.5": at 280x, a faint, very small glow was visible, ~15-20" diameter with a very faint, stellar or quasi-stellar core at moments. This galactic nebula was misclassified as a galaxy in the UGC, although it is located just 1.5 degrees from the galactic plane! Identified as a HII or reflection nebula by Weinberger, et al in 1995A&AS, 110, 269. Forms the SE vertex of a small isosceles triangle with two mag 12.5 stars 2.5' NNW and a similar distance WNW.

I spent some time on the huge HII strip, IC 2177 (Eagle or Seagull Nebula), which starts in Monoceros but heads south a couple of degrees, crossing the border into Canis Major. Off the northwest end is Gum 1 = Sharpless 2-292, surrounding a mag 7 star --

Sh 2-292 = vdB 93 = Gum 1 = RCW 2 07 04 25.5 -10 27 15 Size 20x20
17.5": at 100x, a very large, circular glow of low surface brightness is visible surrounding mag 7.1 SAO 152320 = BD-10 1848. Appears quite large, perhaps 15' in diameter with a vague hints of structure. The OIII gave only a very weak enhancement, but the H-beta filter noticeably improved the contrast at low power. This combination HII/reflection nebula is situated off the NW end of the huge winding IC 2177 strip which extends mostly to the south, and is a wonderfully rich region of the milky way with a number of clusters and star groups in the vicinity.

One of the last objects I looked at before the moon rose about 11:30 was Sh 2-176, better known as Barnard's Loop. This is really too large of an object to examine with my scope (I've had a good view with my 16x80 finder using an H-beta filter), but still it was fun just scanning around in the area northeast of M78

Sh 2-276 = Barnard's Loop 05 48.0 +01 00 Size 600x30
17.5": sweeping around the region west of the faint open cluster N2112 at 64x (31 Nagler) with a H-beta filter, a large swath of Barnard's Loop was quite evident extending through the 75' field. Once viewed with the H-beta filter, the "edge" can be seen and the region is very weakly glowing unfiltered at 64x, although much less contrast. Involved within this stream of nebulosity is M78 to the WSW of the open cluster, but I only followed the glow for a few degrees.

As the moon rose and illuminated the sky we could see thin bands of clouds around the sky -- still quite a rewarding evening.