OR Fall observing with the 48-inch
by Steve Gottlieb

Over the weekend of Halloween (October 30th), Howard Banich and I flew out to El Paso in the early afternoon, picked up a rental car and drove 3 hrs to Fort Davis in the remote Davis Mountains, site of the Texas Star Party. The weather had been cloudy earlier in the week but was predicted to clear up on the day of our arrival (Thursday) as well as Friday, but Saturday was listed as partly cloudy and Sunday was predicted to be cloudy and rainy. Still, as I've learned from several trips, the weather near Mt Locke is totally unpredictable as the Davis Mountains strongly affects any incoming systems. The good news around sunset was the skies were perfectly clear. The bad news was a consistent wind. We were able to observe for several hours, but it wasn't comfortable -- the scope was consistently bouncing in the winds, gusts would make observing high on the ladder uncomfortable - particularly when facing into the wind, and seeing was -- as Jimi likes to say "Variable to Terrible". I believe around 3:00, we finally gave up as there was no sign of the gusts letting up and the seeing was quite soft. Still we did get in some excellent views. The highlights from the first night included NGC 247 (HII regions), NGC 7793 (HII regions), and IC 349 (Barnard's Nebula).

The second night (Friday) was by far the best night and we observed to 5:00 in the morning, although the seeing was generally only fair. Highlights included resolving stars in M31 (NGC 206), NGC 7656, VV 186 = Arp 249, Taffy Galaxies, Arp 251, NGC 891, Taffy II galaxies, Arp 78, Zwicky's Triplet, Zwicky's Boomerang, Cas A. The last object we took a look at Comet ISON, which was pretty impressive in the 48-inch, although still 8th magnitude and very low. The third night (Saturday) was clear though a tropical system was expected to arrive late at night. The seeing, though, was fair at best and often poor and around 3:00 we started seeing evidence of the front arriving. Highlights included the AM 0003-362 chain (5 galaxies), Burbidge's Chain, Arp 67 (triplet), Arp 295, Eridanus Cluster (globular), NGC 6670 and the filamentary structure in M1.

Sunday was cloudy as predicted, but Jimi, his wife Connie, Howard and I took a road trip south to spectacular Big Bend National Park. We also had a scenic drive along the Rio Grande river, including a visit to Terlingua, which had just hosted the 48th annual International Chili Cookoff competition the day before.

NGC 247 spanned at least 18'x5' NNW-SSE, stretching from an HII region at the NNW tip to beyond a mag 9.5 star near the SSE end. An interesting feature is a very large, elongated darker (dusty) region dubbed the "Needle's Eye" on the NNW side, extending at least 3.5'x1.0'. A relatively bright HII knot (identified in NED as MRSS 540-038059 from the "Muenster Red Sky Survey") is beyond this feature, 9.5' NNW of center. It appeared fairly faint, relatively large for an HII region, elongated ~N-S, 20"x12". A second well-defined HII knot is MRSS 540-038506, found 5' NNW of center. This easy patch appeared fairly faint, elongated, 15"x10". At least two small knots (including MRSS 540-038001) are on the SW side of the halo ~2.4' from center and ~1.5' E of a mag 12-12.5 star just off the west edge of the disc. Finally, I picked up a faint, very small knot, ~6" diameter, situated 3.5' SSE of center and 1.1' N of a mag 13.5 star. This HII region (not in the MRSS) forms a "double" with a mag 15 star 15" N.

NGC 7793 is a bright showpiece galaxy in Sculptor, very large, oval 3:2 E-W, ~7'x4.5', large bright core. Spiral structure is evident, though it was difficult to trace individual arms except for one better defined arm attached on the west side of the core. This arm sweeps towards the east on the south side of the core (~2' from center) and ends just east of center. The halo is lumpy with an irregular surface brightness and several HII knots/associations are visible. The brightest individual knot is [H69] #20, from Paul Hodge's 1969 paper "HII Regions in 20 Nearby Galaxies", a fairly faint, 10" knot that was easily seen 1.5' S of center, near the south side of the halo. [H69] #27, a slightly smaller and fainter patch is near the WNW end of the halo (1.9' from center). On the WSW side of the halo are two additional close, faint knots, both ~8" in diameter; [H69] #32 situated 2.3' from center and [H69] #33 at 2.4' from center. Finally, [H69] #3/#5 is a fairly faint, 15" patch near the NW edge of the halo, 2.8' from center. A mag 12.5 star is just off the northern edge, 2.9' from center.

We examined the large association NGC 206 carefully for resolved stars using the finder chart in Stephen Odewahn's 1987 study "A photometric survey of the rich OB association NGC 206 in M31". The 6 or 7 brightest members down to V = 17.6 were carefully identified with the brightest member #12 (V = 16.1) at the north edge relatively prominent. Then just scanning over the cloud with averted vision, roughly 20 additional extremely faint stars popped in and out of view, mimicking the appearance of a partially resolved globular cluster! Based on photometry in the paper, these extended down to approximately V = 18.3-18.5. The cloud, itself, was quite irregular and split up into several slightly brighter patches. I've labeled some of the brighter members which were individually identified on the chart.

NGC 7656: at 488x and 610x appeared fairly faint to moderately bright, round, ~24" diameter, high surface brightness. Surprisingly, a low surface brightness wing or loop extending to the northeast was immediately noticed. This loop is brighter along the northern edge and passes through a mag 16.7 star (or stellar galaxy), increasing the overall length to 45" extending southwest (core) to northeast (loop). A mag 16.5 star lies 1.3' W and another mag 16.5 star is 1.4' N. 2MASX J23242536-1902139, an extremely compact galaxy (V = 15.7) lies 1.9' NW. Finally, 2MASX J23243030-1903019, an extremely faint quasi-stellar galaxy was glimpsed less than 30" NNW, although another loop in that direction was not seen.

VV 186 = Arp 249 was clearly resolved into two cores at 488x, encased in adjacent halos. VV 186b, the southwestern galaxy, appeared moderately bright, very small, round, 10" diameter, high even surface brightness. Forms a very close pair with VV 186b, just 12" between centers. A mag 17 star is off the SW side [18" from center]. VV 186b, the northeast component, appeared fairly faint, small, round, very small bright core surrounded by a very small halo. An extremely faint and small glow was detected (part of a plume or jet on images) off the east side [18" from center]. UGC 12914/12915 = Taffy Galaxies lies 35' NNE.

UGC 12914 and 12915, known as the "Taffy Galaxies" was observed at 610x. UGC 12914 (southwestern component) appeared bright, fairly large, very elongated 3:1 NNW-SSE, 2.1'x0.7', sharply concentrated with a very bright, rounder core. The southern end of the galaxy gradually faded out and extended further than seen with my 24". A dust lane creates a sharp light-cut off on the east side of the core and the diffuse glow from an arm is visible further east. A bright curving spiral arm is attached on the NNW side of the core and it hooks north counterclockwise towards the companion UGC 12915. The arms from both galaxies nearly merged in an embrace, but did not connect. A mag 13 star is just off the SE end. UGC 12915, smaller, northeastern component appeared fairly bright, moderately large, very elongated 3:1 NW-SE, broad concentration. Appears asymmetric with an arm on the north side bending west and then dimming out as it hooks slightly south.

UGC 813 and 816 are a second "Taffy-type" Galaxies in Andromeda. UGC 813 appeared moderately bright and large, elongated ~5:2 WNW-ESE, ~0.6'x0.25', contains a small brighter core. At higher power the galaxy appears asymmetric, with the arm on the WNW side dimming to a low surface brightness but extending noticeably further than the ESE arm and increasing the major axis to 0.8' or 0.9'. A mag 16 star is superimposed near the ESE end. UGC 816 appeared moderately to fairly bright, moderately large, very elongated 5:2 or 3:1 roughly N-S. Well concentrated with a small bright core that increases to a quasi-stellar nucleus. Extending from the central "bar" are the beginning of spiral arms; the northern arm fades rapidly as it curves sharply clockwise to the west towards UGC 813, its interacting companion. The southern counterpart is fainter, but bends easterward with the total length to the ends of the arms ~1.0'. A number of mag 10-15 stars litter the field. The neighbor CGCG 551-011 = KTG 4A appeared moderately bright and large, very elongated 5:2 or 3:1 SSW-NNE, 0.8'x0.3', contains a small bright core.

Arp 251 is a very compact triple system in western Cetus that was viewed at 610x. MCG -02-03-037, the brightest member and NE component appeared fairly faint, very small, slightly elongated ~E-W, ~18"x14". These dimensions refer to the core and with more careful viewing, very low surface brightness extensions N-S were seen. Two very faint companions lie 24" SSW and a similar distance SE. In addition, a mag 15.5 star is just 14" W. So, these four objects fit in approximately a 30" circle! Located 4.3' NNE of mag 7.5 HD 5202 and a mag 13.5 star lies 1' S. 2MASX J00534765-1351358, the second brightest component lies 24" SSW and appeared very faint, very small, round, 10" diameter. APMUKS(BJ) B005119.43-140753.8, the faintest component (though not difficult), lies 26" E of the 2MASX galaxy and also appeared very faint and small, round, 10" diameter.

The brightest member of Zwicky's Connected Triplet appeared moderately bright, fairly small, round, 30" diameter, small bright core with a quasi-stellar nucleus. Flanked by a "fairly faint" companion 25" SW, which appeared fairly faint, small, round, weak concentration, 12" diameter. An "extremely faint" 18th magnitude companion is 30" ESE (SDSS J164931.14+452731.8), though this galaxy is not part of the Triplet. The third component, MCG +08-31-003a, lies 2.3' NNE and appeared fairly faint, small, round, 18" diameter, very small bright core, faint stellar nucleus. At mag 13 star lies 27" NNE. Finally, 17th magnitude PGC 2265793 lies 3.3' NE.

At 375x, Zwicky's "Boomerang" galaxy appeared as a very faint, fairly small, thin boomerang shape, elongated E-W. The galaxy curves in perhaps a 120° arc, concave to the north. Although the galaxy has an fairly even, low surface brightness with no core, the western tip is slightly brighter. A mag 16.5 star is barely off the east tip. Increasing the magnification to 610x and then 813x provided an excellent view. The Boomerang appeared mottled or slightly lumpy and was brightened slightly at both tips. There was a strong impression of several stellar quasi-stellar knots along the length. The mag 16.5 star was cleanly resolved off the eastern side. This galaxy is extremely blue with emission knots, and may be an extreme starburst galaxy.

This N-S galaxy chain in Sculptor of length 3.4' is classified in the Arp-Madore category of "Interacting Quintets" and displayed in the Atlas (full page) in section 5.1. All 5 members were resolved at 375x and 488x. ESO 349-27 is the brightest in the chain and appeared fairly bright, moderately large, slightly elongated N-S, sharply concentrated with a a very bright core. The halo is much fainter and increases in size with averted vision to ~40"x32". A mag 15.5 star is superimposed on the northwest side of the halo. ESO 349-26 NED1/NED2/NED3 lie ~1.5' N and PGC 131846 is 1.8' S. ESO 349-26 NED1 is the brightest in a tight triple at the north end of the chain and appeared fairly faint to moderately bright, fairly small, round, ~24" diameter. A mag 14.5 star is barely off the NE side, 18" from center. ESO 349-26 NED2, just 35" E, appeared faint to fairly faint, small, 20"x15" (the very low surface brightness arms were not seen). ESO 349-26 NED3, 0.5' S, is very faint to faint, very small, round, 12" diameter. Finally, PGC 131846 at the south end, appeared faint, fairly small, round, 25" diameter, fairly low surface brightness with only a broad, weak concentration. A mag 14 star lies 1' SW.

NGC 6670 in Draco is a fascinating interacting pair seen in this HST image. At 488x and 813x, NGC 6670B, the western component, appeared as a moderately bright, very thin edge-on, 5:1 WSW-ESE, 0.6'x0.12'. NGC 6670A is the brighter eastern component and was slightly detached (perhaps by 12") from the western component. At 488x it appeared moderately bright with a high surface brightness, very elongated 3:1 WNW-ESE, 0.6'x0.2', contains a bright elongated core. An extremely small knot is at the ESE tip. Using 813x, this knot (listed separately in the UGC notes, but probably a compact star forming region in NGC 6670A) occasionally was just cleanly detached, round, ~5" diameter, situated barely south of the major axis. A mag 12.5 star lies 1' ESE of the eastern component and CGCG 301-32 is 5' SE. Located 4.4' due E of mag 9.0 HD 238901.

The supernova remnant Cas A was one of the highlights this trip on the 48". We used 488x and a NPB filter to examine this SNR carefully. Immediately I noticed the nebula was much more extensive and detailed than previous views. The glow extending roughly 2.4'x0.8' E-W (twice the size seen previously) with the brightest section on the eastern half. At the west end the nebulosity faded and thinned as it curved WSW of a mag 13.5 star. The eastern half was quite irregular and brightest near the eastern end, where a couple of stars are involved. A very faint, but distinct filament (not seen previously) is attached at the east end and also extends E-W, just south of the main section by ~30". Overall, Cas A had a weak filamentary structure as opposed to a smooth glow, mimicking a piece of the Veil Nebula through a small scope. A short section of the southern rim was probably glimpsed, though I wasn't 100% certain of the observation (Jimi and Howard were).