Observing more Hicksons at Lake Sonoma October 25, 2003

by Jane Houston Jones

We snuck up to Lake Sonoma on Sunday October 26 after spending an observing weekend at Mt. Wilson followed by an observing week in Las Vegas. :-) There were only two other observers there Sunday night, so we all had a perfect night to work on projects and compare views through our four (2 Dobs and 2 SCTs) telescopes. I worked on some Hickson Compact Groups of Galaxies for the Astronomical League's Observe Galaxy Groups and Clusters project, observing 8 galaxy clusters in about 5 hours of observing. We also observed Comet P2 Encke, and Mojo completed his Herschel 400 project.

Comet Encke was first discovered by French astronomer Piere Mechain in 1786, then in 1795 by Caroline Herschel, and again in 1805 and 1818, both by Jean L. Pons (1761-1831). It was Johann Franz Encke who, in 1819, was able to demonstrate that these four comets were identical; this was the second comet (after 1/PHalley which was established as periodic, therefore designated "2P". Comet 2P/Encke is the comet with the shortest known period of only 3.3 years (thus also the smallest orbit). This is its 50th observed return! Data Courtesy of SEDS. We observed it with the help of SkyTools 2 charts, Mojo's 14.5-inch f/4.8 Litebox, and a lot of patience. Luckily, there was a nice triangular asterism to guide us. We observed it twice, three hours apart to see if we could detect any motion. I found it in my 17.5-inch, too. We did verify the motion by sketching it twice against the background stars. We verified the motion on SkyTools afterwards, too.

Hickson 84 in Ursa Minor, RA: 16h 43m 53.8s Dec: +77 49' 54", 6 member galaxies, 2 seen. My eyepiece map from SkyTools 2 showed a nice triangle, and H84c is a faint oval smudge right next to a star in the triangle. H84c was the only other one seen. H84a PGC 58877 is mag 14.7, H84c PGC 58884 is mag 15.7. Paul Hickson notes that H84a is a radio source.

Hickson 88 in Aquarius, RA 20h 52m 34.1s Dec -05 44'40", 4 members, all 4 seen. This was my favorite of the night. I saw all four members. H88a NGC6978 is mag 13.2 and oval, H88b NGC 6977 is mag 13.2 and round with a hint of bar in the face-on spiral, H88c NGC 6976 is mag 13.9 and small, almost a stellar glow and H88d PGC65414 is mag 14.5 and a little slash of edge-on spiral light. This not only was a fun find but an easy starhop using my 80mm short tube 80 finderscope. At first look I could only barely glimpse anything here, but I spent a lot of time at the eyepiece and with time and patience, I was able to see the shapes. The AL booklet has images, which help in the identification. I think I showed this one to the other observers, since the magnitures were quite bright for faint fuzzies. H88a is a radio and infrared source and b has an irregular shape, and d is a weak radio source.

Hickson 1 in Andromeda, RA 00h 26m 12.3s Dec +25 44' 26", 4 members, 3 seen. H1a and b are close together, I saw b as a star next to the glow of H1a. H1a is PGC 1627 mag 14.4 and b is PGC 1625 mag 15. A line of 4 stars spans the eyepiece (and the SkyTools 2 chart) H1c glimpsed with averted vision on the other side of the star line. It's aka PGC 1618 and it's mag 15.0.

Hickson 93 in Pegasus, RA 23h 15m 35.5s Dec +19 00' 18", 5 members, 3 seen. The group is also Arp 99. A, b and c make a nice triangle of galaxies. H93a is NGC7550, a mag 12.6 amall fuzzy halo and bright core. H93b is the interesting one: NGC 7549, mag 13.2 smaller, in photographs the spiral arms show. Not in the eyepiece, tho. :-( H93c is NGC 7547 mag 13.9 oval. Did not see d and e.

Hickson 94 in Pegasus, RA 23h 17m 27.8s Dec +18 44'30", 7 members, 2 seen. Very close to H93. H94a and b are ellipticals called NGC 7578 a and b. Both are easy to see ovals mag 13.9 and 14.5 respectively, and are within an extended common envelope with a small spiral PGC 70916 which I did not see. These are the only two I could see. I wished I could see them all as they made a really nice zig zaggy line in Paul Hickson's book.

Hickson 95 in Pegasus RA 23h 19m 43.3s Dec +09 30' 48", 4 members, 3 seen. H95 a and c are connected by two spectacular filiments. Knots in these filaments correspond to regions of new star formation, says Paul Hickson. H95a is NGC 7609 mag 14.4 and H95b is called 7609b or PGC 71080 mag 15.3. I could see both of these and H95c too. It's PGC 71074, a slash of mag 15.2 edge-on. D not seen. I showed this one to the others who wanted to take a look.

Hickson 96 in Pegasus RA 23h 28m 09.9s Dec +08 47' 44" 4 members, 3 seen. This is also Arp 182. The bright H96a member is NGC 7674, a face-on spiral mag 13.5 I could tell it was a face-on spiral. H96c is close to A, a faint oval. Ray Cash's description that these look like a mini M51 is right on! H96b is NGC 7675, mag 14.5 All three seen with direct visionn. H96d not seen.

Hickson 10 in Andromeda RA 01h 26m 20.6s Dec +34 42' 44" 4 members, 4 seen. A great one to end the night with. Bright! H10a is NGC 536 mag 12.6. Elongated. It has a foreground? star visible. H10b is NGC 529 mag 12.7 more oval in shape. H10c is NGC 531 mag 14.1 round tight nucleus, H10d is NGC 542 mag 14.7 just a tiny wisp of edge-on elongation.

ObserverJane Houston Jones
DateOctober 25, 2003
LocationLone Rock Flat, Lake Sonoma, California 38 42 90N 123 02 43.7 W
Altitude1,129 feet - 75 degrees at midnight. RH 20% humidity
Instrument17.5-inch f/4.5 Litebox Reflector, named Hagrid Ocular 9mm Nagler type 2 for 222x
TransparencyLM 6.5 using LM area 6 Alpha Andromeda, Gamma and Alpha Pegasus and area 14 Epsilon, Eta and Gamma Cygnus