FUZZY SPOT, October 2000, Delphinus
Delphinus is a small but very prominent constellation in the Fall sky. The tight "diamond with a tail" shape almost looks like a loose cluster, but in fact, it is not. The stars range from 100 to 950 light years in distance.
The pattern has been seen as many different animals. To the Greeks it was a Dolphin, the Babylonians a Pig, and to the Bedouin of the Arabian Desert, a Riding Camel.
Although the stars are conspicuous, the constellation is poor in deep sky objects. The Night Sky Observer's Guide (Kepple and Sanner) only list 14 objects, there are 3 Herschel 400 objects, and no Messier or SAC 110 Best of the NCG objects. So let's hope for good clear, steady, and dark skies when observing Delphinus
NGC 6891 (20h15.2 +12 42) We start out with 2 planetary nebulae. This one is quite small, pretty bright, slightly bluish, and has a star to the W. The UHC filter doesn't do much. It was seen as a fairly even glow with a slight halo. A very windy night when I observed this object, it might be better in steadier conditions.
NGC 6905 (20h22.4 +20 06) The second planetary is probably the best object in the constellation. Known as the Blue Flash Nebula, I saw it as pretty big for a planetary, somewhat bright, possibly elongated N/S but this may be due to fairly bright stars on the N, S, and E sides. It is not very well defined, no sharp edges, no real middle, it's pretty much a blob that fades out. The E side darkens up pretty fast while on the W, it fades more evenly and gradually. The size, shape, and star pattern make this a nice object.
NGC 6934 (20h34.2 +07 24) Now we leave nebulous objects and enter a multiple star object. At 100X, this globular cluster is somewhat small, pretty bright with a much brighter middle, round, no stars resolved, and barely granular. There is a star immediately to W. Increasing the power to 140X, granularity is definitely seen and the middle is possibly elongated N/S.
NGC 6956 (20h44.0 +12 30) Moving out of our Milky Way, we head to one of the faint galaxies in Delphinus. At 140X, it was very uncertain, seen as a stellar spot with halo around it and elongated E/W. It is very faint with a stellar nucleus or a possibly a foreground star, and an extremely faint halo. Using averted vision makes the object stand out a little. There is a group of stars to the N.
NGC 7006 (21h01.5 +16 11) Coming back into the Milky Way, we arrive at another globular cluster. 7006 is a very distant cluster, about 185,000 light years from Earth and 150,000 light years from the center of the galaxy. I saw it at 70X as somewhat bright, fairly small, round, and a little brighter in middle. I could see no granularity at any power.
PK 59-18.1 (20h50.1 +13 34) The last deep sky object is another planetary nebula, although a very faint one. In the 20" scope at 160X using the O-III filter, I saw it as very faint, very large, and round; basically a very slight brightening in the background. There are 5 stars involved, and another star to W which interferes with viewing this object. The object was unseen without the filter.
Since most of the deep sky objects are toughies, I decided to include a couple of double stars. These observations are from The Night Sky Observer's Guide by George Robert Kepple and Glen W. Sanner.
Kappa (20h39.1 +10 05) In a 4 to 6" scope at 100x: "Kappa Delphini is a pretty triple: the closer components appear yellow and the more distant member reddish."
Gamma (20h46.7 +16 07) In a 4 to 6" scope at 100x: "Gamma Delphini has a yellow primary with a green companion, the latter a rather rare stellar color. Some observers however see the companion as bluish. The spectral type suggests a true color for the companion of yellow-white: Gamma Delphini B probably appears greenish of bluish only by contrast with its deeply yellow primary."
Herschel 400 Objects
6905, 6934, 7006
SAC's 110 Best of the NGC Objects