SSPM11. Pegasus - Triangulum
By Scott Mellish, 1997
Stephan's Quintet happened to be a small group of galaxies I had been hoping to observe for quite some time. New moon weekend at Wiruna provided the occasion on the 29th August, 1997. The constellation of Pegasus was nicely placed by 1.20am and I turned the 16 inch, and located the grouping without too much trouble. With a 9mm Nagler in place the five small featureless galaxies were fairly visible considering they were well towards the north. As shown in Sketch 1, Stephens Quintet is a challenging group of small fuzzy blobs with no discernible features of any merit. At 210x, with a pretty average sky, the Quintet still managed to hold my interest for some time as the small fuzzy objects looked nice together especially with the central pair so close to each other. Once can imagine what sort of interaction is at play here. The 23' field also had a nice smattering of foreground stars that contrasted well with the objects.
The Quintet also appears to be a bit of an enigma as measurements show the galaxies to have widely discordant red shifts which could conclude in one theory that we may be seeing an expanding or exploding group. All this aside though, Stephens Quintet is a novel group to observe. NGC 7317 is at mag 13.6 with NGC 7318 being 13.4, NGC 7318A at 13.4, 7320 at 12.6 and 7319 at 13.1.
|Sketch 2 shows NGC 598 (M-33) the well-known and lovely face on spiral in Triangulum.
A nice eyepiece with a fairly wide field is the go with this object as its overall surface brightness is not very high. Using a 22mm panoptic eyepiece at 86x gave a nice full field view of this object which is a treat to look at. Starting at the top of the field we see a faint round smudge which is a nebulous region of the galaxy very similar to the Tarantula Nebula and is perhaps one of the largest H-II regions known in any galaxy. Recent Hubble Space Telescope shots of this region are awesome, but also very humbling for amateurs trying in vain to discern the most objects, I'm getting a bit of the track here so I'll get back to NGC 598.
Just below the small oval shaped H-II region at top, we follow a lovely soft wispy spiral arm as it arcs towards the large dense core glowing within a soft ghostly halo. To the left, we pass the core and catch another spiral arm which arcs down towards the bottom of the field. Two fairly bright clumps towards the top of the lower spiral arm show well in the eyepiece and the faint ghostly haze that merges the clumps into the galaxy itself appears ever so slightly in the eyepiece to be the hint of further spiral structure. At first glance this object does not show too much detail, but after a few moments careful observing, the subtle spiral arms show some structure and time at the eyepiece can be spent studying this delightful object.
NGC 598 is known as the Pinwheel Galaxy in the Northern Hemisphere and is more than likely the closest spiral galaxy after M31 in Andromeda.
NGC 598 is best observed at low power with a wide field eyepiece, being a large surface brightness object, contrast is all important for a pleasant view of this object.