A Short Night of Opens

After being deluged in the morning, looking at threatening clouds in the afternoon, calling off a trip to Montebello, and resigning myself to working, the sky opened for a few hours between twilight and 8 p.m.

I took the opportunity to give my 10" f/5.6 dob a breath of fresh air, letting the mirror cool and settle, while I ate dinner and watched darkness fall. I had printed out a backyard list a few nights before, and, putting on my winter coat, but leaving it open, went out to enjoy the cool of the winter night and hunt objects that I had left years before at the bright end of the Herschel list.

Since my list was sorted alphabetically, I began in Auriga. I knew it would be a short night, since the weather report was for clouding to come in just a few hours. So, in went my 19 Panoptic, out came my rarely used Tirion 2000, red light and micro-cassette recorder. I rarely record verbal descriptions of my views, but tonight I thought it would be a nice change, perhaps forcing myself to take better account of what I was observing.

My list is sorted first by constellation, from bright to dim., with the limit set at mag 10. All the objects in the first constellation were open clusters. I started with NGC2099, better known at M37. Located just off the imaginary line drawn from Theta-Aurigae and Beta-Tauri, and slightly "away" from Auriga, this is an easy target, and a spectacular one. This open cluster took up easily half the field in the 19 Panoptic. A bright star sits in the approximate center of the cluster, with a circular somewhat empty area extending away, meeting a wreath of dimmer stars that seem condensed and moving away from the core of the cluster. In some ways, this object looks like it has spiral galaxy-like arms leading to strings of outlying stars in the group. The field of view was completed by a few bright field stars toward the edges. It is a nice view!

Next on the list was NGC1960, M36. What a difference from one cluster to the next! M36 is much more sparse, but takes up about the same field of view as M37. I would guess it has half or fewer stars then the previous target, but more of them were bright than in M37 and fairly even in magnitude overall. The cluster appeared to have a significant number of pairs and some faint outlier. Between the first two clusters, my preference is M37, with many more embedded stars.

I moved just a bit toward the center of the constellation, stopping on NGC1912, M38. I would characterize this one as a mix of the prior two.... somewhat in between the sparseness of M36 and the density of M37. Watching for a bit, some dim components begin popping out of the background, encompassing perhaps three dozen fairly bright stars. The cluster took up over half the field of view. One nice aspect of viewing M38 is, off to one side is a small and dim cluster, NGC1907. The view of the two together reminds me somewhat of the great open cluster M35 in Gemini, and the smaller NGC cluster next to it. However, NGC1907 seems pretty dim, yet there, from in town. Funny, 1907 is described in The Sky (Bisque) as mag 8.19, and dense. Dense yes, but mag 8? I described it as a nice, tight smudge of stars, taking up at most a fifth of my field of view. Brightness sure depends on where you are viewing from!

Now I moved away from the big and bright (again, a relative statement)... moving away from the recognizable form of Auriga, toward Gemini. NGC2281 is in a rather empty portion of in-town sky. I worked off of Castor, Pollux and one of Gemini's arms to get to this object.. There are a couple of dimmer stars in the region that just barely popped in and out with averted vision, one being very close to the cluster. The cluster is about two thirds the size of Auriga's Messier objects, but it much poorer in number of stars. There are some dimmer components that are "strung out" away from what I would term the "body" of the cluster, with the cluster itself looking like a curved "V" shape, with the stringers of stars forming one long and one short leg off the body. The stars in this cluster are all about the same magnitude, and I detected many doubles. I would guess there are about 30 stars I could see in the group. When you find this cluster, there is no mistake about it, since there is not really much else in the area. This is quite different from looking for open clusters in the heart of Cepheus or other dense portions of the Milky Way! As for clusters, 2281 is really pretty nice and interesting.

I moved to NGC1664, magnitude in the mid 7's, just off the point in the "Kids" near Capella. For the uninitiated, the "Kids" are three stars very close to Capella. Capella, being the "goat star", has, according to mythology, its young offspring the "Kids", held in an arm of Auriga the Charioteer. Anyway.... 1664 is not hard to find, but it is not an outstanding open cluster. I had to sweep around several times before I was convinced I had found it. The cluster occupies about a quarter of my field of view, containing rather dim stars, with some very dim ones embedded in the group. The group looks V shaped, with two long, pronounced stringers of stars coming off it, along with a few bright field stars in my field. By the time I'd finished looking at this object, I found myself enjoying it, likening it to very fine sugar spilled on a dark black cloth.

I continued on to NGC1893. This cluster is "outside" the line described ngc 1893 by Theta and Iota Aurigae, nearby M36 and M38. I *like* this cluster! Not that it is spectacular in and of itself, because it is a mid 7 magnitude in town (dim), but even here, in my backyard, I can tell that it is embedded in nebulosity! Compared to the other fields I'd been viewing tonight, this one looks "grayer" and mottled. The cluster itself appears rather large, almost as large in total area as the Messiers in Auriga, but it is much more sparse with many, many dim stars. It appears the nebulosity is obscuring part of the cluster, resulting in the cluster appearing to be more of an arc of dim stars, with the nebula blotting out the core. While I was watching, a satellite went through the field, which was kind of startling. The cluster did seem to have a void in it's center, where the nebula was located. I'd like to look at this one with a good UHC filter. This whole area looks like it is rich in nebulosity, and just begging for a dark sky site for more exploration!

By this time, clouds were again appearing in the area, and objects were getting dimmer. I went back to the Kids, and jumped to the area where NGC1778 was supposed to be. I say supposed to be, because this one was getting into the difficulty of being an LX-200 object. I did find the cluster, and it was not spectacular, taking up about one forth the field at most. The stars were pretty even in magnitude, with possibly some less bright components, but it was so dim that it might be imagination rather than actual stars. There were a couple dozen stars in a tight grouping, some doubles in the bunch, and about five stars that are brighter magnitude than the rest.

By now, the sky was really beginning to cloud over. But, only two more objects in Auriga. HOLD THOSE CLOUDS! ;-)

I moved to a point between Alpha and Iota Aurigae, near a naked eye group of five dim stars to hunt down NGC1857. I did find it, but what a job! It is a rather dim in-town object. It revealed itself as being almost galaxy-like in smudginess (shades of the Herschel list mag 14 galaxies!), taking up perhaps a fifth the field of view. The stars are very dim, almost impossible to resolve into individual stars, although four or five brighter components do peek out from the haze. Both on the chart, and in the field of view, a brighter star stands close by. In fact, it is in the same field of view, being a nice bright white-yellow.

I took a break at this point and took my dog out front for a comfort break. Looking toward San Jose, I could see clouds moving in with no end in sight. Shortly thereafter, I packed up the scope, put it away in the garage, feeling satisfied that I got outside and pulled in a few photons for about an hour. I can't wait until the skies begin really clearing.

I sat down to write this report, and took another look out back. Perfectly clear. Winter is a fickle mistress for amateur astronomers.

Mark Wagner; last updated: 1998 Feb 18