Saturday, November 18, 2000

Subjects of the Queen

Saturday the 18th of November was a reasonable day to try Pacheco State Park for a short night of observing. It must be at least six months since I'd been there, and recall being fogged out early on my last visit. This night would offer some good observing along with a fight against dewing and finally, cloud cover. But it was fun.

With temperatures in the 30's all evening, this was only the second occasion I can report ice forming on the shroud of my 18" Dob. Several of you will recall a similarly cold night at Fremont Peak within the past few years. However, sufficient clothing made the temps barely noticeable.

As the sky darkened, I pointed the scope up into Cassiopeia, where I would spend most of the night checking out subject of the celestial queen.

I began 1.75 degrees NNE of mag 2.2 Caph (Beta Cass). Residing in an obvious "V" formation of mag 5 and 6 stars that spanned almost 2 degrees in my finder, there sat what has recently been referred to as Mimi's Red Star. I believe it is mag 6.7 SAO 21020, one of the most colorful stars I've ever viewed. Along with the coppery look of a brand new penny, really intense, close by sat a whitish-blue star, creating a truly magnificent pair. Not far away is another copper star, not quite as intense, but also outstanding. This portion of the local Milky Way seems replete with copper and redder stars. Another good example of coppery stars is the "Pink Buddy" (which morphed into the "Pink Bunny" somehow), Eta Cassiopeia, as described by Jane Houston Jones. I literally could not get over the richness of the tones, and looked at Mimi's star for quite some time, inviting other observers to view it.

Having blown the fuse on my inverter, I put away my laptop computer and got out the Night Sky Observers Guide, Uranometria, Tirion's Sky Atlas 2000, notebook and assorted other references. It proved both challenging and fun to use paper charts. The 10 x 70 finder turned out to be my best friend, showing recognizable asterisms that allowed me to confirm my position, much like the zoomed in eyepiece views of star fields do when using The Sky on my laptop as a chart.

I observed several objects, but these few were the most interesting.

NGC 7635, the Bubble Nebula, was a challenge. Sitting very close to M52, the location is easy to reach. M52 is visible in a large finder. I had been through this area recently, hunting down open cluster Czernik 43, which essentially shares the field of view in my 20 Nagler with M52. Obtaining the orientation of CZ43 allowed certain determination of the direction to the Bubble. The nebula appeared as a glow 3' north of a bright star. Another bright star sat 10' SW of the first star. While visible at 100X without a filter, a UHC certainly helps. The nebula appeared somewhat fan shaped, with the thinner part of the shape toward the close-by star. The nebula may be viewed in part on page 521 of Burnhams, just off the dimmer of the two bright stars at the bottom right of the photo (the image shows M52, and although not mentioned, also contains CZ43).

Abell 82 (PK114-4.1) is a dim planetary nebula sitting close to the showpiece open cluster NGC 7789. I began by placing the cluster in my finder, and orienting myself on the wide pairs of bright stars that almost bracket it. One of the pair of doubles has a trail of stars coming off it, the other does not. A right angle off the solitary pair bring a pair of mag 5.6 and 6.2 star into view, and centered, offer the location of the planetary. Abell 82 appeared dim, with some stars involved, and somewhat elongated toward a bright star to its WWNW. While the UHC filter helped, the OIII did a much nicer job of brining out this rather ghostly object.

If I had thought Abell 82 was dim, the next one, Abell 84, made it seem an easy target. This planetary was larger, with a bright star sat 20' to its south, which helped pinpoint the correct location. I had expected magnification to help this planetary, but found it much easier to view at 100x than at 170. Perhaps that was a result of the filters... I have an OIII that fits my 2" 20 Nagler, but needed to use an 1.25" Ultrablock on the 12 Nagler. The planetary seemed roughly 5' in diameter and slightly out of round.

By this time temperatures were around freezing and my eyepieces would begin to fog when I got too close. I used a blow drier several times to defog. From here on out it was a fight against the elements.

I moved on to PK119-6.1, a small planetary, also in Cassiopeia. I don't recall how I found this one. But I do know that it was not easy, since the planetary is virtually stellar at lower powers. What did stand out was the star, at lower power, appeared rather green, causing me to stop on it. I increased power to 170X and it was still fairly stellar, but giving beginning to appear slightly round, like a shrunken Jovian moon. I took out the OIII and passed it between my eye and the eyepiece. The suspect star stayed bright, all others in the field dimmed. Bingo. It stayed bright while all the others dimmed more.

The last objects that were fun and presented some challenge were three galaxies situated between M31 and Alpha Cass, near three naked eye stars. NGCs 278, 185 and 147. I've seen these before, but I am always fascinated at the differences in three galaxies in such close line of sight proximity.

I found these galaxies by centering the 3 naked eye stars, SAO 36620 being the brightest of the three. Notice that two of the stars are closer together. This will help in star hopping the area, since two of the galaxies are quite dim.

NGC 278 is a bright yet compact round galaxy with a bright core, at magnitude 11.5, surface brightness (SB) 12.2, and 2'x2' in diameter. The core seems to diminish noticeably about 2/3rds of the way toward its periphery. The core is stellar. A bright star resides to the north of the galaxy. This galaxy sits on the opposite side of the naked eye stars from the other two.

NGC 185 is a large dim galaxy, but not such that you would not notice it. Its magnitude is 10.10, but its large angular size dims it considerably compared to 278. NGC 185's surface brightness is only 14.3, a large difference compared to 278. I estimated its size at about 10'x10', found it to contain a bright core and a possible hint of a spiral arm or some form of elongation along the object's western extremity. While 278 looked almost like a large bright planetary at first glance, 185 was a galaxy from the get-go.

Two groups of mirror-image stars separate NGCs 185 and 147. Each pair has a brighter component bracketing a dimmer one to the inside. Going through these stars from 185 to 147 seemed almost like passing through a portal, where the challenge factor suddenly increased.

NGC 147 is a ghost, with a magnitude and surface brightness of 10.5 and 14.5 respectively. Sitting further away from the 3 bright stars than NGC 185, this galaxy is large and amorphous. Perhaps it was deteriorating sky conditions, or a fogged eyepiece, this galaxy was a real challenge. It appeared to be about 8'x 16' and oriented N/S. I could detect what I wrote down as a bright core, but my memory is that nothing was bright.

Of these three galaxies, NGC 147 and NGC 185 are thought to be satellites of M31. In fact, their radial velocities are very close, 185 at -202 and 147 at -193, so they are heading toward us at about the same speed (the same distance away). I wondered if NGC 278 was another member, but its radial velocity is +640, so it is moving away.

Just as these three galaxies grew gradually dimmer and more challenging, so did the sky in general. By 11:30, we were packed up and ready to head out. All things considered, I am glad I went. Observing session for the next four months or more are iffy propositions at best, with an occasional surprise "great" outing thrown in. If you don't go out when you have a chance, it could be a long wait.

As I drove out of Pacheco, and pulled out onto highway 152, I remembered the sky's appearance. First timers were commenting how dark it had been. Yes, it did look dark compared to Coe or other nearby locations. But, clouds to the northwest and east held in some local light domes, leaving the really dark nights for another time. Pacheco in the right conditions can be the best of the local groups.

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