Saturday, October 30, 1999

Dogs, Hicksons, AAA and time warps

Saturday the 30th of October, TAC went to Pacheco State Park for a short night of deep sky observing. Moonrise was minutes before midnight, but conditions were so nice for an end of October that we had a very good turnout, and an enjoyable evening.

There were two mishaps worth noting, one before observing and one after. The before involved my 18" Obsession, and a neighboring property owner's dog. The canine marked his territory on the side of the scope's rocker box. What a shock to turn around and see a leg-raised dog in mid-relief. I cut his actions short by instinctively yelling an unusually profane command, which the dog obeyed, running off at full tilt.

My friends, enjoying the spectacle, suggested that I should mark over the dog's claim, in order to reassert my ownership. No way.

As the sun set, them temps dropped, but soon settled into a comfortable fall evening. By dark, the Milky Way was overhead and the hum of pre-observing activities settled into the quiet of dozens of observers doing what they came for. It was a really pleasant evening.

We were also surprised by Rich Neuschaefer and Jay Freeman showing up in new vehicles that were much more astro-friendly than either's previous ones. Rich handed out mortar-shell sized ice cold Fosters, which we all enjoyed, and Jay pulled out two delicious large pizzas!

The largest aperture we had on-site was a 25" Obsession. There were several 18" scopes, a 17 or two, a 16", 14.5" StarMaster, multiple 12.5" inch, various sized SCT/LX-200's, a 6" Takahashi and more. I could not keep up counting the people and scopes in the area by true dark, but there were at minimum 25 scope.

My program for the evening was to continue in the Pegasus entries on the SAC database. It was to be a relaxing, slow-paced session for me. One observer logged some 80+ objects for the night in his 16" Dob, mostly on compact galaxy clusters, but I spent quite a bit of time talking to other observers, looking in other scopes, and letting my observing buddy catch up to me (or try anyway.... he's jumped into the deep end with little star hopping experience, so it takes a bit of time to develop the skill). Here are my finds for the night. I used an 18" Obsession with two oculars, a 20mm Nagler and 12mm Nagler. My star atlas for the night was Software Bisque's current high-end version of The Sky for Windows.

NGC 7568 is a round galaxy that Dryer described as extremely faint, pretty large, irregularly round and with several stars involved. The Sky lists it at mag 14.5, with SAC showing mag 13.5 with a 12.6 surface brightness (sb). I found it faint, small and rather unremarkable. It is under 1 arc-minute in size, elongated slightly E/W. It sits about 14 arc-minutes NE of a mag 8 star that is the closest in an easily identifiable chain of 5 stars. Another bright star, mag 6.5, sits 20 arc-minutes N. Find this object by placing your Telrad circles inside the NW corner of the Great Square of Pegasus. Three naked eye stars in the mid to high mag 4 range are visible there. Use those to orient your Telrad.

Next was NGC 7624, UGG 12546 and UGC 12545. Dryer says it is a round galaxy, very faint, little extended or irregularly round, diffused, very little brighter middle and shines at magnitude: 13.4. SAC is close at mag 13.1 with sb at 12.6. This, while dim, is not difficult to locate since the 2 degree circle on the Telrad lies just S of the Great Square line from Scheat to Alpharatz. While difficult to detect the galaxy, there are some distinct star patterns that give-away the correct location. About 26 arc-minutes WWNW of the galaxy lies a bright pair, at mag 6.4 and 7, the brighter one closer to the galaxy. Forming an arc N-S on either side of the mag 6.4 star is an easy chain of dimmer stars. Between the mag 6.4 star and the galaxy, slightly off-line to the N is another bright star, mag 7.6. Using those guideposts, you should be able to pinpoint the galaxy's location. ESE of NGC 7624 by about 10 arc-minutes is a parallelogram of stars, two brighter one on the galaxy side, two dimmer away. Roughly 10 arc-minutes further ESE, barely visible was UGC 12546 and UGC 12545. I confirmed these by identifying a very tight triangle of stars almost N of the galaxies. The brightest of the three stars was closest to the galaxies, dim at mag 14. A third UGC galaxy in the group eluded me.

NGC 7056 sits alone in the eyepiece. At mag 13.8 (The Sky), it is not difficult to perceive as a smallish round glow. There are not many identifier stars in the field, but very nearby, maybe 30 arc-minutes S, is a distinct pattern of four bright stars with a few nice yet dim straight chains involved. These will help confirm the correct field. Some observers will find the locating the piece of stellar real estate to hunt a challenge. It is in the middle of the empty sky between Enif (Pegasus' nose star) and the eastern wing star in Cygnus - 53 Cygni. In fact, you should note a mag 4 star between them. That star is 1 Pegasi, and should be touching the northwestern 2 degree Telrad circle.

NGC 7347 is probably in the easiest location of any target I looked at. Find Pegasus' neck, and note the bright star between Markab (beginning of neck) and Biham (end of neck). That star, is called Homam, easy to see at mag 3.4. The target galaxy is right there, such that the inner 30 second Telrad circle's east edge touches the star. The galaxy is described as extremely faint, pretty large and elongated. There is another galaxy in the field, but too dim for me this time. I found I needed to confirm star fields to make sure I was seeing NGC 7347. About 16 arc-minutes N of the galaxy is a chain of stars, one mag 10, another mag 11.4. There are distinct doubles in that chain. There is also a mag 10.8 star 6 arc-minutes to the NE.

NCG 7461, NGC 7463, NGC 7465, NGC 7448 and NGC 7464. This galaxy field is fun. There are plenty of bright mag 9 stars to use as references when star hopping in the eyepiece, and the galaxies are fairly easy to pick out. NGC 7461 et-al are in an even easier to locate naked eye position than NGC 7347 (which now moves to number two in ease of locate ratings for the night). If you can find Markab, you can find NGC 7461, as it is one degree west of the bright star. NGC 7461 is small and, at mag 14.3 (SAC 13.3 and sb 12.7), not too difficult to pick out as its fairly compact. It sits 4 arc-minutes W of a mag 11.7 star. Three mag 10 stars are W and SW of the galaxy about 20 arc-minutes. To the north, you should see a mag 8 star. Find it and you've found NGC 7463, NGC 7464 and NGC 7465. It is easy to see NGC 7465 and NGC 7464, since they are large and close to the bright star. NGC 7464 is particularly nice, although dim at mag 14.27, it is an edge-on about 1x4 arc-minutes in size. I could tell there was something unusual about the object, so in went the 12 Nagler, and out popped NGC 7463, small and perpendicular to NGC 7464 on its S side. About 20 minutes W of this group was NGC 7448, very easy to see and quite large at mag 12 and 2x4 minutes size.

During all this, I was wandering around, helping confirm a star field here and there, peeking through other scopes, having a few coffees, chatting about clubs, equipment, observing sites and anything else that typically comes up at a star party. I began to head toward the restrooms when I noticed the 25" Obsession aimed in the direction of the Veil. I climbed up to find it on NGC 6990, along the "Witch's Broom." I could see the difference aperture makes. My 18" does very nicely here, but the 25 had more "pop" as I was seeing definite structure within the tubular shape of the ribbon of nebula. It was a very good view.

Sometime during the night I was also called over to Steve Gottlieb's scope, to have a look at a very nice planetary ring-nebula in Grus. This was a very low object, but Pacheco State Park has a very good low and dark southern horizon. At about 100x, the object looked like a dead-ringer for the more well know Ring in Lyra. It was big and bright. He also showed a great view of a diffuse nebula in Cepheus, near NGC 6946, but I do not recall the numbers. Perhaps he'll chime in here and fill in the blanks.

The night was getting along, and midnight was too close. I pressed on with NGC 7485. It is a mag 14 round galaxy with a bright core. It's location is tricky. I had success reeling this one in by using a chain of stars that hook off the belly of Pegasus, between Scheat and Alpharatz. Coming from Alpharatz toward Scheat, you'll note a chain of three or four stars, all in the 5's mag-wise. By imagining the first three continuing out, I could see the position should be 2 degrees beyond where the temporary imaginary star would be. This landed me almost dead-on the target. This was not easy, since I tried perhaps three other methods to locate it first. The galaxy was small and dim, seeming to have some elongation NW-SE, but it was subtle. A chain of bright stars ran NE/SW to the NW of the galaxy, about 5 arc-minutes away at its closest point. The brightest star was at the W end of the chain, and was the center point of a small but distinct chain of stars. Another chain of stars helped confirm, running E-W of the galaxy, to its NE. This was a pleasant field to confirm, since there were so many identifiable star patterns in the field.

The last galaxy I went after was NGC 7558. This turned out to be a really nice surprise. The first thing I noticed when preparing to track it down was a difference between the reported magnitude in The Sky (says mag 16.0), and the SAC database which catalogues it as mag 14.9 but sb of 12.7. I did not think I'd see mag 16 that night. I moved the scope to the area just inside the square near Markhab. A mag 5.8 naked eye star was blinking in and out of view, but I could see it. I placed the SW edge of the Telrad just outside the star and was in position. After a bit of looking, and again pumping up the magnification with a 12 Nagler, I could detect 5 galaxies. NGCs 7549 (3'x1' N/S) and 7550 (round at 2'), at mags 13.8 and 13.6 respectively were easy, jumping out 4' apart and nailing down the location. A mag 10.7 star is within one minute of 7549. Soon, NGC 7547 at mag 14.7 popped in, 3' W of NGC 7550. NGC 7547 is elongated E/W, and is maybe 2' in length and 1' width. Next in view was NGC 7558, my initial target. This was very faint, and could not be held steady more than half the time. I do believe the mag 14.9, but not 16.0 for this object. Finally, the last of the group began to glow E of NGC 7549 by perhaps 5 arc-minutes. This was CGCG454-15, a mag 15.3 elliptical. The group turned out to be cross-catalogued as Hickson 93 and Arp 99. Steve Gottlieb looked at it, and e-mailed later that NGC 7558 (HCG 93e) had a much higher red shift than the other group members. As a point of interest, here are Steve's notes:

This is also HCG 93 and Arp 99. The redshifts are interesting: once again (like Stephan's Quintet, etc.) this group has a discordant member -- HCG 93e -- which has a much higher redshift than the other members. The radial velocities (heliocentric) in km/sec are:

Name v
(million l.y.)
HCG 93a 5140 260
HCG 93b 4672 235
HCG 93c 5132 255
HCG 93d 5173 260
HCG 93e 8881 445

Someone (Jamie?) asked about distances we are observing when tracking down some of these dim galaxies. There's an answer!

About 28 arc-minutes mostly east of NGC 7558 was another pair, which I finished the night on. NGCs 7578A and B are a double galaxy system. With the 12 Nagler I was able to begin breaking these apart. I'd like to try them with more power and more time. But by this time, the moon cresting the eastern hills, silhouetting a lone tree on the horizon from behind. It was a beautiful view, but signaled the end of the night's observing.

A few of us stood around, reminiscing about the great Loma Preita earthquake in 1989 that shook us all, comparing notes and talking about other earthquakes. Our observing site sits very close to California's notorious San Andreas fault. A few more bites of Jay Freeman's garlic and cheese pizza, and I was packing up to go home.

Then, for the final excitement of the night, a friend came over and said there was a car stuck in the drainage ditch that borders our setup area. The car was nosed in, with the chassis on both sides resting firmly on the ground. I had a huge laugh when told about the good soul (sorry about this, if you're the one, and are reading this) who tried helping the driver out. Standing on the opposite side of the ditch, he was looking at the left front tire from in front, and told the driver to try backing out. Well, the tires spun and launched dusty soil forward, engulfing the helper. As the dust settled, there he stood, slowly emerging from the clouds and patting himself down to clean off! This had to be one incredibly funny sight!

One person suggested not rolling the car out, since its frame was on the ground, saying isntead to call a tow-truck. The driver (who we shall all keep anonymous) shot back "sure.... how am I going to get a tow truck out here at this time of night".... I thought of calling AAA, but decided to watch for a bit more...

One of the observer pulled up his Jeep behind the stuck car, hooked on a tow-rope, and all was again well with the world.

It pays to observe in a group!

It was 1:47 a.m. and I was driving out of the park. Daylight savings time would end in 13 minutes. I arrived home almost an hour later, cleaned up and crawled into be at 1:46 a.m.

It was a great night. We had good skies, good friends and lots of laughs.

I'm looking forward to next weekend already.

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