Peak, 5/10-11/2007: Coma-B, Cor-Bor, and Beyond

by Marek Cichanski

I say that because yesterday afternoon the cirrus clouds were bumming me out in a big way. I had reserved myself a night on the Challenger, and I'd been looking forward to it like... I wish I could think of a colorful and humorous simile right now. At any rate, I'd been psyched all week. But, as yesterday afternoon wore on, some cirrus clouds formed up in that SW flow that we're under, and they started to stream across much of the Bay Area.

But, since I didn't have a lot to load up, I jumped in the Jeep and headed for the Peak as soon as work was done. There's nothing quite as relaxing for me as a nice weeknight at the Peak, with the mountain all to myself.

Sunset and twilight brought some hope, as I opened up the observatory and got things ready. It was clear that I at least had a lot of large holes to shoot through, and I was using an equatorially mounted telescope with 'push-to' encoders.

The marine layer was nicely positioned. The top of it probably wasn't significantly higher than 2000 feet, if that. I could look over the top of the fog during twilight with my binoculars and see trees poking up through the sharply-defined top of the fog layer. There was still some haze up at Peak level (2750'), which was annoying, but it wasn't a dealbreaker. Around astronomical twilight, the wind died, it got a little warmer, the cirrus clouds cleared, and it stayed really pleasant all night. What a tremendous piece of luck! Seeing was average, nothing spectacular, but plenty usable. Sky was pretty dark due to the marine layer, but not quite a full-on Black Cloud Night with no evidence of the Bay Area or anything. Still, the effect of the marine layer was noticeable. Never had any problem with dew all night long, though.

During twilight I started with Saturn, and had a decent, serviceable view of the Cassini Division, some bands, and some moons. To wit: Rhea, Tethys, Titan, Enceladus, and Dione. Some kind soul had recently installed Starry Night Pro on the observatory computer, which did a much better job of representing the positions of the moons than TheSky.

Once it was dark, and I was marveling at the clear sky, I decided to take advantage of it while it lasted, and I went right for the Coma Berenices galaxy cluster. I must have observed some of the members of this cluster before, but I'd have to search my old logbooks, as I don't have any specific memories of it. I would assume that some of the members are on the H400 list, and so presumably I've looked at it, but I couldn't recall looking at it for the specific purpose of 'looking at a galaxy cluster'. I knew that there was a 'Coma-B gx cluster', separate from the Virgo Cluster, but I guess I'd never made a point of looking at it.

What a revelation! Run, don't walk, to look at this thing, if you haven't already. Of course, I was using a great big scope, but any large scope will probably show a fair number of the members. Something like a 15" or an 18" would probably show a lot of what I saw, judging from how bright the members looked in the 30". My preparation was actually rather minimal, I just printed a DSS image and a chart from the Wikipedia page on 'Coma Cluster'.

I didn't make any detailed log entries about the members - my taste for that is pretty minimal anymore - but I had a ton of fun checking off the galaxies on the chart once I confirmed them. What a hoot! Even at the focal length of the 30", the FOV of the 31mm Nagler easily held 30 or 40 galaxies. (136x, 0.6 degrees, with ParaCorr) A little AV was all that was needed to pick up the fainter NGC and IC members. I think I bagged 45 members. Fun!

Somehow I'd missed out on the Coma Gx Cluster all these years, but it's just a wonderful playground. I always assumed that the concept of Springtime Galaxies just meant Virgo, but I didn't realize what a wonderful jewel box is waiting in Coma B. Honestly, it was like looking at some sort of Hubble Deep Field. Here's how I described it in my notebook: "It's sort of a 'galactic' version of the 'Magellanic' experience. It's that feeling of 'standing off at a moderate distance and being able to take the whole thing in, but able to see detail, too'. This is really a remarkable sight."

Playskool oughta market a Nerf version of this thing as My First Galaxy Cluster. Simply marvelous.

Then, it was on to even bigger quarry... the Corona Borealis galaxy cluster. Now, this thing was my nemesis. It's on Steve Gottlieb's challenge list, and I'd tried to see it from Shingletown in my 18", and I'd gotten spanked. I'd even tried it in the 30" once before, but no joy. So, this thing was my Red Baron. It's clear that it's a challenging galaxy cluster, being 5 times farther away than the Coma Gx Cluster. (1.5 billion l.y., as opposed to ca. 300 million l.y., IIRC) Steve's report clearly shows that it's no giveaway, not by a long shot:

http://astronomy-mall.com/Adventures.In.Deep.Space/agc2065.htm

Last night I discovered two key factors for seeing clusters like Cor-Bor:

1) Mag Up.

Many people have been slowly breaking down my resistance to high magnification over the years - David Kingsley, Albert Highe, Steve Gottlieb, Jamie Dillon, to name the principals. And I've slowly come to realize that seeing members of galaxy clusters ain't like looking at Messiers. I knew from the outset that if I could get on the right field, it was going to be Mag Up Time.

2) It's Better To Be Lucky Than Good.

I had printed a DSS chart of the cluster, and I'd examined the annotated image in Steve's article. It seemed like the key was to find the "Ares-shaped" arc of three stars that lie in front of the cluster. So, I sync-ed the encoders to some nearby object, swung on to the position, and gave the field a quick look-see with something like a 17mm Nagler. Clearly not enough mag to work on the cluster members, but maybe I'd get some idea of where I was. I was expecting a long struggle.

First look, and I found myself saying 'hey, could THAT thing the the "Ares"?' And then, a second later... smudges! Right where they oughta be! I could hardly believe my luck, so I checked some other stars against the field shown in my DSS image and on The Sky, and sure enough, it looked like I was in the right place. And the smudges weren't going away!

So, I magged up, and sure enough, there they were. Everything I saw in the cluster was basically an averted-vision object, and most of them were challenging AV objects. Some could only be seen 15 or 25 or 50 percent of the time. But I was able to make a surprising number of repeatable identifications. I went back and forth between the DSS image and the eyepiece, even taking a break to go outside the observatory and have a snack at one point. (The tracking on the Challenger is so money that one can actually afford to do this. The crew back in '86 NAILED that polar alignment.)

In the end, although I hesitate to say it, I had identified over 15 members of the cluster. If I'm really right about that, I think it's a big-time object lesson in that most basic tenet of observing, so eloquently stated by Jay Freeman years ago: "Aperture Wins, and wins big".

At this point, it wasn't even midnight yet. What OTHER crazy stuff should I go after, I wondered? One though immediately occurred to me: If you've just knocked off your biggest SGNB nemesis, why not try something that used to be on the AINTNO list?

Two words: M87's Jet.

Well, at least the 'host' object is easy to find!

And, with help from Burnham's description and photo, I feel that I had intermittent, but repeatable, glimpses of it. Being reminded of its P.A. and 'knotty' nature was a big help. Perhaps enough to make the skeptical reader doubt the identification, and that's a perfectly reasonable doubt. But I think that it was there at ca. 450x-600x (9mm and 7mm Naglers). Is that the Fastest Physical Object I've ever seen? That'd be interesting to find out. Especially if we don't count the expansion of the universe.

Well, feeling full of oats, it was time to try the Double Quasar. I had a leftover finder chart for it that I'd printed some while back. I think I'd wanted to try it at Shingletown, but it was too low. The beauty of this object is that the galaxy NGC 3079 points the way, which is a major help. And sure enough... with the 9mm and 7mm Naglers, I was able to split it. Cool! It was an intermittent split, and it was AV all the way, but I saw it as two distinct objects with the right PA on several occasions. I used the charts from this webpage:

http://www.skyhound.com/sh/archive/mar/Q0957+0561A.html

Neat! That page quotes a '9 billion light year' distance, which I know is a hard thing to specify at those sorts of redshifts, but still. It's always cool to see something that far away. And to see gravitational lensing, too.

At this point it was 1 am, and I was starting to feel the need for the night's first eye candy. So, since I was in UMA, I went to M81. My notebook reads "OMG! As the eye 'integrates', a faint, ghostly, but 'definitely-there' oval ring appears around the 'galaxy'. It looks like I'm seeing the outer spiral arm structure! What a sight. There's even an 'NGC-206-type' concentration to the S of the nucleus.' This view of M81 was the first of several 'photographic' views that I had last night. These were views that showed structure to an extent that I normally only recall seeing in photographs.

And if I thought that was impressive, just wait until I pushed over to M82! The knotty detail was insane.

NGC 4565 was, of course, stunning in the binoviewer with 24mm Panoptics. Pretty much filled the width of the FOV. The nucleus looked utterly stellar, and there was a clear sense of the dust lane being in front of the nucleus.

Then, my best view ever of M64. Very nice delineation of the 'black eye', and there was a bright rim visible around the 'black eye', with this rim being brighter on the side away from the nucleus. Faint hints of additional spiral structure were also seen.

I listened to Gendler's essay on M51 while looking at the genuine article. I won't even try to use something as feeble as words to describe the spiral arm detail in M51, and the bridge to NGC 5195, and the dust knot in 5195. My notebook says "With the right AV, the image of M51 'integrates' to give a tantalizing hint of the detail seen on images. Another 'photgraphic' view. Wonderful!"

And so the night wrapped up with more eye candy. M3 (The Poor Man's Omega Cen), M5 (The Poor Man's 47 Tuc), and M8 with an OIII filter. Dark tendrils and globules for days. I could spend an entire summer night staring at that thing. I finished the night with a binoviewer session on Jupiter. It was a little soft, but it had its moments of nice detail. Caught the end of a shadow transit and the GRS.

Wow, what a wonderful night. The dissipation of the cirrus was an inestimable gift, which granted me another great Fortress of Solitude night of the sort that I treasure so much. I closed up the observatory at 4, caught a few winks on one of the pads, and joined the commute back north in the morning.

It never got dewy, but during the last hour or so it got a little more cool and humid. The fog was still well below the Peak, and still had a sharp top, but it seemed like a bit more cool moist air was making it up to Peak level. As I drove down at 7 am, the top of the fog was right at the top of the quarried hill - this puts it at 1900 feet.

Now I'm really tired, and I'm going to sack out. Looking forward to going back to the Peak with my 18" on Saturday if the weather's good. Jamie, I'll see ya there.

Marek