FP 12/10-11/2004: What's a little cirrus on such a nice

by Marek Cichanski


Friday night, 12 / 10-11 / 2004, was a very nice night at Fremont Peak. True, there was a significant amount of high cirrus drifting by all night, and it cut into the observing fairly significantly, but it didn't make David Kingsley and I feel any less glad to have made the trip. Aside from the cirrus and some intermittent wind, conditions were very nice, we saw some great views through our scopes, and the evening and dawn which bookended the night were lovely.

I left home around 2:30 pm on Friday, heading for the Peak Pads. Had a little traffic to cope with in San Jose, but nothing too bad. As I got up towards the top of the Peak, I could see that I was getting above most of the haze and crud that I'd been in while driving through the Santa Clara valley. The sky was almost completely clear at sunset, but high, patchy cirrus soon drifted by, a theme that would go on all night. John Gleason arrived and set up for some wide-field H-alpha imaging at the saddle. David Kingsley arrived at the Pads not long after dark, and the three of us had the place to ourselves.

Except for the intermittent high scud, conditions were generally very pleasant. I rigged up my dew heaters, but soon took them off, and never needed to put them back on. It stayed perfectly dry all night, not a drop of dew. Paper stayed nice and crisp, even after sitting out all night. Wind came and went, sometimes getting downright annoying, but it was usually possible to look at wide-field views until it abated. Seeing was probably about 3-4 out of 5 for most of the night, and the limiting magnitude (behind the cirrus) was probably a solid 6 by my estimate. Haze and fog moved into the valleys and darkened up the light domes somewhat. If there hadn't been high clouds reflecting the remaining light pollution our way, it would have been a really prime night.

Although I've already had my first light with the "M" Obsession, this was my 'first dark' with it. It was really nice to get it out under a dark sky. I didn't have any particular plan, aside from using the Night Sky Observer's Guide. I've had NSOG for a couple of years now, but I've never really used it. Last night I found out what I'd been missing. As the clouds and holes drifted by, I'd choose a 'constellation of opportunity', open up NSOG, and bag a couple of objects. Almost everything that I looked at was interesting and worth going after. Finally having some aperture helps, too, of course, because few objects in these books require a scope beyond 18".

I didn't bag a whole lot of objects, thanks to the clouds, but here are the ones I did manage to hunt down. I mostly used NSOG's little bitty finder charts, but had to resort to Uranometria on a couple of occasions:

Scope18" f/4.5 Obsession dob with TeleVue Visual ParaCorr.
NGC 185 (Gx, Cas)22 Nagler, 1/4 field size, pretty bright, pretty much extended north-south. Concentrated nucleus, but not stellar. Nice!
NGC 147 (Gx, Cas)22 Nagler, similar size and position angle to NGC 185. As noted in NSOG, it's fainter than NGC 185, but still plenty doable. Looks a bit more elongated than 185, and it's pretty faint to considerably faint. Looks like it has a prominent stellar core, but that could just be a dim superimposed field star.
NGC 278 (Gx, Cas)22 Nagler, small field size, considerably bright to bright, round. Has a nucleus that is concentrated but not quite stellar. Hints of mottling or structure in the halo. A bright field star lies to the NW, which is part of a half-circle of prominent field stars to the N of the galaxy. A slightly dimmer, but still prominent field star lies to the south.
M33 (Gx, Tri)31 Nagler, looks remarkable from up here at Fremont Peak. Lots of bright knots are visible, and I get the impression that I'm seeing two distinct spiral arms. They give the galaxy a lazy backwards-S shape. The nebula in M33 is very prominent. A noticeably better view than from Montebello.
NGC 1084 (Gx, Eri)17 Nagler, small field size, pretty bright, stands out prominently. Pretty much extended NE-SW. The north end of the galaxy appears to be a bit more sharply defined than the south end. Gradually brighter towards the center, with just a bit of a semi-stellar nucleus.
NGC 1514 (pn, Tau)22 Nagler. I missed seeing this in the eyepiece until I realized how big it is! Surrounds a prominent central star. Small field size, pretty bright (with OIII filter), shows mottled / concentric-light-and-dark structure. Let's try the 9 Nagler... it responds well to magnification. 263x enabled me to see the uneven, mottled, dumbbell-like shape noted in NSOG. (David told me to try higher magnifications to bring out more detail, and he's absolutely right. I think that I've traditionally shied away from magnification, but this aperture really allows mag to bright out the detail.)
IC 443 (bn, Gem)22 Nagler with OIII filter, central field size, faint, elongated east-west and arcuate in shape. Convex towards the NW. A faint patch of nebulosity involved with several stars in a rich field. This nebula required averted vision, an OIII filter, and scope jiggling in order to spot, but it was noticeable once found. The edges of the nebula are indistinct, and the overall shape is hard to apprehend, other than being elongated and arcuate. It's nice to bag an IC! This NSOG business is working out great!
ICC 444 (ref neb, Gem)12 Nagler, small field size, bright, considerably extended east-west. I think I can convince myself that there's an east-west patch of nebulosity surrounding the star 12 Geminorum, and not just eyepiece flare. The purported nebula appears to have a sharply defined edge on its north side, but not its south side.
Collinder 89DNF. Huh? I just don't see a cluster in the area indicated by NSOG, even at lowest power (76x with the 31 Nagler).
Rosette NebulaDavid showed me the Rosette through his scope, and then I looked at it through mine. With the 31 Nagler and an Orion Ultrablock filter, it was beautiful. This eypeiece framed the nebula quite nicely in David's scope, but it just barely fit in the field in my scope. A remarkable amount of detail was visible. Lots of complex, billowing nebulosity. One could stare for hours at it. Not tremendously bright like M42, but a complex, subtle beauty.
Orion NebulaI spent an inordinate amount of time gazing slack-jawed at M42. Seeing it for the first time in a big scope like this, under a dark sky, it was captivating. Again I followed David's advice, and increased the magnification to 263x (9 Nagler), and it really did bring out detail. The E and F stars in the Trapezium were prominent (even back at 107x), and the greenish-blue color of the area around the Trapezium was distinct. A bit of ruddy color was visible farther out. John(?) Herschel's description of the inner part of M42 as looking like 'the breaking up of a mackerel sky' seemed quite apt. David pointed out that M42 'got William Herschel thinking more seriously about astronomy', and I can see why! This triggered a long discussion between David and myself, sharing our stories of visiting the William Herschel Museum in Bath, England. W.H. was the man.
M81 and M82Crazy! Very bright and spectacular. I could just fit them both in the field of the 31 Nagler. With the 9 Nagler, the detail in the Cigar Galaxy was awesome. Bright knots galore, and the transverse dust lane nearly cuts the galaxy in half.

Around midnight Saturn was perfectly placed for 'flat footed, standup' viewing in the M scope. Seeing at this point was probably a consistent 3.5 on my scale of 5, with frequent moments of 4 to 4.5. The planet was knock-your-socks-off bright and detailed. Sharp details in the rings, with the Cassini division and the Crepe Ring standing out beautifully. I had sketched a chart of the moons from Starry Night Pro before leaving home, and David and I were able to bag all of the visible moons except Mimas. Dione, Tethys, Rhea, Titan, and Iapetus were all easy-peasy. Enceladus required averted vision. No joy on Mimas, though, through either of our scopes.

At one point, David put a 9 Nagler + ParaCorr + 5x Powermate in his 14.5" Starmaster, which has alt-az tracking. He estimated that it was about 1000x. We had a good laugh about the ridiculous magnification, but here's the real funny part - it held up! The mirror must be great, the collimation must have been great, and the seeing had gotten pretty darn good. The view really was seeing-limited, not optics-limited. Having Saturn look that big in the eyepiece, and still be reasonably bright, while showing detail, was awesome. Aperture, quality optics, and precise collimation win. It rather reduced my lust for something like a 6" apochromatic refractor - but rather increased my lust for tracking on my own dob...

At 1 am the vibrating alarm on my Casio moon-phase watch went off, and David and I walked up the hill to look for Canopus. We were confident that we saw it, although it was quite dim and orange from atmospheric extinction and refraction. We used Karkoschka's atlas to confirm the I.D. It was really neat to see Canopus from home, even if it was just a little orange speck hanging above the dim and distant ridgeline of the Sierra de Salinas. It took me back to those summer nights in New Zealand, with Sirius, Canopus, and Achernar riding overhead.

Most of the rest of the night was devoted to 'Messiers of Opportunity'. I looked at whatever was visible between or through the clouds. Looked at the open clusters in Auriga numerous times, as well as the Double Cluster, M35, M46, M47, M41, and M79. Magged up on the planetary in M46 and slapped in an OIII filter. Nice. As the wee hours wore on, I was amazed to see so many spring constellations - Leo, Hydra, Corvus, and even Coma B and Virgo! I saw M95 / M96 / M105 through some scud, but they weren't very spectacular. I even looked at M51, also through thin cirrus. It still looked nice, with some sprial structure visible in M51, and the satellite galaxy standing out nicely, but no bridge. Woulda liked to have seen that bridge. I also looked at a group of NGC galaxies somewhere, maybe in Eridanus. (I wanted to have an eyepiece field full of galaxies.) Also took a gander at Comet Machholz. More of an ED80 object, it's so big. I tried for NGC 4565 in Coma B, but the clouds put paid to that idea.

David and I sacked out in our respective vehicles from about 3am to 6am. I hadn't thought to bring a sleeping bag or pad, but it was so mild (low 60s) that I just put some clothes down in the back of my Jeep, pulled a down parka over the upper half of my body, and sacked out. Woke up to a gorgeous predawn. Sharply cut eastern skyline in front a brilliant yellow. Clean transparent air above low-lying haze and fog. Still some scud in the sky, though, which was kind of good, because it meant that we hadn't missed a big clearing. Our scopes were still set up, so we looked at Jupiter. In David's scope, with tracking, it was very sharp and detailed. A moon had just come out from behind the planet, and it appeared that the Great Pale Spot was visible. I took a quick peek at Venus, it was nearly full. I packed up in jeans and a t-shirt, having no need for the usual winter garb. It was a beautiful drive down the mountain. Arrived home 18 hours after I left. All in all, a very worthwhile night. David and I felt that we'd gotten some good value out of this dark moon cycle.


Posted on sf-bay-tac Dec 11, 2004 10:59:13 PT
Converted by report.pm 1.2 Jan 22, 2005 19:01:20 PT