Mt. Diablo, Saturday, 4/29/06

by Bill Cone

I set off about 7:00, not being sure quite how long it would take. In 25 minutes I was at the Park entrance. I paid my fee at the North gate and started the drive up. Is there any better way to start an evening of observing than by driving up a mountain in the late spring just before sunset? This is a beautiful drive, the road steep and curving, so you can't go fast. Best to enjoy the view. Sometimes the road curves and climbs in a manner that only the sky is visible at the end of the road.

Warm light was raking across the road, slamming into red earth embankments. and lichen splotched boulders. Red earth gets redder, shadows on grass go turquoise and the road turns violet . Up past the Juniper campground the road heads East, and the elevation afforded a beautiful view of the shadow of the mountain being cast deep, miles across the hills and valleys, finally absorbed into the great shadow of the night, gathering it's strength on the ground before rising up into the sky like a blue gray curtain with it's soft edge of pink diffracted light. Is this any different than Hubble's Variable nebula? Massive, moving shadows being cast into a mixture of dust and gases...

There is a huge parking lot below the summit on the western side of the mountain. Stunted pines, and radio/ communications towers with lights on them rise up on the North and South sides of the lot. In the NW corner of the lot sits a small observatory with a roll off roof, well protected by dense trees from wind. I estimated 20-40 people were up there, parked in 2 rows, working out of their tailgates.

Since I was a bit late, I didn't stroll around and gawk, but began setting up my gear, making sure I had everything, collimating, etc. It was not quite sunset at that elevation yet, though the world to the east was already in shadow, and the western horizon was yellow and orange. You could already see lights in the Danville/ San Ramon corridor. I started to look around, and introduced myself to my neighbor to the North, a nice guy from Sacramento named Don, with a c11 on a go to mount.

Just then someone pulled in to my South in a Subaru Outback. He opened the tailgate, pulled out ramps, and rolled out an 18" Obsession. His name was Jeff Justeson. Interesting neighbors! I was all set up, so took a stroll about, introducing myself to a few people. They were all very nice folks, welcoming me to the MDAS. I saw 3 more big scopes towards the observatory, 2 18" Obsessions, and something even larger. There was a refractor contingent starting at the North end of the second row of parked cars, giant binoculars on parallelogram mounts, and the ubiquitous SC scopes and Dobs of "modest" aperture. One guy was carrying around a little homemade 6" newtonian, like a lap dog, cradling it in his arms, and speaking about it with pride. There was a few guitar players over by the observatory. I could hear music from some other source... sun was going down. Some kind of a tribal geek festival going on here!

I had my 10" f 4.5 newtonian, a Starsplitter Compact model that is no longer made. Nova mirror.

It was intermittently windy for the first 45 minutes or so, but then it was dead calm, and relatively balmy for the rest of the night. Around 11 or so you could feel the humidity going up quite a bit, but no problem with dew on finders or optics.

My observing plan was to sketch Messier galaxies in Ursa Major, review (go back and find) stuff I've been looking at the last few months, and check out what's coming up in the summer sky. Of course I immediately amended this agenda to include mooching a few views out of Jeff's 18". I didn't count on all the goofy and fun distractions of a crowd, though.

I peeked at the moon in it's young phase and was blown away. The earthlight was magnificent...far more interesting than the narrow, glaring band of craters on the rim of the disc. I just had to draw that for awhile. Another project: Draw the new moon every month. Most of the full moon was revealed in the shadow, but in a soft illumination, so all the grey tones were revealed in an extraordinarily subtle dynamic range. Aristrarchus still stood out bright and harsh near the western limb. The big oceans were overlapping, grey circles. Plato popped out of the lighter colored alps like a button. I don't know the names of most of the features, but now I have a new project. The moon in Earthlight is easy on the eyes. Highly recommended if you want to see how dynamic and subtle a compressed grey scale can be.

m51: The circular glow around the core was bigger than I'd seen it before. Within that I could spot a few stars. The glow was not even, sometimes I detected a concentric pattern, other times a radial one. I could detect no apparent bridge to it's companion, and I mistrusted my desire to see spiral structure. It was definitely not a flat grey disc, but obvious spiral structure eluded me.

If you're trying to sketch without a tracking mount, you've got to keep working steadily. Otherwise, things have a habit of drifting away....

"Say, have you heard about this Carbon Star in Canes Venatici? I have a chart... They say it's diameter is THREE astronomical units!" I mulled that one over for awhile, as the Earth revolved m51 out of my fov. That IS a big star. And it's red. Maybe we should go look at it.

Y CVn: I checked Don's chart, then looked at it in SA 2000. Didn't seem hard to find, an easy hop North from the angle iron of Canes Venatici. And there it was in the finder scope. Looks like Mu Cephei, Herschel's "garnet" star in Cepheus. Topaz, not red. The reddest carbon star i've seen so far is one Gottlieb recommended last fall: S Cephei. Not bright, but DEEP red. Very satisfying. Still Y CVn had nice color.

I invited Jeff to come have a look at the Ghost of Jupiter, the blue planetary in Hydra. Of course he immediately wanted to see what it looked like in his 18"... Off we went! There it was: bigger and bluer than in my 10". Nice to see how color is intensified in the larger aperture. Much later that evening we looked at the Alberio double in his 18" and it was like looking at a kid's water color set. Extraordinary saturation in the blue and yellow.

We tried to see the Flaming Star Nebula, IC405, in Auriga, but it was a no-go, in either scope. With an O-III filter we could only detect a possible glow around one of the stars in the correct field. Auriga was getting pretty low in the West, so transparency and light pollution down there were probably the limiting factors.

Richard Ozer came around asking for a comet chart to find a guide star to get near it for ccd'ing it in the observatory scope. I introduced myself and we looked at a chart I had printed out that Rich posted last Saturday on TAC, then checked SA 2000 to pinpoint a useful star. Off he went. Nice guy. I had seen him earlier going around talking to folks, but didn't know who he was.

Ursa Major Messier sketching was going out the window. Comet fever had hit.

In looking at the B and C fragments that night it struck me how comets have the same visual properties as many of the galaxies at the eyepiece: The stellar core, and the surrounding oval glow. It's helps one to understand how early astronomers could confuse the 2, and draw all sorts of mistaken conclusions. If they are the same thing as comets, then why don't they move? Where are they in space relative to us? etc. Interesting when something relatively close and small, and something incomprehensibly distant and vast, have almost identical visual cues. This phenomenon can lead to centuries of scientific confusion...

SW-3: The C fragment had moved about 4 degrees E. since I'd last seen it at Briones on the 27th. Crossing the border into Hercules, it was now about a degree W. off of the SW corner of the Keystone. More galaxies should look like these comet fragments! Big, bright core, large surrounding glow. Radiant objects.

I studied the chart and decided to go for the B fragment. It didn't take long. Both these fragments were easy targets in binoculars and the finderscopes. B fragment did not seem to have as bright a core, but was equally big and bright overall.

We kept going back throughout the evening to check on them, comparing them through our scopes. Objects this bright didn't seem that dynamically different between the 10 and the 18 to my eyes, at similar magnification.

IC 4617: I was looking at the B fragment through Jeff's 18" when a couple came by and engaged him in conversation. While he was thus occupied, I took that opportunity to swing his scope over for a stealth peek at M-13. Looking good! I moved it partialy out of the field and started to look for ngc 6207, the nearby galaxy.... Yea, there it is! The funny thing was it looked a lot fainter than I'd seen it the other night at Briones in my 10". Hmmmm.... who cares. I announced that I had m13 and 6207, and Jeff came over to look.

He said the field was too small to see it, and swapped out eyepieces, as aperture starved observers flocked around his scope like vultures on carrion... I didn't look again, but I was sure I saw a galaxy there. On Sunday I looked at some charts and saw that there IS a galaxy between 6297 and m13: IC 4617. TAC folks have observed it.

Freeman has a hilarious OR on it:

/reports/97.05.09.4.html

I even found an OR on google for it in a 10", so I'm going looking for that one next time out. Who knows.

I suggested to Don, my C11 neighbor, that he take a look at ngc 2419, the intergalactic wanderer, if only for the conceptual thrill of seeing something, on the edge of our galaxy. He punched in the coordinates, slewed his scope over and didn't see it. I took a look.

Yep, it was there all right: dim, tiny patch beyond the bent 3 star asterism.

I described it and told him where to look and he could finally see it. I remember having that experience many times when I didn't know "what" to look for at the eyepiece. You see a photo of something, and it is very, very easy to get suckered into believing you will see it with such clarity.

Jupiter was up and Jeff was offering views in the 18": Never seen anything like it before: more belts, detail in the belts, swirling edges. subtle color and textures in the belts, Io coming off of the limb of the planet....

Saturn's got the "logo in outer space" award for amazing form, but Jupiter is hands down the winner on surface color and textural detail. I was floored. Seemed to look like that photo that was posted on TAC last week, but without the shadow transit dot. I felt I was seeing everything I could see in the photo. Unreal. Big aperture and good seeing delivers big time.

Back to galaxy sketching. I worked my way through M63, M94, and M106, taking my time on the drawings. I struggled for awhile to find M-106. It was near zenith, and I just wasn't reading my charts well to starhop to it. Finally got it.

Jeff had ngc 4565 in the 18". Marek had rhapsodized about it at Coe a few months back in an OR, and I had since seen it at MB in my 10". I was suitably impressed at the view in the 18". The galaxy is a spindle with a large central halo/ core, and a prominent dust lane running through it, slightly below center. The center glow below the dust lane is a subtle hint.

Summer sky was rising. We started poking around at globs m3, m4, m53, m5...

I looked around the lot, and most folks had cleared out. There were still two 18" scopes closer to the observatory, with a happy bunch hanging around. We wandered over there. Both scopes had Jupiter, one stopped down with a 2 hole aperture mask, and the other, full aperture, on a tracking mount. Full aperture beat the stopped down view for detail, to my eyes. Again I was blown away. The GRS had rotated into view and was just E. of the Meridian, if I'm orienting myself right.

Can we call it the Great Sashimi? It's salmon colored! And it appeared to be leaking, as there was a big pale stain of the same color coming off it on the northern side, running west. Dark, arcing swirls coming off of the edge of the NEB into the white central zone like a bunch of standing waves. I started wondering if they were actually gaps....shadows in the clouds, not dark material. Anyone know this?

We took turns swapping views in both scopes for a good 20 minutes discussing the views and kidding around. It was close to 2 am. Cassiopeia was standing level, bisected perfectly by one of the towers at the North end of the lot.... just like the 'big W' in it's a Mad, mad, mad world.

What a night. So this is what you've all been going on about.

Posted on sf-bay-tac May 03, 2006 13:08:30 PT
Converted by report.pm 1.4 May 04, 2006 21:48:21 PT