by Jeff Crilly
Earlier, in discussions about the evening, Marek The Optimist beseeched...
We got a pretty thick marine layer in my part of Palo Alto last night. I don't know where the top of it was, but if we're lucky, and if it's below MB, things could get fairly dark. Let's keep our fingers crossed!
A certain David Kingsley analysed NWS discussion along with observing site altitudes....
A marine layer at "about 2500 feet" is right at the level that will either take out or make a great night at our typical Bay Area locations. When I collected data to send to Atilla Danko for setting up the Clear Sky clocks at local observing sites back in 2001, the elevation data I had at the time was:
Montebello: 2284 feet Coe: 2600 feet Fremont Peak: 2800 feet.
From those numbers, I would guess that tonight would be a great night at the Peak, an iffy one at Coe, and a wet one at Montebello if the marine layer really is at 2500 feet. But with numbers so close, the only way to tell is to try. Good luck to anyone heading out tonight!
And what a night it turned out to be. Apparantly, Good Luck was with us.
I arrived well before sunset to a totally clear sky with only a hint of fog further along the ridge, north of MB. Pete S was already there (whom I hadnt seen in ~ages~). Soon thereafter more cars rolled in, and more scopes were setup... As the number of scopes increased, the fog in the south crept up closer and closer to the parking lot... Coincidence? I think not!
I counted about 14 scopes.. just an estimate.
With darkness came wetness... dew was getting everywhere; fortunately James came prepared with enough hot air for everyone -- from his 12v dryer.
We turned to the crescent moon.. a lovely sight with jupiter just off to the south... James had expressed an earlier desire to see what the moon was like with the C102F. We started with a barlowed plossl -- yielding about 245x. And what a view of the moon it was... we motored around a bit, then he went to fetch the 3-6mm zoom. We plunked that in with the 3x barlow for 900x. Hmm.. we could still see craters.. and it was *tack sharp*. Ok.. maybe just a wee bit fuzzy. So we backed off the zoom a bit to 450x. (Seeing was indeed a bit soft; this was a view not for those susceptible to ocean sickness.)
(Btw, Jupiter at 900x was a bit too fuzzy... Musta been some storms on that gas giant. B^)
I also enjoyed a few bright deepsky fuzzies through mark's scope... in the virgo area -- 4216 I beleive (though we couldnt see the companions in the 10inch).
Later, we wandered over to Pete, and did see the triplet -- he had just imaged it.
As the night went on, the wetness turned to dryness. And the creeping fog receded as folks started to packup and depart. (Coincidence?) A slight warm breeze from the south had come up, nothing annoying.
With the moon down, I moved on to the project of the night -- to finish up a test roll of Provia 400F on objects in the south... M4 and the Lagoon.
In between these exposures, the last of the obsserves departed, and I remained with quite good skies, for that last long exposure.
So there I sat, sipping an espresso, and touring the familiar messiers in the south with the 15x50s: the Swan, Lagoon, m80, m22, and the other globulars in the south. Cygnus was now high overhead. A sky test I like to perfom is to try for the veil in binos... I hadnt done this with the 15x50s.. and on this night there was only a hint of 6992 (http://www.ne.jp/asahi/stellar/scenes/object_e/veil.htm)
It was getting late... very late... I wanted to stay longer, but didnt fancy another drive home in rush hour traffic.
As I headed down the winding road, I encountered the fog. It was just as Marek had hoped; the Fog had come in, blanketing the lights of the valley. And it was sitting just below MB. Though there was still a light dome to the east and north, this was the most attenuated I had seen it in a long time.
It was indeed one of the more memorable Montebello nights.
Thank you Open Space Preserve people.