Monday, December 7, 2015

OR, Henry Coe SP, 10/27/2014

Seeing good sky conditions forecasted and having otherwise missed other new moon observing opportunities due to weather, I found ways to accommodate work and family commitments and headed up to Henry Coe SP overflow lot for a Monday night session. There were some high clouds in the afternoon, but these blew to the south/south east after sunset and the sky was clear the rest of the night. I was the only one there; only one car drove by the entire night. This is the third occasion I’ve had the lot to myself, and I’ve only started observing since March this year!

Because the nightfall temperature drops so quickly this time of year, I attempted to get a head start on optics cool down by running a fan at the back of my mirror during the drive down, with the air conditioning set on high. I’ve a 2” thick Pyrex 12.5” f/7 mirror, so it does take a while. It was colder than my air conditioning when I arrived at sunset, so I kept the fan running. I star tested occasionally through the night and noticed the wormy patterns in the image, indicating hot spots, so I left the fan running off a battery until 11:30 before I could remove the fan.

Best Visual Limiting Magnitude I had in the night (from surveying stars within Eridanus around 1am) was 6.0. Transparency was excellent all night, while seeing peaked at excellent from 11pm-2am, then fell to just above average afterward. San Jose and Gilroy were bright all night; no matter, I made all my observations to the east. I rechecked collimation after every couple of hours to keep everything in tune. While it was cold, there was a steady breeze so dew never formed – not a drop. That’s the nice thing about hilltop sites: dew is usually less of a factor.

As for the wildlife: I’ve gotten used to rustlings in the grass and bushes around the parking area, but I was startled at 9:30pm by a the sound of a pack of coyotes who were very close, I’m guessing the hilltop to the north of the lot, who started yelping and howling to another group who answered from a more distant hill. I started yelling and slamming my aluminum ladder on the ground to make a ruckus—just to make myself feel better. No screaming mountain lions this night, to my relief. All was quiet and calm after midnight, so I was calm too. I observed until 3am when I felt “done,” then slept in my minivan. I woke when it was still dark and saw a bright object high in the west; realizing it was Jupiter, I got back out and observed it for half an hour, then went back to sleep until dawn.

I continued my traverse through the H400 list and bagged a few Messiers along the way. I also made a try for several faint nebulas and challenge objects. Here are a few highlights, in no particular order:

NGC 253, Gx, Scl, 0047 -2818, 100x: Bright, visible with direct vision; averted helped draw out the surprisingly long halo, which faded out gradually to both ends of the 0.8* TFOV. No definite structure, however it appeared brighter & slightly mottled on the south western end of the halo. I saw three stars which were in front of the galaxy.

NGC 1023, Gx, Per, 0240 3903, 100x: Lovely, bright and elongated E-W. Stellar core & halo with DV, AV yielding greater proportions. Two faint stars on each end. Near the South Galactic Pole!

NGC 1444, OC, Per, 0349 5240, 170x: Struve 446 (pretty, A yellowish B blue/brown) with a line of 5 stars to north. There are 5 more slightly brighter stars boxing the scene, which better be part of this cluster or this is a sorry excuse for an object, William! [Direct quote from my notes…]

NGC 1499, California Nebula, 0403 3622, 63x, 5mm exit pupil, H-Beta filter: A thin milky wash, noticeable when scanning the edges along its huge length to contrast with the dark surrounding sky. Relatively brighter in the central portion with some drawn-out wisps in this area; otherwise it was a grayish smudge on the tips.

IC 434, Horsehead Nebula, 63x, 5mm exit pupil, H-Beta filter: Keeping the bright Orion belt star just out of the FOV, I could distinguish a dark thumb shaped intrusion into the brighter nebulosity running between two stars. It took me a long while of staring and study before I convinced myself I could see it (and I still feel a little tentative about it).

Fornax Dwarf Galaxy: I saw this on the chart and decided to find it on a whim, not knowing any information about it in advance. It was very low, and I ended up in the area after a long star hop from Upsilon Ceti. Since it was charted as a large object I used 41mm Panoptic, 5.9 exit pupil, 54x 1.3* TFOV. I’d appreciate if other observers could instruct me whether what I perceived was really the galaxy: I observed an extremely faint graying of the sky, boxed by 4 stars (all of which were on my chart, the SW one being Lambda 2). There was no defined edge but a gradual change in the grayscale to black where the edge of the galaxy, as noted on the chart, should be. I did not observe any globular clusters which as I read about this object today notice are the commonly observed feature. Is it possible the graying is the galaxy?

Jupiter: Tried a range of magnifications but 277x was best when seeing stilled. Banding up through temporal zone, bluish festoons, and a diminutive red spot near the limb. Nice color in the polar regions, a little tan to brown – but not shadowed.

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