Observing Report: San Antonio Valley, 8-Aug-2001

by Steve Sergeant

Observing Report: San Antonio Valley, 8-Aug-2001

I made arrangements to meet Bruce Jensen on Saturday, September 8, at a private-property site in the San Antonio Valley. This site is described in the TAC sites list </sites/sav.html>.

I left my northern San Jose home about 17:45, and drove the scenic route over Mount Hamilton. As I passed by the observatory, I noted that several cars were arriving for one of the public nights.

Winding through the hills and valleys between Mount Hamilton and the San Antonio Valley, I encountered a flock of peacocks in the road at one point. I had to wait a couple of minutes for them to clear the road enough that I could drive by. At another point I saw a couple of elk on the far side of a barbed wire fence, looking like they wanted to get over it onto the road.

I made it into the area of the San Antonio Valley about 19:40. The directions on the TAC site assume that you're coming from the Livermore direction. From the intersection of Alum Rock Avenue and Mount Hamilton Road the driving distance is 37.3 miles, and the gate is the first big one with a broad driveway apron on the right after the first 4-way intersection sign one encounters beyond the top of Mount Hamilton.

I followed the directions: "...the gate will be unlocked by sunset or before; simply slide the gate latch open, proceed through (closing the gate behind) and drive east on the gravel road about 0.5 mile until you are through the cattle guard. This is the normal observing site."

The main gate at the road was unlocked all right, so I proceeded exactly 0.5 miles down a gravel road, past a LOT of cows and at least one bull, to a cattle guard. There was a locked red metal gate at the cattle guard -- I could neither get through it to the other side, nor see anybody set up beyond it.

Not being complete certain that I was at the right place, and not wanting to hang around on unfamiliar private property where I might not be welcome (especially by the bull), I went back outside the unlocked gate to the roadside, and waited for astronomical twilight.

One local drove out through the gate, and I asked him about a stargazing location. He didn't know anything about anybody who opens up their property for astronomers. "It's all just private ranch land out here."

At first, I thought my sunset time data was off: The sky was so-oo dark and clear and steady at zenith, but the stubborn bright glow remained on the northwestern horizon. By 21:00 I decided that I hadn't completely escaped the Bay Area light dome, and focused on the areas of the sky that were really dark.

I got out my 8X42 binoculars and started hunting for teapot DSOs: M7, M6 M8, M23, M25, M17, M16, & M4, and jumped out at me very easily. The M31 core was clearly visible naked-eye. I opened up my chart to see what else I could see with modest aperture and magnification. M2 & M15 weren't difficult to pick out, and in spite of some Livermore skyglow, I'm certain I detected M81 & M82. M27 was reasonably easy, and I'm also confident that I detected M57. Another good binocular object I sighted was the double cluster, NGC-869 and NGC-884, in Perseus.

I would rate the darker directions to zenith, the East, and South of this site as a bit above 3 on the Bortle scale, and the brighter directions to the North and Northwest at a bit below 4. Let's call it between 3.2 and 3.8.

The noises of numerous animals, some easily identified, some very difficult to identify, filled the night. Some distant lights from ranch homes were not really a hindrance to night vision, but were noticeable. I heard, and sometimes felt, the occasional swoosh of a bat overhead.

I decided that I wasn't going to set up my 'scope alone, in a place I wasn't sure I was welcome, so about 21:45 I set out for home. About a mile down the road, in another wide driveway apron on the west side, I saw a man with a very large Dobsonian scope set up. I stopped to talk to him and eventually wound up looking through the scope with him for most of an hour.

Kevin Mitchel was at the helm of his 17.5" Coulter Odyssey. He said he also drove over the Mount Hamilton Road from San Jose. He was looking at M51 when I arrived, and in spite of the skyglow in that direction, I clearly saw the spiral structure in NGC-5194, and could see at least some of the connecting dust lane to NGC-5195.

We proceeded to look at M8 next. He explained that the nebulosity in the cluster (as opposed to the nebula itself) was brighter here than anywhere else he could drive in 90 minutes from San Jose. It certainly was a near-photographic view.

To show off his scope and the dark sky there, he brought up the Veil Nebula, NGC-6960. This object was quite clearly visible without a filter, and full of the folds and waves that give it its name. I certainly can't remember a better view of this object. Impressed with the detail and contrast, I studied it for a while.

Kevin had a 1-1/4" focuser on this scope. I asked him about the eyepiece. It was a Celestron 25mm wide-field that they developed and never marketed.

We snagged one more target before I left him to his solitude: The core of Comet Linear C/2001 A2 at mag. 10 was visible in Sagitta, in the same field as Gamma Sagittae and M71.

At about 22:20, about 30 minutes before moonrise, I started home via. Mines Road toward Livermore. I compared the travel time on this longer, but hopefully faster route: I got home 10 minutes faster than it took me to drive out, but any traffic along I-580 or I-680 could have easily wiped out that difference.

I consider it a successful scouting expidition to a new observing site, even if I didn't set up my own 'scope to observe. If someone else is heading out there, I'll be happy to join them.

Reports | About Reports | TAC | About TAC | Join TAC