April 25, 2009: D.A.R.C. Observatory

David Cooper

I decided to try a new observing site this past Saturday, namely D.A.R.C. Observatory, about 23 miles south of Los Banos and about 12 miles west of I5 on the way to Mercey Hot Springs. This is a private site owned by Lee Hogland who welcomes observers every clear new moon weekend. From my house in Palo Alto, it took me about 2 hours of driving to get there and meet up with Peter Natscher at the gate. When I arrived, the conditions were clear but very windy with gusts that I’d estimate at up to 20 mph. So when we arrived Peter and I retreated indoors to eat dinner and wait for things to calm down.

Just after sundown, the wind calmed enough for everyone to set up for a long nights observing. There were probably about a dozen or so folks present, with a mix of imagers and eyeball-to-eyepiece observers. Unfortunately, toward the end of astronomical twilight, the wind picked up again with a vengeance – forcing most of the big Dob owners to tie down and head inside to watch TV. Because my AP155 is mounted on a robust AP900 mount, I was not much bothered by the wind and could observe during this time – a solitary observer surrounded by a field of large aperture overbuilt wind socks – large Dobs do provide perfect wind direction indication in high winds!

Fortunately, the wind died down for good by 11 PM and we could all observe from fairly dark skies. Although the skies were clear, the seeing and transparency was inferior to Dinosaur Point last weekend. Nevertheless, I continued to work on my H400 list and was able to bag an additional 18 of them in Leo Minor, Ursa Major, and Virgo before going to bed at around 2:30 AM. Some of my observing notes follow.

3605/3607/3608/3599 – this nice grouping in Leo is called “the pendulum” by Mark Johnston and is aptly named. In the 0.6 degree field at 103x in my 10.5 mm Pentax eyepiece, I can normally view all 4 galaxies with 3599 as the pivot point for the three “swinging” galaxies 3605/07/08. However, unlike last week where all 4 were easy from Dino, 3605 did not appear at all in my scope! Observing conditions do make a difference. Perhaps I need one of those wind-indicating Dobs after all.

3395/3396/3413/3430 – a nice galaxy grouping in Leo Minor: 3396 and 3395 just kissing with 3413 and 3430 as innocent bystanders. Did not have enough horsepower to see the fainter fifth galaxy 3324.

3432 – a sliver galaxy with a somewhat irregular appearance at 103x

3877 – another slender needle galaxy with a distinctive, but non-stellar, core, 103x

3344 – a nice face-on galaxy near two bright field stars, non-distinct core, 103x

M59/M60/4647/4638 – could bag all 4 of these gems in Virgo with bright M60 (4649) overpowering the feeble glow of nearby 4647. Indeed powerful M60 overwhelms M59 as well and both galaxies have distinctly bright stellar cores. By contrast, I could not perceive any core to either of the other two galaxies – both are gutless and faint.

M89/4550/4551 – M89 appeared as a soft glowing circle of haze with a bright stellar core at 103x. In the same fov I could discern fainter 4550 and 4551, both as featureless faint fuzzies.

Saturn – could discern 5 moons (but not Enceladus) but little surface detail as the seeing for most of the night was very poor – by several standard double star metrics, I estimate the seeing at around 1.5 to 2 arc seconds for most of the night.

Although the conditions were, as they say in the mortgage industry, subprime, it was still a satisfying evening and a welcome opportunity to get away from the grind of the everyday world. Speaking of grind, I was pleasantly surprised to find out that the Sharks managed to win a game while I was not observing them. That means they have won both of their recent playoff games when I was not watching – perhaps they are sending me a message. I may go on not observing them again on Monday night.