Rancho Canada del Oro 28Jul06

by Bill Parkhurst

The Santa Clara County Open Space Authority (OSA) hosted its first Stargazing Night at their Rancho Cañada Del Oro Open Space Preserve on Friday July 28th. The preserve is located in the foothills just south of Calero County Park. I heard about this event through SJAA. Apparently, the OSA would like to encourage more public use of their property. There were a couple of very nice OSA people at the paved parking lot (staging area). They had us set up our telescopes in an open grassy area just beyond the parking lot up a dirt road, and just over a slight hill. The grass area has lots of room but is surrounded by hills and trees, so the horizons are not very low. The hill to the North did block a lot of the San Jose light dome. The trees to the South covered all but the very top of the teapot in Sagittarius. The site got pretty dark considering how close we were to San Jose. The Milky Way was fairly visible. I did not do a good star count, but I would estimate NELM between 5 and 6.

The OSA people were very interested in how to accommodate amateur astronomers, and there was talk about exploring other sites at higher elevations. I think there were about six scopes set up in the grassy area, one telescope was in the paved parking area. A hand full of public non-scopers also attended. Everyone packed up between 12:00 and 12:30am.

No wind. No fog. Got chilly as the night went on. Some light dew starting about 11:00pm. Finder fogged up at 11:40 and had to be warmed.

Observed with 10 inch reflector on Dobs mount (XT-10).

We showed the hand full of public attendees some of the standard summer highlights. I showed some of them the setting crescent Moon; Jupiter; M13, M4, Glob clusters; M57 and M27 Plan neb. When showing M27 to people for the first time, I like to ask them what shape they see before I give then the Apple Core name for the M27 nebula. I asked our OSA guide what M27 looked like to him. He said it looked like the Bat sign that is flashed into the sky over Gotham city to call for Batman's help.

Notes from my log:

Jupiter - shimmery; three moons visible.

M57 - PN (Lyra) - Nice view. Darker in middle. Used 48X, 120X, and 190X. UltraBlock (UB) narrowband filter improved contrast.

M27 - PN (Vul) - Viewed at 48X and 120X. Used UB filter. Classic shape.

M4 - GC (Sco) - Viewed at 48X and 120X. Nice 3-D view with stars of various magnitudes resolved throughout cluster.

NGC 6144 - GC (Sco) - Found at 48X between M4 and Antares. Viewed at 120X also. Only one star resolved.

M13 - GC (Her) - Stars resolved throughout. 3-D depth effect. Irregular border. Viewed at 48X and 120X.

NGC 6207 - Gal (Her) - Saw small galaxy next to M13. There are two reference stars near M13, one on each side of M13. NGC 6207 is just beyond one of these reference stars. Galaxy was a small, faint oval shape at 120X. Bright point core visible part of the time.

M12 - OC (Oph) - Lots of stars resolved. Hint of many more unresolved stars in middle of cluster. Nice object. Very irregular shape. Not round. Three bright stars bordering object. Explored middle of cluster at 380X. View at 48X and 120X was better.

NGC 6118 - Gal (Ser) - Jumped and hopped from M12. Did not see. Too faint. Used Joe's computer maps to confirm correct star field location just above stars Yed Prior and Yed Posterior.

M8 - OC and Lagoon Neb (Sgr) - Object was naked eye visible. Viewed at 48X. UltraBlock (UB) filter brought out much more nebulosity with a dark lane between the open cluster and the brightest part of the nebula. Magnified the small, but brightest, area within the nebula to 120X and 190X - also using UB filter. Bright area showed some shape but did not really look like an hourglass.

NGC 6544 - GC (Sgr) - Located just below M8. Small and faint glob cluster. No stars resolved at 48X, 120X, or 190X. At 120X, cluster center looked star-like occasionally. Hard to determine overall shape of dim object. Maybe triangle?

NGC 6553 - GC (Sgr) - Located just below NGC 6544 and M8. Easy to find - bright hazy spot seen in 25mm eyepiece (48X). Glob cluster is near an arc of three stars below M8. No stars resolved at 120X or 190X. Irregular shape. One bright star on edge of cluster.

M20 - Trifid Neb (Sgr) - Faint nebula seen at 48X. Better view with UltraBlock (UB) filter. Good view at 120X with UB filter. Three-part nebula created by intersecting dark lanes. Two close stars in middle. Object filled most of 10mm eyepiece field of view (24').

NGC 6568 - OC (Sgr) - Hopped from M20. Open cluster spread out through 10mm eyepiece field of view (24'). No remarkable shapes or chains. Viewed at 48X also. Scattered cluster. No shapes noted.

NGC 6583 - OC (Sgr) - Located just below NGC 6568 near M20. Saw a faint blur at right location using 48X magnification. Same blur at 120X. No stars resolved.

Also looked at M5 and M92 Glob clusters; and NGC 457 (Owl cluster).

Bill Parkhurst.