Saturday, June 16, 2001

Saturdy Night Observings

At Henry Coe State Park Saturday night, Mars was excellent around transit. I had my 8" f/6.8 Dob stopped down to about 3" and riding on an Equatorial Platform. I borrowed 3, 4 and 6mm Radians which all gave very pleasing views. The 6 was best, but even at 458X (with an effective focal ratio of f/18.3) plenty of detail was visible. The biggest surprise came when I used my 18" f/4.5 Obsession at full aperture. The best view was again with the 6mm Radian at about 343X, but even the 3mm performed well at almost 680X.

Two filters were tried. A red filter produced the most detail on the dark southern regions of the planet. However, I felt other details were lost. A neutral density filter produced what I felt were the most pleasing views, cutting the brightness of the planet down and revealing the nice subtle orange-red color of the brighter areas of the surface, while the darker southern sections had the color of a port-wine birthmark.

The only thing that could have made Mars appear better would have been an aperture mask on the 18". I'll do that next weekend.

Deep sky targets at Coe were good to the north, south, west, excellent to the southeast, east and northeast. Conditions were near ideal with low RH, calm to light breeze and warm temps. We also had an excellent turnout with 20 or more scopes.

The obvious light domes were from San Jose, Hollister and Gilroy, and in the distance Salinas just south of Fremont Peak.

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