The Transit by Mercury

May 9, 2016

The first Mercury transit in 10 years, came on a rough day. Monday mornings I teach; still, I'd hoped to get up to UCSC at sunrise to watch the sun rise over the distant Santa Cruz Mtns crest with Mercury. The day opened with heavy fog, and a quick look at the satellite imagry showed it went right up to 3,000 ft elevation. Too hard to get to, for having class start at 9:30am, and I was still pretty tired from a night of fine food and wine with Kent. I figured it may clear in time to show my Astro 4 class the transit from outside the classroom, and had packed the scope and Nikon and eyepieces in prep. But by the end of class, it was still socked in. Plan B was to drive up to Summit Store and meet Karl - fastest pathway to high elevation from Cabrillo. The new iPhone smoothed my rendezvous with Karl, and I pulled over at Radinovich Ranch. Clouds - still. Got there at 11:20am, so we had 20 minutes to set up the 8" Celestron and get a look and snap a few photos before the end at 11:42am. We did get a brief view of Mercury, then I tried to get at least a few shots with the Nikon through the 2" diagonal on the back of the scope. But the fog only gave a few seconds of thinning where the sun got through the Thousand Oaks solar filter, and I guess wrong on which direction would have Mercury on it.

I tested the setup the afternoon before; finding I could get a high magnification image through the 8" f/10 Celestron. However, I could not reach focus with the existing Nikon T-Ring + barrell on the 8" f/4 SNT. I went with the Celestron; loading it into the RAV4

The sun, and a prominent sunspot group, while testing at the observatory

Dawn was hopelessly foggy, so I went off to class figuring it would be burned off and clear by 11am when class ended. Nope. So Plan C went into effect; a mad dash up Old San Jose Rd, on the iPhone with Karl to coordinate. I gained a little more elevation by continuing to Radinovich Ranch at the foot of Mt Bache Rd. Some patches of blue had been happening in the last mile and I was pretty optimistic we'd get some views and pictures.

Karl helped me find the sun by using a piece of paper to center the projected image from the finderscope. I had on the Thousand Oaks solar filter, giving a very faint orange sun during the better moments, and only a bright orange image for a few seconds during the entire 20 minutes from the time we pulled in to the end of the transit. One of those brief moments was right after setting up, and Karl and I at least got a nice visual view for a moment.

Nikon D7000 now mounted, and I did see the orange sun at a few brief moments. We had to continually re-find the sun, which hurt efforts given how few were the moments of seeing it at all. I did snap a few shots, guessing where Mercury would be.

Taken a few minutes before the end of the transit. The wrong side of the sun, alas. That's a sunspot, not Mercury


This was our sky - passing fog, and a sun with about 5 magnitudes of extinction more or less.