Siegena Occultation - Jan 13, 2007

Observer: Richard Nolthenius (831) 479-6506, rinolthe at

Asteroid, Star: (386) Siegena, TYC 4895-01630-1

Telescope: 10" Meade LX200 f/10, Alt-Az, 22mm Nagler

Location: Calaveras Road near I-680 north of Fremont. Lat=37° 34' 49"N, W Long=121° 51' 57"W (NAD83/WGS84), elev 300ft.

Method: Voice/WWV/tape recorder

Sky: clear, decent seeing, star+asteroid merge visibility: about 0.8 magnitude above mag limit. Solid.

Timings: Jan 13, 2007 UT (miss)

begin: 07:24:30

end: 07:28:00

Comments: Got the PC164c and camcorder set up and stars focused.... sort of. Turns out using the T-to-C interface adds too much distance from the f/3.3 to the PC 164C, and so the stars were horribly distorted and this wrecked the magnitude limit. Target star invisible. I need to use the Meade-to-1.25" adapter in the future. It's on order. So, I went visual. But the mag drop was only 0.45 so it was hard. I feel fairly sure I saw a miss, but it's possible that a short event lasting a couple of seconds or less could've been missed. How short will depend on when/if I get a look at Derek Breit's video recording of his 9 sec occultation. But most likely interpretation of his event (predicted central event was 17 seconds) is that we had a strong north shift and he was closer to the southern limit and I had a big miss.

Here's my Excel report, and there's no other observations and no sky plane plot.