The Nemausa Occultation

Oct 22, 2017

The most recent prediction showed a north shift, alas, and so I'll have to drive up to Montara to have a good shot at getting the event.

4:06:28am central occultation at Montara. Changes slowly, altitude only 21deg in Hydra in east.

Preston page

Eyepiece view in Q70

LCD view. I've noticed so far that the Celestron Nextstar 8SE doesn't go-to quite as perfectly as does the Meade LX200gps. Maybe too soon to say, maybe need more perfect time input etc. But seems to be off by about 1 field rectangle.




Conked out around 11pm, thinking I'd wake again soon. Hadn't set alarm or thought about it. Woke up at 2:40am instead of hitting the road at 2am! Rushed, got out the door in 10 minutes, made it as far as the Hwy 1/StageRd intersection just north of San Gregorio. Got set up OK, scope aligned successfully on the first try. Got good data... but looks like a miss. Recorded at 8x integration.

LiMovie .csv file

The event should have centered on frame 1730 or so. I see nothing unusual. I don't see anything in the comparison star either, but might try again using the brighter and closer 9.5 mag star, in case the higher S/N and also the closer phasing in characteristic turbulence length makes an improvement. Worth it for the education if nothing else. Use 5/7/25 circles in LiMovie, 'drift', no tracking star used, just target A and comparison star C, no linked tracking as predicted D was 0.8 magnitude so could drift on target the whole event.

My observing site is the red cross, at the top of Stage Rd near Hwy 1.