The Occultation of a W=13.9 Star for 1.4s by (2776) Baikal

Fri eve Sept 11, 2026 at 8:31:00pm

OWc page

 

This is a faint star, but lasts 1.4s which should be long enough to get some points at minimum, in a dark sky. I will plan to drive up to darker skies; maybe up the coast or from the Arboretum at UCSC?  Probably too much light pollution from home. I'm hoping Danika will want to join me and get her first evnet on our 2nd Unit scope.

Alt=33, Az=199 in Ophiuchus, 4 degrees beneath the bright star "crook" in Serpens on the left side of Ophiuchus

     

 

Results:

Richard Nolthenius

Danika wasn't available, and I feared local lights would make the sky too bright at home, so I drove up behind the Arboretum, to the dirt road leading off back of the bike path, to another dirt road leading up the hill with an excellent view in all directions - dark and good for future reference. But the marine layer was dense and high humidity, and scattered light was a problem and mediocre seeing. At 32x, star was barely visible.

         

Kirk Bender

I don't see an event for Baikal, 16x from home. I could not see the target reliably on the screen, but at 1.4s max didn't want to use 32x and only get 2 integrations, but maybe I should have used 32x anyway. The target was dimly visible on a PyMovie finder, so I could place the aperture on the right star, but there is another star very close so I used aperture size 11.  I tried several mask sizes, but PyOTE could either not find an event, or else find spurious low confidence events far too early. OW cloud indicated there were nearby stars and for a 8" radius the drop would be 1.7. Using mask size 2.4, the PyOTE detectability test said an event as short as 2.14s would likely be detectable for 1.7 drop, and for a max 3.7 drop for the star would be detectable for 1.6s. It looked clear, but I think though this event was probably undetectable for my data, given the twilight and atmosphere.  Rank was good, and we were well within the path so we should have got an event with the right aperture and conditions.