The Occultation of a 13.7 Star by Asteroid (87179) 2000 ON7 for 0.9s

Sun eve March 15, 2026 at 9:24:30pm

OWc page

 

This is a faint star, but for 0.7s it should be do-able. It's at high altitude so care will be needed to not hit the Watec against the base. 20 min before the event, the altitude is 76 degrees. For me, I'm going to try hard to NOT use the 0.5x and diagonal. It's just not as sensitive. For Jordan, it may be the best choice though (did I give you a 0.5x and diagonal??) It will be very close. Best to GoTo of course with the eyepiece and diagonal and only put in the Watec when it's safe to do so.

Alt=74, Az=225 in Gemini

     

 

Results:

Richard Nolthenius

Got a recording at 8x in the standard straight-through f/3.3 configuration, from home. The star was in the west during the event, so I knew that it would be too high at pre-20min to go and so I held off trying to mount the Watec until later. But making sure I was on target in the Q70 eyepiece so I could swap it in and be ready quickly. Then, when I did, it still wouldn't go, but I could see that it WOULD go if I could insert the Watec into the adapter's 1.25" sleeve before trying to attach the adapter to the f/3.3 and telescope. That's what I did, and then the bottom of the Watec missed the base. So, I left in the f/3.3 but unscrewed the 1.25" adapter, inserted the Watec and tightened it in the sleeve, and then screwed that on to the end of the f/3.3 and clearence let me do that. Only this sequence allowed clearance, not the usual screw on f/3.3+ adapter and then insert the Watec.

Difficult event, but most consistent with a miss. 0.7s would be, for 8x, 17 frames or 4 integrations, consecutive all at zero. There are many single frames not far from zero, but no consecutive frames. Filed as a 'miss'.

       

 

Kirk Bender

I got a recording of 2000 ON7 at 32x from home, looks like I had an event. I got on target with the camera and 0.5x reducer in the diagonal, then shortly before the event I tried to swap out the diagonal and put it straight in, but it was still too high.  I put the diagonal back and got back on target just in time. I just hope I get at least two integrations at 32x.