The Occultation of a 11.5 Star by 2001 XY26

Thur eve Apr 3, 2025 at 8:32:45pm

OWc page

 

This event is poor rank, but in a good direction for me at home. I'll give it a try. Kirk is also in good position from home. It's bright, but will require 2x or 1x for the 0.3s duration

Alt=28, Az=107 in Virgo. Very close to NGC 4043, a tiny faint SB0 galaxy. Use it just to avoid having to type in all the RA/Dec numbers if you're in a hurry

 

     

 

Results

Richard Nolthenius

I recorded this from my carport, at 2x setting. Target was easy, seeing was good and no wind. Looks like a clean miss. 0.3s corresponds to 7 integrations dropping to zero, at 2x. Clearly this was a miss.

     

 

Kirk Bender

Observed from the entrance to the Long Marine Lab, at 1x.

I got a noisy positive for 2001 XY26, 1x on Shaffer road by the marine lab entrance. PyOTE found a .25 sec event about 1 sec later than predicted, NIE test was 2.0 sigma distance. It gave a mag drop of 1.378 vs predicted 6.2, but target curve was not much above background.

RN: I notice that there is a 0.25s dip in the reference star at exactly the time of the PyOTE detected dip in the target, of similar amount. I believe there's a strong possibility that this reference star dip was not properly accounted for in the recommended metric smoothing procedure in PyMovie, whereby we smooth until the overall flatness of the light curve of the target star outside of the event, has least noise scatter.

magDrop report: percentDrop: 71.9  magDrop: 1.378  +/- 0.930  (0.95 ci)

DNR: 1.35

D time: [03:32:45.1604]
D: 0.6800 containment intervals:  {+/- 0.0221} seconds
D: 0.9500 containment intervals:  {+/- 0.0830} seconds
D: 0.9973 containment intervals:  {+/- 0.2089} seconds

R time: [03:32:45.4107]
R: 0.6800 containment intervals:  {+/- 0.0221} seconds
R: 0.9500 containment intervals:  {+/- 0.0830} seconds
R: 0.9973 containment intervals:  {+/- 0.2089} seconds

Duration (R - D): 0.2503 seconds
Duration: 0.6800 containment intervals:  {+/- 0.0399} seconds
Duration: 0.9500 containment intervals:  {+/- 0.1159} seconds
Duration: 0.9973 containment intervals:  {+/- 0.2563} seconds

     

RN: My recommendation is that this submission to IOTA be labelled "unsure" and that the event be labelled "maybe", and that a mailing to IOTA should recommend looking closely at KB's light curves and the ref star dip at the event time, smoothed over. However, even a point by point subtraction would still, I believe, show a shallow event at Kirk's detection. Is it real? Not sure.