This event looks like a good opportunity to set up the 12" Scope at Cabrillo Observatory with the Watec camera. The event, at full duration, is do-able with an 8SE scope. Alt=29, Az=193. At the Observatory, it will be over Water Tank Hill, to the right of the water tank. I'm pretty sure that's good enough for 29 degrees altitude. I'll bring my 8SE gear just in case I have to move elsewhere.
One problem: There's a similar magnitude star only 3" away, so reducing it will have an additional challenge
 |
This is for the 8SE scopes with the Q70 eyepiece, as usual. |
This chart is oriented for an equatorially mounted SCT, such as the 12" at Cabrillo. The field of view will be less than 1/2 as big, if the f/6.3 is used, or about 2/3 as big if the f/3.3 can be used. |
This is for the 8SE scopes |
Kirk and I both got data on this difficult event.
I observed near the front door of Cabrillo Observatory, under good dark skies. Target star was a lot dimmer than I thought it would be. I observed at 8x to get the time resolution for this 0.8 sec event. Target was not far from M22 in Sagittarius. The R magnitude is 12.7, but the G magnitude was 14.2, so a very red but very faint star. I used a TME aperture, as the only way to get a good location on the target from frame to frame. In the finder frame, the nearby star is not even visible. The target star is clear, lines up precisely with the neighborhood geometry, so I'm pretty sure I was monitoring the target and not a nearby star. I used a 111 frame fourier stack.
I'd hoped to get the 12" scope on this one, but the backfocus needs some new adjustments or gear that I didn't have time for, so set up the 8SE.
 |
Ref1, ref2, and target all had TME apertures. |
Target light curve of the TME aperture. |
"no-star" sky level, picked carefully at a blank part of the sky |
Vertical line at the predicted occutation time. |
A theoretical square wave light curve for the target with a maximum length occultation at the predicted time. The sky level is below, and a full disappearance of 3.6 magnitudes would only go down to "sky", which was above the zero level, as shown. While a very short event could be missed, there's no hint of any even in any nearby point, most consistent with a "miss". |
The rank was not high, but not terrible either, and my position inside the shadow path should have produced an occultation. However, my and Kirk's miss are not strong arguments for an orbit not reasonably described as the one used here for the predictions.
Kirk's data is also consistent with a miss, but at 16x integration, so only 3 integration points would lie inside a max total occultation.
