On the night of Nov 14/15, 2025, under decent-to-miserable conditions I acquired astrometry of two stars: GX And and Ross 248.
I also attempted to observe a low-probability occultation event, in which the TNO (119979) 2002 WC19 and/or a possible satellite would pass in front of the star UCAC4 557-032051. Unfortunately, clouds arrived, and I was unable to make any useful observations.
GX And is a nearby (binary) star which will be the target of a parallax project at some point. One of the two components is bright -- about mag V = 8 -- so one must use short exposures to prevent it from saturating the detector. That may mean that this system isn't as easy to measure as Ross 248 or some others.
These observations involved:
Notes from the night:
The object is currently close to this position:
RA = 00:18:28.4 Dec = +44:01:31 (J2000)
but it does have a very high proper motion.
A chart of the field is shown below. The size of the chart is about 41 x 27 arcminutes. The noisy area at right (West) is the shadow of the guider's pickoff mirror.
The two components of the GX And binary sit inside the box. I've marked the location of several comparison stars as well.
star UCAC4 B V r ----------------------------------------------------------- A 671-001473 9.939 9.790 B 670-001639 9.413 8.472 C 671-001509 12.712 11.421 11.001 -----------------------------------------------------------
I took a photo of the finder TV's screen when pointing to GX And; this could be a useful reference for the future:
Using the same techniques as described for earlier nights, I matched detected stellar positions to the Gaia DR2 catalog. In this case, I used only stars within a "smaller" subset of the full catalog around the target, those no more than 10 arcminutes away from it.
The target is moving to the upper-right with time, and clearly shows the back-and-forth motion due to parallax.
This is one of the stars that a capstone student may study over the next year in a project involving parallax. Ross 248 is a relatively faint red star surrounded by many other stars of similar brightness, so it's a good candidate for high-precision parallax measurements.
These observations involved:
The object is (currently) near position
RA = 23:41:55.27 Dec = +44:10:06.38 (J2000)
A chart of the field is shown below. The size of the chart is about 41 x 27 arcminutes. The noisy area at right (West) is the shadow of the guider's pickoff mirror.
I've marked the location of several comparison stars.
star UCAC4 B V r ------------------------------------------------------------------------- A UCAC4 671-120730 12.617 10.689 B UCAC4 671-120688 C UCAC4 671-120749 10.987 10.663 P kappa And 4.06 4.14 --------------------------------------------------------------------------
I took a photo of the finder TV's screen when pointing to Ross 248; this could be a useful reference for the future:
In order to get the best results for Ross 248, it is necessary to use only a subset of the stars in the camera's full field of view. For this evening's data, I chose the "intermediate" subset, and restricted matches to those stars within about 11 arcminutes of the target. It helps to limit the measurement of stars in the images to this same region, too.
Here are the positions I've measured so far. The most recent measurements are at the bottom of this plot.
I heard about this event from astronomer Anne Verbiscer. She sent a message to the IOTAoccultations E-mail list asking observers to try for this event. More details can be found at the Occultwatcher page:
This was a low-probability event, since the shadow was 400-600 km in diameter, but its track had an uncertainty of 10 times that size. Still, it was worth a try.
I planned to use the 12-inch telescope with no filter. The target star has a magnitude of V = 14.2, similar to that of the target of (19521) Chaos on Sep 30, 2023. An exposure time of 1 second sufficed for that object, so I was going to try using a similar exposure on a sub-frame centered on the object.
I found the field and started tracking it around 11:07 PM, about two hours before the event. As the clouds thickened, I increased the exposure time from 1 second to 2 seconds -- that should have been fine, as the predicted duration of the occultation was much longer.
Below is one frame, taken at UT 05:56:53, perhaps the best of the entire run. I've marked the target with crosshairs, and circled two brighter stars which could have been used as photometric references.
Unfortunately, there were perhaps only 10 to 20 other frames which showed the target star clearly, over my set of 469 images spanning 21 minutes. It's impossible to say anything about an occultation, or lack thereof, based on this fragmentary data.
Sigh.