On the night of Aug 01/02, 2023, under mediocre conditions, I acquired images of
All data was taken with the 12-inch telescope and ASI camera. The results were okay. V347 Aur still appears to be quiescent.
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:
Notes from the night:
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.
Here are the positions I've measured so far. The most recent measurements are at bottom right.
Like Ross 248, GX And is a nearby (binary) star which will be the target of a parallax project in the coming year. 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.
On this night, for GX And,
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, using all the stars in the "intermed" reference set.
The target is moving to the upper-right with time, and clearly shows the back-and-forth motion due to parallax.
V347 Aur is a young stellar object (YSO) which undergoes semi-periodic outbursts. I'm part of a team of astronomers who have applied for (and received) time on the XMM-Newton X-ray telescope to study this object in the fall of 2023. We have organized an observing campaign with the AAVSO to monitor the object in the optical in order to determine when the outburst begins -- if it begins! Our prediction is some time in mid-August, 2023.
The position of the variable star is
RA = 04:56:57.02 Dec = +51:30:50.9
At quiesence, it has magnitude V = 16-ish, but can rise to V = 12 in an outburst.
Here's a chart from the DSS2 Red plates, 0.6 degrees on a side.
The picture below, based on a stack of images taken on UT Jul 23, 2023, shows the area in the red box above. The variable is at its quiescent level in this image.
I've marked the location of several comparison stars.
star AAVSO ID B V ------------------------------------------------------ B 140 15.134 14.001 C 127 13.617 12.660 D 154 17.491 15.361 --------------------------------------------------------------------------
Here's a picture of the guider TV when pointed at the field (pointed slightly to the left of the variable, actually).
On this run, a stack of 29 images, each an exposure of 30-seconds, showed the variable clearly in V-band. I made a stack in the B-band, too, using 25 images of 30 seconds each, but the variable and its comparison were JUST BARELY detected. I wasn't able to make any sensible measurement in B-band. The clouds and bright moon-lit sky are partially to blame, as is the relatively large airmass.
I measured a value of V = 16.17 +/- 0.10 and submitted it to the AAVSO.