During the afternoon of Monday, Apr 12, 1999, I received the following alert from VSNET:
Dear VSNET colleagues: An amateur friend, Dr. X---, has informed me of his visual discovery of a possible SN (mag 12-13) in NGC 3294 (J2000: 10:36:15, +37:19:24) on 1999 April 11.2 with an 0.3-m reflector. The new object is reported to be near the SE end of the galaxy's disk, although I may have misinterpreted his report, and it could be at the NW end. Nothing is seen on the Digitized Sky Survey at either possible position. Can anyone check his observation? clear skies, Howard E. Bond Space Telescope Science Institute
I shared the information with other Physics faculty members here, and we decided to try to check the candidate that evening.
I arrived at the RIT Observatory around 8:00 PM. It was still light out (but not light enough, see below). A cloud bank sat on the western horizon, but never did come overhead. It was chilly. The wind was strong and gusty, perhaps 10 to 15 mph. It blew papers around if they weren't held down, and blew the blue tarp over the cabinet back and forth. Very annoying, and also very chilling. I think that the roll-off structure is ill-suited to use when the wind is even moderate; I might not open up in similar conditions in the future.
I attached the Meade Pictor CCD camera at Cass focus to the 16" Autoscope telescope. I used no filter. I tried to take twilight sky flats, but discovered that at 8:21 PM EDT, when the sun was only 7 degrees below the horizon, that the Meade CCD required a long exposure time to build up any kind of sky signal. For example, a 20-second exposure at this sun altitude yielded only 2000 counts above the bias level! A good sky flat has 10,000 or 20,000 counts above the bias, so my attempts were inadequate. I took a total of 9 flatfield exposures of 20 to 60 seconds, each with about 2000 counts above the bias. When I later combined them into a single median image, it was too poor to use:
Clearly, I need to start taking twilight sky flats while the sun is still above the horizon. I must begin working much earlier in the future ...
Eventually, it got dark. I focused the CCD on Pollux. It took a long time to find a good focus by trial-and-error. I found that a value of
T motor position = -26,775
yielded decent images.
Tracy Davis and Roger Easton arrived to help out, and Jim Kern came over when his students had left for the night. It helped a lot to have extra hands and eyes! We tried to set on NGC 3294 as follows:
So, we tried setting coordinates on mu UMa (which was only about 4 degrees from the galaxy), then moving to NGC 3294. We took a short exposure, and saw nothing on the CCD. Rats.
We then decided to use the Orion Short Tube as a finder. We placed the intensified video camera on the Orion, and hooked it up to the TV set. It took us a while to figure out how to adjust the brightness of the TV set (must use the remote control and adjust the "Picture" setting). After some fiddling, we were able to look at the TV set and see a field of about 0.45 degree in size, with stars down to about tenth magnitude. Very handy, but we will need to improve the mounting of the Orion on the Autoscope; it flops around quite a bit.
We moved to Regulus and set coordinates there. We placed Regulus at the center of the 16" field of view, and marked the spot on the TV screen where it appeared. Then, we slewed to NGC 3294 -- a distance of 17 degrees. Mirabile dictu, the telescope did its job: we saw the proper field stars on the TV screen! After just a little centering, we tried a 10-second exposure, and there was the galaxy. Rah!
So, we took two 70-second exposures, which weren't trailed appreciably. A single 310 second exposure was trailed, quite a bit. Here's a combined view of the two 70-second exposures:
The signal-to-noise ratio is very low in this picture; we need to take longer exposures, or, I guess, add together many more short exposures. I didn't get any dark images during the night (oops), so I couldn't subtract away hot pixels. I didn't apply a flatfield correction to the frame -- the flatfield's S/N ratio is too low.
Here's a reference image of NGC 3294 from the Digitized Sky Survey, side-by-side with our image:
The reference image has a supernova in it (SN 1992H, I believe), just west of the nucleus. But our image does not show any new point source in the galaxy. It doesn't show any point sources at all, really :-(
We closed up after acquiring the images of NGC 3294 -- it was still windy and we were all getting cold.
I sent in a negative report to VSNET around 11:30 PM that night. It was one of 3 negative reports I've seen posted. Below are a set of postings concerning this candidate to VSNET, with our message at the end.