Pictures taken at Oxford - History

We started taking astronomical images in the parking lot in front of Kennon Observatory in the Fall of 2002. We used an old SBIG ST-7 CCD camera mounted on a Meade 12-inch telescope.

The first results were quite disappointing. The telescope would not track correctly for more than 15 seconds; the focal reducer severely vignetted the field at f/3.3. Setting up for work took an hour and a half, and this alone strained the patience of studens.

Ever since then, we made step-by-step improvement in both equipement, software, and our knowledge of the many little tricks. We removed the office from the gap under the little dome, which dramatically improved seeing. Just imagine, having to work in a dome while someone else is running a heater two floors below you. The dome used to act as a chimney, and stars were shaking like crazy in the telescope.

We installed air conditioning, and now we keep the dome's temperature as low as the expected ambient tempeture of the coming night. We still have bad seeing (something like 2 as), but this is certainly an improvement.

In 2004, we purchased and installed SBIG's so-called AO7 adaptive optics device - a little tiltable mirror that purportedly corrects for seeing. In fact, it works as a wornderful automatic guider; we could switch to an optically reasonable f/6, and could afford as long exposures as 20 minutes without interruption. We took many pretty images oof deep-sky objects with this setup.

In the same year , we started an honors section in astronomy, and made astronomical image taking part of that laboratory. While everyone was ertainly impressed by some of the colorful pretty pictures we produced, we also found increased support for further technical improvement.

A great step towards professional quality work was the purchase of a Paramount ME mount and of an ST-10 camera in 2007. Not having the funds available to buy a good quality telescope as well, we installed the old Meade 12-inch Schmidt-Cassegrain on the now state-of-the-art mount. With a decent quality focal reducer we work at f/5.7 now, and the field is 20' x 30'. Indeed, this setup puts as large a field on the CCD as the scope can image at all, at full resolution.

At this point we take more than ten pretty pictures a semester; our total exposure times can be as long as five hours. We can occasionally detect stars down to 20 magnitudes; some of the galaxies and nebulae look quite spectacular on our student picutes.

As to future planes, investigations are underway to battle the "bottleneck": star sizes on long exposure images are still 3-4 arc seconds, too large. A new, 17-inch telescope is about to be purchased, which is supposed to make a great difference.