About the CCD Images

The images available through this web site were taken with an ST-6 Charge Couple Device from the 21" Cassegranian reflector located on the campus of the University of Arizona. This optical system has a limiting magnitude of approximately 17.5 (on a 90 second exposure) and a focal length of 8001mm.

Because the telescope is located in the center of Tucson, light pollution has affected several images. The method I used to "flat field" was the following. Because of light sources in the city, the sky is not of uniform brightness, therefore flat fielding with a uniform light distribution proves insufficient. So I aimed the telescope off source and moved the telescope in R.A. and Dec. for the length of the exposure I wanted to flat field. By using dark areas of sky near the target object, sky inconsistencies can be removed. This method, however, is not technically a flat field.

Unless otherwise noted all images are black and white. All times listed are Universal Time

A note to Netscape users, please be sure that under general preferences - images, that "Dither" is selected. Other options may distort the images.