Path: utzoo!attcan!uunet!samsung!usc!ucsd!ucbvax!agate!darkstar!helios!terry From: terry@helios.ucsc.edu (Terry Ricketts) Newsgroups: comp.sys.amiga Subject: Re: summary re: amiga, ccd, astronomy image-processing Message-ID: <7049@darkstar.ucsc.edu> Date: 20 Sep 90 20:55:43 GMT References: <1160@mpirbn.mpifr-bonn.mpg.de> <28827@nigel.ee.udel.edu> <992@ucsvc.ucs.unimelb.edu.au> <28045@swrinde.nde.swri.edu> <15264@shlump.nac.dec.com> Sender: usenet@darkstar.ucsc.edu Reply-To: terry@helios.ucsc.edu (Terry Ricketts) Organization: UCO/Lick Observatory, Santa Cruz Lines: 23 In article <15264@shlump.nac.dec.com> guineau@wjg.enet.dec.com writes: >I haven't been following this thread so this may have already been answered. >I was under the impression that CCD's were not 'cumulative' light collectors >and so are useless for dim things like deep sky. CCD's are very good at accumulating light, and don't destroy themselves if they become saturated (as the older TV tubes used to do). Simply letting the light collect for awhile & then clocking the image out lets you see much dimmer. Of course you will need to cool the CCD if you want to do this for any extended period of time, like several seconds. Otherwise the noise will swamp the signal. You also need a good input amplifier which is not present in most camcorders. We have built a number of CCD cameras for use on the large telescopes at Lick Observatory that 'integrage' the image for as long as several minutes to see very faint objects. In tests in our dark room we have been able to detect something written on the outside of the door when illuminated with a flashlight. The camera is literally looking through the door. | Terry Ricketts | Internet: terry@helios.ucsc.edu | Senior Electronics Engineer | loel@helios.ucsc.edu | Lick Observatory Electronics Lab | Phone: 408-459-2110 | University of Calif, Santa Cruz |