From: Henry Spencer <firstname.lastname@example.org>
Subject: telescope cooling (was Re: lunar resources)
Date: Wed, 21 Feb 1996 16:43:04 GMT
In article <email@example.com> fcrary@rintintin.Colorado.EDU (Frank Crary) writes:
>>: ...For cutting edge work, you need
>>: to keep the detectors at cryogenic temperatures...
>>Cutting edge work refers here to IR.
>I'm not so sure of that. Low temperatures are certainly more
>important at long wavelengths, but most of the visible
>wavelength telescopes I'm aware of also use cryogenic
>temperatures for the detectors...
While you *can* run CCDs (the choice for almost all modern visible-light
astronomy) at room temperature, they perform considerably better at LN2
temperatures, so the professionals routinely cool them that way.
>>...The Hubble Space
>>Telescope manages to do 'cutting edge work' without...
>I'm not sure of that. In space, there are a few tricks to
>get low temperatures without active cooling. I'm not
>familiar with the details of Hubble's design...
The CCDs in the original WFPC ran at -95C using radiative cooling. I
believe the situation is similar in WFPC2. I'm not sure about the other
Space will not be opened by always | Henry Spencer
leaving it to another generation. --Bill Gaubatz | firstname.lastname@example.org