CCD's are analog, but the data gathered from them are often immediately converted to digital information for storage, just like in digicams. I'm sure that's what the Hubble does.
There's a diagram and explanation of the BIMAT system here: http://www.lpi.usra.edu/resources/lu...oduction.shtml
Originally Posted by ben-s
CCD's are analog devices, as are the chips in D cameras. The D part happens in a converter. Un-digitized output contains the most information, but it has to be managed, and that usually involves a computer.
Originally Posted by bobwysiwyg
I have a very expensive video camera that makes very good looking pictures that uses CCD's but is fully analog. It is completely possible for an imaging device to be fully electronic, but not be digital. Many people don't realize this. Hubble may be an example of that- the digitizing may take place on the ground. IDK for sure, but it would make sense to have the most unaltered information available, and the highest resolution of anything is always analog.
I may be wrong but last upgrade to the Hubble's computer system was an Intel 486DX chip. The
first with built-in math co-processor. The Hubble runs no background crap, Windows, e-mail, screen
saver, pretty pictures. It just crunches numbers. Wonder if next upgrade will be to an Intel Pentium 1 ?
I'm still running a Pentium-Pro myself. I don't use computers for photography or music, just for
Where do you think the last of the Ektar 25 got to?
The 486 processors in the Hubble are also radiation hardened, so they're not just off-the-shelf, consumer grade components. I think Intel ran a small, specialty Fab line of these products for government/military space applications.
The government has intel and others make a whole series of specially hardened computers which are designed to withstand the environment of space and the EMP of nuclear war! The computer is essentially encased in a Faraday cage for additional protection over what is afforded by the chips' design.
All sensors, CCD or CMOS are analog. Both types have been around since the 1960's.