On Thu, 21 Apr 2005 15:35:33 +0200, Jan Vorbrüggen wrote:

Is the raw data from "all" exposures routinely saved over the years? A
particular target that is observed this year, last year, 10 years ago?

In the case of the HST, I'm pretty sure you can get the raw data even
from the first images. At least semi-recent stuff is regularly
re-processed when, for instance, new algorithms for defect removal etc
are implemented or just the calibration constants improved. As computer
storage is not a big cost factor anymore, and the raw data is only a
small fraction of all the data in any case, I can't imagine anybody not
archiving the raw data "just in case".


I've heard that the limiting factors wrt Hubble's current life span are
the batteries or the gyros. The batteries being an obvious one, while the
gyros may not be. If they are just being used for attitude determination
during maneuvers, and not the actual maneuver, it should be possible to
extend it's life so that the batteries or orbital decay are the limiting
factors.

Using a wide field camera and decent star map, I would think it would be
possible to use a visual attitude determination algorithm for maneuvering
the Hubble between targets. As the Hubble rotates away from one target, it
could determine it's attitude and attitude rates, then make adjustments
along the way as other stars come into view, and get close enough to it's
new target to acquire it. Kind of like using an old fashioned approach to
finding it's way from one target to the next.


--
Craig Fink
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