Flats and Darks.

[Paul Repacholi <prep@prep.synonet.com>]

There has been some discossion about these and the WCS headers for
them.  The answer to that is, you do not put WCS info in them at all,
it is meaningless.

There was a good discossion of the topic of flats and darks in paper
from IRAF or Space Telescope. In summary, dark you can do durring
the day, so there is no problem with time to do them. Plus they
can be totally automatic.

Flats are a bigger problem. Dome flats are easier to do in quantity,
but they may well not be accurate. The time to get sky flats is limited.
But to get a master flat of good S/N you need lots of flats to make it
from.

In addition you need to make the few durring a session to monitor any
change in CCD chareceristics. With the higher temps the TASS CCDs run at,
and thhus the greater change in params per delta T it is more important
that it is with LN cooled cameras.

-- 
Paul Repacholi                               1 Crescent Rd.,
+61 (08) 9257-1001                           Kalamunda.
                                             West Australia 6076
Raw, Cooked or Well-done, it's all half baked.
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