Date: Tue, 14 Sep 2004 10:48:03 -0600
From: Dan Long
Subject: Secondary Acuator Tests from 53262
    From the tests done last night, it looks like the D actuator only
just barely exceeds the limit at zenith, and in some cases doesn't
quite reach it.  The limit is +/-18000 and in the three slews at
different focus values during the evening the D acutator topped out
between 17100 and 17900.  Later in the night, the limit was exceeded.
I suspect the thing that pushed it over the edge was the piston of
the secondary associated with scale factor being different from 1.0
during observing.
    If the secondary doesn't hit a limit with the scale set to 1.0, it
should never be an issue during imaging (baring some extreme
temperature possibly causing secondary piston to get large enough).
    It appears that a moderately large positive scale factor  (
~1.00025 or more ) is what is needed for the SecDesMountOutOfRange
error near zenith.  The only time I see this potentially causing
trouble is for spectroscopy when the scale factor is really large (
say 1.00050 or so ).  The secondary could conceivably run into a
limit below 80 degrees elevation in this case.  We should just keep
an eye out for this when the scale factor is large and positive.
    Since much of the time there is no problem at all, and even when
it does occur, it happens for altitudes outside of normal observing,
and only for spectroscopy (with the large scale caveat mentioned
above), I think the cage adjustment can wait until the bright time.
				Cheers,
				  Dan