Re: Progress as Usual

[Chris Albertson <calbertson@logicon.com>]

Tom Droege wrote:
> 
> I have been working away beating down the little nits that are so
> bothersome.  The new camera spacer rings came in today, and I am gluing up
> one as I type.  We shall see if this does not hold a better vacuum.
> 
> I think I am committed to the dry gas flow.  It works if I do not leave the
> cameras in the wet too long without gas flow.  Last night's run had a few
> ice crystals on the I camera because I turned it on too fast.  It looks
> like I need to run the dry air at a two bubble per second rate for about 4
> hours if I don't want to see ice.  I suppose it depends on how wet the air
> is.  The last few days we have had a lot of rain.
> 
> I called Lockheed today to see when the next 10 CCD chips will be
> shipped.  Jim Johnson (He is the "new" (old) guy in charge now.  He has
> been called back from retirement to get things moving.) asked why I needed
> taped on covers.  I said because of the ice problem and that I had seen ice
> on the "sealed" chips.  It turns out that the early "sealed" chips I have
> are probably not sealed.  For a sealed chip, there is a tube coming out the
> back.  So I am waiting on a drawing to see if I can drill a hole to
> accommodate the sealing tube.
> 
> A sealed dry CCD would solve most of the ice problem.  I would still want
> to circulate dry air though to prevent frost on the cover and filter.
> 
> I now have about 40 CCD ROMs of data with about the same properties as that
> on Data Disk 15.  This should produce 20 or so measurements in two filters
> on 100,000 stars over about 480 square degrees of sky.  I think this data
> would about double the tenxcat.  It might be worth reducing this data.  I
> have been mostly taking it to figure out the problems of day to day
> operation.  It is not so bad.  Does anyone want to grab this data and
> reduce it to a catalog?  It looks like Jure has worked through what it
> would take.  If someone wants to work up the software, I will process the
> disks through if it is something that is possible for me.  Or I will just
> send out the disks.
> 
> I think the data will get better, but not a lot better.  So this data might
> be worth processing.  OK, it does not have the good things that Jure has
> suggested in the .fts headers, so it will be a non-standard data set.

Fixing up the FITS header is no big deal even if there are 1000 files to
be fixed up.  There are a couple programs around that can apply a set of
changes to an entre directory of files.  

On my to do list is to verify that my Mk IV real-time program writes out
FITS headers as per Jure's suggestion.  I think it does.

One thing I thought of that I'll ssuggest we concider:  I seems that we all
want to keep the raw image data, Tom is keeping it just as it came off
the camera and Arne has suggested after 10X compression.  After reading
Jures tech note I thinkg we should at least modify the header to include
corrected WCS (ra, dec, image scale and rotation and maybe more) before
the data is archived.
> 
> Tom Droege

-- 
  Chris Albertson

  calbertson@logicon.com                  Voice: 626-351-0089  x17
  Logicon, Pasadena California            Fax:   626-351-0699