Subject: cloud camera data analysis

From: richmond@astro.Princeton.EDU

Submitted: Thu, 27 Mar 1997 15:11:44 -0500 (EST)

Message number: 3 (previous: 2, next: 4 up: Index)

  I applaud the efforts of Gordon and Eric to combine information
from the MT and the IR camera, but I think it's harder than it seems.

  First, I have no script to parse APO night logs; I read the log file
by eye, and type by hand the information I want to keep into another file.

  Second, when someone runs the MT pipeline to reduce a set of MT images
into a photometric solution, he may or may not specify that the solution
be a function of time.  That is, he may make one solution covering
the entire night (in which case there will be a single extinction
value in each bandpass), or he may make, for example, three solutions
during the night (thus yielding three values for the extinction in
each bandpass).  The person may also flag explicitly certain times
from the night as "Good" and others as "Bad".  In most cases, I think,
the MT pipeline will yield 1-5 measurements of extinction per night
in each bandpass.

  However, no one yet has the job of reducing MT data on a regular
basis.  I have been trying to reduce a fair number of nights, just to
test the MT pipeline, but you can't count on me to do this.

  Third, it often (always?) happens that images from the cloud camera
are copied into a disk area on the MT computer in the morning, from
which they are copied to tape.  Those tapes are sent to FNAL.  Thus,
raw cloud camera images are sent with raw MT images to FNAL on a 
regular basis.  However, I believe that no one at FNAL currently
looks at the cloud camera images, nor is there any software at FNAL
to reduce the cloud camera images to a small set of statistics.
Both the software, and the manpower, would have to be provided
to the FNAL group in charge of regular data reduction.

  It would appear to me that this not a trivial task; just setting
up all the software to reduce cloud camera images at FNAL could take
a week or two (if we make it an SDSS product with cut versions
and documentation).  Writing a script to grab APO night logs via
FTP, then parse them to grab the required weather numbers, would
take a day or two ... and could be rendered useless if the format
of the APO night logs changes.  And, of course, there must be someone
at FNAL whose job it is to reduce MT (and cloud camera, and night log)
information daily.

                                     Michael Richmond
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