Re: [TASS] Martin's variable, FITS keywords, FAQ, etc.

[Tom Droege <droege@WWA.COM>]

For the last few days I have been running TOM and collecting data.  For
some reason, the sky is relatively clear.  La Nina, I guess.  OK we are
pretty near the longest night of the year, and last night's run filled 3 CD
ROMs.  The year I kept track, there was about 80 observing nights.  At 1.5
CDs average, this would be 120 CDs.  They should be less than $1 soon.

I think this is not much of an expense to save *all* the data.  At the
moment, I just run it through Ted's program to convert it to .fts and write
it out.  The biggest pain is the time it takes.  Eventually some utility
programs should make this easier.  Also, I am making a duplicate set so
that I can send the data out for analysis.  That would not be necessary in
the future.

Arne might spend a bit more, $500 or so for a year's run.  But worth it, I
think.

I figure I already have the equivalent of 10xcat on disk, at possibly 2 mag
greater sensitivity.

The plan is to use the data I am collecting now to develop the data
processing channel.  With any luck, and the continuation of La Nina, I
could get twice what I have now by year end.  Possibly 20 measurements in V
an I on 200,000 stars.   This should make a nice test sample.

The data is OK, but not great.  The I camera is noisy for some reason,
stars are not quite round, there are some ice crystals, but all in all, the
data is better that what I got from the Mark  III.

Tom Droege

At 08:25 AM 12/1/99 -0700, you wrote:
>Chris wrote regarding my suggestion that UT = start of exposure:
>>Why start-of-exposure? I would think mid exposure better
>>reflects when the oberservation was made.  Knowing the
>>exposure time you can always compute one from the other
>>so does it really matter?
>  The FITS standard for DATE-OBS (and therefore by implication
>UT) is for the start of observation.  This is also the convention
>used by all of the professional observatories at which I have
>observed.  It is also much easier for drift-scan data to have
>the UT refer to the first row of the image rather than the
>middle.
>
>Regarding engineering data carried forward in extraction files,
>Chris wrote:
>>I was thinking that as we intend to likely throw away the
>>image files we would want to carry the engineering data forward
>>in the derived files and database.
>I plan on keeping compressed versions of the image files.  Having
>a log file that you keep also archives the engineering data.  It
>has no use in starlists, so I don't see the need to add a page
>of voltages to every ascii starlist file.  The engineering stuff
>is useful for initial setup and tracing problems, but not in
>survey operation.
>
>Arne
>
>