Re: [TASS] photometric vs. non-photometric

[Andrew Bennett <andrew.bennett@NS.SYMPATICO.CA>]

On Fri, 3 Sep 1999 16:22:27 -0700, Chris Albertson
<calbertson@LOGICON.COM> wrote:

>If the star is in an area of the sky that was covered by the survey
>and it is not in the tass_catalog then it must have been below
>TASS' detection limit for any of a number of reasons.  To dim,
>to bright, to close to another star, bad luck with clouds, and
>so on.
>
>There is lots of raw data to look at.  I think it you asked you could
>get a reasonable sized sample.
Which, being interpreted into the vernacular means:
"Bennett - put up or shut up!"
Yes. This looks like something I could undertake to
fill up those long winter evenings ...

>  I would imagine that by now the total
>raw FITS image data is in the tens of gigabytes.
I have a more vivid imagination; umpteen tens of
gigabytes. I would propose to look at a VERY small
area. Or better, two very small areas.

How about RA 10-15 degrees (includes 1 TASS variable)
and RA 290-295 (high density, 5 TASS variables)?
Please make suggestions for different areas before
anybody burns any CDROMs!

I would propose to look at every star in the TASS
database in selected very small subareas, on every
image provided and attempt to build up statistics,
for those stars that don't appear in all cases, on why
they are not there.

I think this would tell us a lot about the reliable
magnitude limit for the Mk III and the information
should carry over (m.m.) to the Mk IV.

To do this, I would need:
1) Raw + Dark + Flat (preferably) or processed FITS
files for all processable images anybody is willing
to let me have that overlap my chosen analysis areas.
I am perfectly willing to accept somebody else's
decision that a particular image is not processable -
a few marginal ones would be of interest.
2) Information as to precisely where the image is on
the sky - I gather from previous posts that this may not
be written back to the processed FITS header and is
probably pretty rough in the raw FITS files. The last
time I tried to locate somebody else's image, the
software threw a tantrum ... announced you couldn't get
there from here and gave up.
3) Lots of help when I start finding what the real
problems are.

That's still a lot of data. I'll pay for CD's
and postage!

Andrew Bennett, Avondale Vineyard, Nova Scotia, Canada.