TASS Database, plans and progress.

[Chris Albertson <chris@topdog.pas1.logicon.com>]

Hello,

Here is the latest news about what I'm doing with database software.
I keep posting this stuff because it seems to attract mostly useful
comments.  And yes, I've keep making changes based on those comments
so it seems to be worth it.


Bad news:  I have to go to Killeen Texas for 10 days starting next week.
Good news:  I don't think I'll have much to do out there so I am bringing
a Pentium laptop with a Postgres Database server, sample data and 
associated software with me.  Should have plenty of time to get something
working.

I now have (as yet untested) code that splits the observation table up 
into multiple tables.
This is required to get around the 2GB per file limit imposed by most
32-Bit OSes.  The software first splits the data based by filter then into 
ranges of JD.  At the current rate of data collection each table can hold
about one year of data.  This had to be done as the current "everything in
one table" design would overflow to soon.

Version 1.0 goals are unchanged:
1) "seeded" catalog based on Arne's "tassm16" list. (mostly working)
2) Improved install procedure and packaging. (decent start)
3) Documentation.  (note lack of adjective like "complete" or 
   "well written") (a few words are written..)
4) ability to store and output calibrated photometry.  I'll
   supply a dummy procedure that computes a constant color
   transform.  Someone else (Arne?) can modify it so that it
   actually computes something  (not started yet)
5) Remove 2GB limit on total observations stored. (need to test)

Looks like I could have a Version 1.0(beta) in May (this year)

Notes:
1)  I've been convinced.  I'll go with common units throughout.
    positions and position errors are milliarcsecnods (mas).
    millimagnitudes for brightness.
2)  re. #4 above:  While it is normally not done this way,  I
    assume a color transformation can be written as

              V = a*v + b*r + c*i
              R = d*v + e*r + f*i
              I = g*v + h*r + i*i

   So for n colors you get an n by n matrix with a few zero terms.
   Each matrix will be tagged with a beginning and ending JD and
   site name where it is applicable.
3) The dummy calibration routine will accept the following as input
     a) An array containing all of the Landolt data.
     b) An array containing TASS observations of Landolt stars by one
        site over a defined period of JD (nominally one night)
   The routine will produce as output the above matrix.  My dummy
   routine will always write out 
   1  0  0
   0  1  0
   0  0  1

   Question: should anything else be computed, like for example a
   "degree of fit" or error number?  and if so does this need to be
   stored with the matrix? and then how is it later used?                   

              
-- 
--Chris Albertson

  chris@topdog.logicon.com                Voice:  626-351-0089  X127
  Logicon RDA, Pasadena California          Fax:  626-351-0699