[fitsbits] FITS astrometry formats

[Walter Jaffe]

Gentlemen and ladies,

I have the privilege of initiating the design of FITS format applications
for astrometry usage for ESO's VLTI, with particular application
to the dual beam PRIMA system.

I would appreciate pointers from those of you with astrometry experience
to examples that I might learn from, either radio or optical/IR.

A little background:  PRIMA will be a dual beam, single baseline interferometer
operating mostly with the outrigger (1.8m) telescopes at Cerro Paranal at
K-band, with baselines to 200m.  Our long term goal is to get relative
astrometry over fields of 10" or so to 10 microarcsec accuracy.

In addition to scanned fringes in three sub-bands of the K-band
we hope to record metrology data from the whole delay train.  These
two data streams will be read at a few kHz.  We will also record
engineering data from all of the active optical subsistems at a
similar rate, and environmental data at a slower rate.  The recording
of each subsystem is generally asynchonous, but with a mountain-wide
master clock being repeated at each subsystem.

I want to store all this in FITS bintable formats, with the current IAU
standards (descended from the Jaffe/Cotton document) as a starting point.
In addition I want to store emphemerides, geodeitic information... that
has been used in the reduction.

Walter Jaffe