Re: [alma-sw-ssr] Offline Requirements v3.1

[mel wright 456 <wright@astron.berkeley.edu>]

Hello Steve, Robert,

	I've worked thro' the requirements a few
times. Looks complete, but I'd put more emphasis on 
efficiency and efficacy.  If the package only does
priority 1 - it could be very inconvenient and inefficient.
e.g.

1. combining multiple data sets.

OL-3.1-R14 -R15
OL-5.1-R2

2. bloat
OL-3.2-R4

are given low priority.

An analysis based on this document, could easily miss some
powerful features built into the low level
routines of the MIRIAD software which make it 
efficient and convenient for the astronomer.

1. A powerful data selection mechanism with Boolean combinations
----------------------------------------------------------------
e.g. these times and these antennes, and these times for those antennas.
e.g. this uv-range not shaddowed by more
than 10% and that uv-range not shaddowed by more than 50%
[I want to self-cal on the compact emission, and
to mosaic large scale structure.]

OL-4.1-R6 also applies to plotting and imaging.

2. On-the fly spectral re-binning. 
---------------------------------
. plot,  uv-data for these 10 velocity intervals for this spectral line.
 (amplitudes and/or phases, with or without the calibration
[gain, bandpass, polarization],applied).
. derive bandpass for averaged channels.
. image this spectral line in these 32 contiguous velocity intervals.

3. Bloat.
---------
OL-3.2-R4 is given low priority.

. when imaging a spectral line, the spectra can be processed
as a vector; much more efficient. (MIRIAD was 13x faster than aips
last time I tried) [1 day versus 2 weeks ?]. 

. only one beam per pointing is needed for most spectral imaging;
a huge saving in bloat. Sure, one can argue about precision, but
the final mosaiced image may only have 100:1 fidelity, and you
can always make one beam per channel if you want.

A large spectral line mosaic should be included in the test suite. 
 

Melvyn