From: [email-masked]
Date: Sun, 29 Oct 89 15:30:45 EST

>From Bob Wilson, AT&T Bell laboratories

To Dishfits community

Subject: Answers to questions in July 26 letter.

I will not be able to attend the conference, so let me reply to the questions.

1. What calibration/reduction/analysis software do you currently have?

	We use 'comb' (short for combine)  for handling spectral line
	data from the telescope.  It has all of the usual functions
	such as baseline removal, Gaussian fits to lines, etc.  It has
	a well developed macro and do loop system and with a few lines
	of command, all of the data in a given area of the sky from raw
	data files can be put in a 'stacks' file.  At that point,
	images can be made as either space-space maps of any reasonable
	parameter, or space-velocity maps.  These are displayed as
	contour maps and can be written as FITS files.  Images on a regular
	grid can be derived from irregularly sampled data.  Data in the
	'stacks' files are normally retrieved by position (and perhaps
	frequency) rather than stack numbers.

	We usually display the images from comb on our Sun workstations
	using a quick look or movie program.  We use grey scale for single
	images or independent rgb colors when looking at three different
	spectral ranges.  The latter works best with a 24-bit frame buffer
	on one of our Sun's, but can be simulated on the other 8-bit
	workstations using dithering.

	We have IRAF running and use it for most complicated image
	manipulating tasks since we haven't had a working version of
	AIPS since replacing our VAX with the Sun system.  Comb is
	able to make scatter plots and 1-D cuts across an image.

2.  How is your software effort organized in-house?

	Our telescope is on site and a daemon on the Sun file server
	transfers observations over a 9.6Kb/s line to data files on its
	disk as they are taken.  The telescope operation is quite automatic
	and we often monitor progress from our office or home.

	We import data from other observatories (30-meter, SEST, Pom2,
	12-meter, and Nobeyama come to mind).  In each case a special
	purpose program transforms the data to one of comb's formats.

	I am the chief programmer of both OBS and comb.  Marc Pound has
	done a lot with the display programs for the Sun's and John
	Bally has written many of the data translation programs.

3.  How do you support your users?

	We don't have a large stream of visiting observers.  We often
	run the observations for them as that is easier than explaining
	how to do it.  We invite them to come and analyze the incoming data
	after a large enough image is built up.

	Comb is running at several other sites on VAX with BSD style Unix, Sun,
	and HP-UX.

4.  What do you see as logical upgrade paths for:

   A. Hardware
	We work entirely in a UNIX environment (Suns right now) for
	data reduction and we are re-writing OBS for the Lynx operating
	system (a 'real time unix') using an AT buss 80386 machine.
	I think that comb could be ported to almost any Unix machine
	with little effort, but the data presentation programs are
	particular to Sunview. and may have to be re-written (for X-windows?)
	in the future when our hardware changes.

   B. Software
	We put multiple spectrometers in a single 'scan' in our raw data file,
	but treat each as a separate observation in the 'stacks' files.
	I haven't faced up to multiple feeds, since we don't have them yet.

5.  How do you view the prospect of shared code for common use at multiple
observatories?

	I think that the past practice of each observatory writing its
	own code completely is a silly waste of effort.  Does anyone have
	an organized set of routines for pointing, etc.?  I have been trying to
	talk the U.S.Naval Observatory out of some of their code.  Peter
	Stumpf's 'BARVEL' of 10 years ago saved me a lot of effort.

	I would be happy to share any of our data reduction programs with
	anyone wanting to use them.  When the new OBS is completed, we will
	be using it with AST/RO and I would be happy to share it.

6.  Could single-dish work make better use of AIPS/IRAF/other packages not
specifically targeted for it?

	Yes.  We have been doing that for several years and it has been
	very effective.

Robert W. Wilson
[email-masked]
201-888-7120