Thursday, August 21, 2008

Clearing AIPS Variables?

During my recent forays into AIPS scripting, I have often wanted to change how a variable is defined...say by changing an array from dimensions of 50 to 200. When I try to do this, AIPS tells me that the variable is 'ALREADY DF' (or defined, i'm guessing). Is there some way to clear a variable?

Well, I just thought to do a 'RESTORE 0', which seems to clear everything. So maybe that it is the best solution?

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Sunday, August 17, 2008

MSGSRV Aesthetics

I've been wanting a scrollbar in my MSGSRV for as long as I can remember, and I finally got one! This is how I did it (on my Mac, running X11)...

I made a .Xdefaults file in my home directory with these lines:

AIPSmsg*scrollBar: True
AIPSmsg*saveLines: 500

I quit out of AIPS and in the xterm where I was running aips, I typed:

xrdb -load ~/.Xdefaults

to make my computer register the .Xdefaults file.

When I started up AIPS again, I had a scroll bar! This page gave me this hint, plus tells you how to change other MSGSRV settings, like colors.

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Thursday, August 14, 2008

Reading ASCII Tables into AIPS?

I'm trying to write a script where I repeat some steps on lots of different objects, and therefore I want to read a list of coordinates into AIPS. I currently have an ASCII list of x and y values. Can i read it into AIPS as two arrays so that my script can access them? Or do I have to do something hideous like manually fill the arrays within my script?

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AIPS system temperatures.. in miriad?

So we're trying to reduce our data in AIPS and then image in it miriad. Sounds familiar. Anyway, we want to use options=systemp when inverting the uv data. However, I've noticed that miriad doesn't appear to correctly import the system temperatuers from AIPS when using "fits" to read in the fits file that I wrote with AIPS using FITTP. In fact, it sets all the system temperatures to 60K, exactly.

There is an option in fits (varwt) to use the reciprocal of the noise variance on a visibility as its weight, but the system temperatures are still set to 60K.


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Monday, August 11, 2008

Mosaicing: AIPS/Miriad/whatever works!

Is anyone familiar with mosacing techniques in AIPS, Miriad, or both? I have 21cm VLA spectral line data, taken mosaic-style, and am having a heck of a time trying to stitch the pointings together. Here's what I have done so far:

Reduced in the standard manner with AIPS up until the 'SPLIT' step
Wrote out each pointing with FITTP
Loaded into Miriad
In Miriad, 'invert', 'mossdi', and 'restor', mostly with the defaults for parameters

The best way I can describe the results is like a bad patchwork quilt...does anyone know of a good cookbook or guide for putting together pointings into a mosaic? I know AIPS has some tasks for this (VTESS/UTESS/LTESS) but I haven't had success with them. Thanks!


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