[daip] flux not conserved in CONVL task

[Sayali Avachat]

To Whomsoever it may concern,

I am having some issues with the task CONVL.
I am trying to convolve optical maps (take from HST observations and
obtained using HST data reduction processes) to the resolution of VLA maps
at 15GHz.
It looks like CONVL does the job of converting the beam size and PA to that
of radio, but at the same time it does change the flux values of optical
image.
I tried using factor = (new beam)/(old beam), leaving opcode blank and
using radio map in In2name.

I am not sure what is happening here. I have started to get the feeling
that essentially being two different observations from two different
telescopes, AIPS is doing some weird things and it cannot read certain
header information in order to retain the flux of the original optical
image.

I manually PUTHEADed the beam size (0.06675x0.06675) in the map header
before I ran CONVL.

Below are the headers of optical image, before and after convolution.
BEFORE -
AIPS 1: Image=NONE      (MA)         Filename=M87F606W0505.IFLUX .   1
AIPS 1: Telescope=HST                Receiver=ACS
AIPS 1: Observer=                    User #= 1306
AIPS 1: Observ. date=09-MAY-2005     Map date=03-OCT-2013
AIPS 1: Minimum=-1.59414474E+02      Maximum= 3.76874359E+02 uJy
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: RA---TAN  2496    12 30 49.503    1248.00      -0.025000    0.00
AIPS 1: DEC--TAN  2464    12 23 29.124    1232.00       0.025000    0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 2000.00
AIPS 1: Map type=DIRTY               Number of iterations=       0
AIPS 1: Conv size= 0.06675 X 0.06675   Position angle=   0.00
AIPS 1: Maximum version number of extension files of type HI is   1
AIPS 1: Maximum version number of extension files of type ST is   1
AIPS 1: Maximum version number of extension files of type MF is   2

AFTER -
AIPS 1: Image=NONE      (MA)         Filename=M87F606W0505.ICONV .   1
AIPS 1: Telescope=HST                Receiver=ACS
AIPS 1: Observer=                    User #= 1306
AIPS 1: Observ. date=09-MAY-2005     Map date=10-OCT-2013
AIPS 1: Minimum=-5.96672314E+03      Maximum= 5.02040039E+02 uJy
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: RA---TAN  2496    12 30 49.503     776.19      -0.025000    0.00
AIPS 1: DEC--TAN  2464    12 23 29.124     434.84       0.025000    0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 2000.00
AIPS 1: Map type=DIRTY               Number of iterations=       0
AIPS 1: Conv size= 0.41771 X 0.39941   Position angle=  49.54
AIPS 1: Maximum version number of extension files of type HI is   1

Can someone please help me?

Thank you,

-- 
Sayali S Avachat
PhD Candidate
Department of Physics and Space Sciences
Florida Institute of Technology
savachat2008 at my.fit.edu
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