Summary:
1) Is PHOTOM:PHOTGREY deprecated, and if so, why is it still described
in SUN/45?
2) PHOTGREY and PHOTOM produce SGS_ZONE errors.
3) PHOTGREY plus PHOTOM have a co-ordinate mismatch if the origin isn't
1,1.
Background:
A user reported a problem trying to make PHOTOM use his `sky'
co-ordinates (in fact pixel co-ordinates) but was using the grid
co-ordinates instead. I was unable to reproduce this with AUTOPHOTOM,
and asked what he did (twice). While not getting the detailed
steps, I learnt that he used PHOTGREY and manual PHOTOM.
When I tried this (all on RH9 with a summer /stardev from August 2).
rlsul1.bnsc.rl.ac.uk> photgrey
IN - Input image /@test/ >
Array dimensions are 1026, 1026
XSTART - First X index of subarray /1/ >
XEND - Second X index of subarray /1026/ >
YSTART - First Y index of subarray /1/ >
YEND - Second Y index of subarray /1026/ >
LOW - Lowest data value to plot /45.00816/ > 60
HIGH - Highest data value to plot /15620.64/ > 2000
DEVICE - Display device /@xwindows/ >
Scaling image
Plotting image
!! SGS_ZONE - New zone not inside current
! SGS_ZONE - Unable to create new zone
the zone rounding bug seemed to be present. The image displayed and
PHOTOM -> Measure reported in *grid* co-ordinates. I had to place the
cursor some 50 odd pixels to the lower right of the star to measure it.
Placing the cursor on the star image you get some weak background
signal. I'm unsure if this is what the user saw, but it looks like a
bug to me. Now I thought PHOTGREY was deprecated, so it can be ignored.
However, it's clear that it's not obvious to the users that they should
use KAPPA:DISPLAY+PHOTOM or the GAIA photometry toolbox. Then it's a
documentation bug.
On exit, PHOTOM gave SGS_ZONE errors.
COMMAND - PHOTOM /'Values'/ > exit
!! SGS_ZONE - New zone not inside current
! SGS_ZONE - Unable to create new zone
! SGS_SELZ - Invalid zone ID
! SGS_SELZ - Invalid zone ID
As an experiment I tried KAPPA:DISPLAY and PHOTOM. There are no
SGS_ZONE errors reported by DISPLAY, but PHOTOM reports some (one fewer
than before).
!! SGS_ZONE - New zone not inside current
! SGS_ZONE - Unable to create new zone
! SGS_SELZ - Invalid zone ID
The co-ordinates of the centroided star measured have the origin
applied, i.e. are pixel co-ordinates.
The AGI database trace is below.
rlsul1.bnsc.rl.ac.uk> hdstrace ~/agi_rlsul1.AGI_3800_1 full
DATABASE.AGI_3800_1 <WORKSTATION>
HEADER <_INTEGER> 9
PICTURE(4) <PICTURE> {array of structures}
Contents of PICTURE(1)
PNAME <_CHAR*15> 'BASE'
COMENT <_CHAR*12> 'Base picture'
DEVICE(4) <_REAL> 0,768,0,512
NDC(4) <_REAL> 0,1,0,0.6666666
WORLD(4) <_REAL> 0,1.5,0,1
MEMID <_INTEGER> 0
Contents of PICTURE(2)
PNAME <_CHAR*15> 'FRAME'
COMENT <_CHAR*8> 'PHOTGREY'
DEVICE(4) <_REAL> 0,768,0,512
NDC(4) <_REAL> 0,1,0,0.6658466
WORLD(4) <_REAL> 0,1.5,0,1
MEMID <_INTEGER> 0
Contents of PICTURE(3)
PNAME <_CHAR*15> 'DATA'
COMENT <_CHAR*8> 'PHOTGREY'
DEVICE(4) <_REAL> 128.3149,639.6851,0,512
NDC(4) <_REAL> 0.1670767,0.8329233,0,0.6658466
WORLD(4) <_REAL> 0,1026,0,1026
MEMID <_INTEGER> 0
Contents of PICTURE(4)
PNAME <_CHAR*15> 'DATA'
COMENT <_CHAR*13> 'KAPPA_DISPLAY'
DEVICE(4) <_REAL> 128.1478,638.8522,0.07485352,510.2966
NDC(4) <_REAL> 0.1670767,0.8329234,9.7656251E-5,
0.665749
WORLD(4) <_REAL> 40,1066,-44,982
MEMID <_INTEGER> 0
REFERENCE <_CHAR*14> '/home/mjc/test'
MORE <MORE> {structure}
AST_PLOT <WCS> {structure}
DATA(416) <_CHAR*32> ' Begin Plot',' Nframe = 12',
... ' ...',' Yb2 = 982',' End Plot'
PACTIVE <_INTEGER> 2
LABELS(4) <_CHAR*15> ' ',' ',' ',' '
End of Trace.
Does anyone understand the PHOTGREY co-ordinates and why we still have
AGItation in PHOTOM? I thought we applied fuzzy borders to bounds
checking.
Malcolm
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