id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
1014	Bad astrometry not flagged in database	Paul Price	eugene	"In running the Wainscoat MOPS survey through the IPP, I've found one image that produced two failed warpSkyfiles (exp_name = 905249p, exp_id = 109, chip_id = 110, cam_id = 108, warp_id = 108, skycell_id = skycell.026293[67]).  The images are weird, like it's been stretched.  Also, judging from the claimed overlap, I would expect to see more lit pixels.

It seems that the astrometric solution is bad.  I attempted an independent psastro run, with the following result:

2007-11-17 00:06:26Z|mithrandir          |I|psastro
    astrometry solution: error: 891.982971 arcsec, Nstars: 74
2007-11-17 00:06:27Z|mithrandir          |I|psastro
    residual error is too large, failed to find a solution: 891.982971 > 0.500000
2007-11-17 00:06:27Z|mithrandir          |I|psastro
    failed to find a solution for 35,0,0
 pmAstromFitDistortion (pmAstrometryDistortion.c:174) : Unallowable operation: psArray gradients or its data is NULL.
 psastroMosaicGradients (psastroMosaicGradients.c:87) : failed to fit the distortion terms
 psastroMosaicAstrom (psastroMosaicAstrom.c:74) : failed to measure mosaic gradients (2nd pass)
 psastroAnalysis (psastroAnalysis.c:60) : failed to perform mosaic camera astrometry
failure in psastro analysis
 
 -> pmAstromFitDistortion (pmAstrometryDistortion.c:174): parameter is null
     Unallowable operation: psArray gradients or its data is NULL.
 -> psastroMosaicGradients (psastroMosaicGradients.c:87): Unknown PM error code
     failed to fit the distortion terms
 -> psastroMosaicAstrom (psastroMosaicAstrom.c:74): Unknown PM error code
     failed to measure mosaic gradients (2nd pass)
 -> psastroAnalysis (psastroAnalysis.c:60): Unknown PM error code
     failed to perform mosaic camera astrometry
 

I then noticed that there really isn't a lot of stars visible in this image.  It turns out it's a 2 sec exposure.

Rerunning ppImage photometry and astrometry, I get ""failed to find a solution"" for the majority of the chips; from the log file:

[...]
2007-11-17 00:49:51Z|ipp002              |I|psastro
    insufficient stars (1) or invalid order (0)
2007-11-17 00:49:51Z|ipp002              |I|psastro
    failed to find a solution for 0,0,0
2007-11-17 00:49:51Z|ipp002              |4|psastro
    mosaic fit chip order 0
2007-11-17 00:49:51Z|ipp002              |I|psastro
    astrometry solution: error: 8.842741 arcsec, Nstars: 4
2007-11-17 00:49:51Z|ipp002              |I|psastro
    residual error is too large, failed to find a solution: 8.842741 > 0.200000
2007-11-17 00:49:51Z|ipp002              |I|psastro
    solution uses too few stars: 4 < 6
2007-11-17 00:49:51Z|ipp002              |I|psastro
[...]

Plotting the astrometry under dvo with 'imbox' produces shapes which aren't as square as I would expect.

Also, the residual error reported by psastro is different from that recorded in the .smf file:

price@ipp003:/data/ipp002.0/MOPS/run1/proc/905249p.109>echo 905249p.109.ch.110.smf | fields -n hdr NSTARS NASTRO CERROR
905249p.109.ch.110.smf[ccd00.hdr]  1066  9  0.2679958
[...]

So it looks like the astrometry is bad, but ppImage is succeeding, and the error status is not getting reported in the database."	enhancement	closed	normal		psastro	unspecified	minor	fixed