Theli-Forum

I've found a bug in CFH12K@CFHT99 split processing

Upps

Thomas

Camera 4 ist mirrored. Perhaps a header problem.

hi oleg,

that is not necessarily a bug, depending on whether the astrometric solution in the header matches the field orientation or not.

i don't have such images at hand. am i correct that the chip in question is number 1?

in that case, you could edit process_split_CFH12K@CFHT99.sh, locate the line saying
-M11 "-1,-1,-1,-1,-1,-1,-1,-1,1,-1,-1,-1"

and change -1 to +1 for the first element, i.e.

-M11 "1,-1,-1,-1..."

however, i am afraid that this might screw up the reference pixels and other stuff.
i have never worked with data from that instrument and just adopted the configurations from other people.
the CCD and header configurations of CFH12K changed about a dozen of times during its history, so you are in for a lot of trouble.

if you have problems with astrometry, i suggest you run scamp first with "mosaic_type = loose" until you have a good solution. once that is done, "update header", re-create the catalogs, and try with the normal scamp mosaic configuration.

mischa

mischa hat geschrieben:hi oleg,

that is not necessarily a bug, depending on whether the astrometric solution in the header matches the field orientation or not.

i don't have such images at hand. am i correct that the chip in question is number 1?

Yes, I've problem with first chip.

oleg hat geschrieben:

mischa hat geschrieben:Yes, I've problem with first chip.

so, does my suggestion concerning editing the splitting script work?

mischa

I've edited the process_split_CFH12K@CFHT99.sh according to your suggestion.

See the results:

Hi Oleg,
da nun Chip 9 auch falsch gespiegelt ist, würde ich die Toleranz für die Astrometrie erhöhen.
because of Chip No 9 being mirrored too, I would raise the position max err in astrometry.

not really sure.
Ciao
Carsten