Setting Up Astrometry

1. Setting up astrometry parameters

Astrometry parameters are listed in this table in section Astrometry.
Here are some prectical advices about setting up astrometry in daq ( and monte carlo simulation as well )

in order to enable / disable usage of asas-astrometry transformation use parameter :
CCD_USE_ASAS_TRANSFORM=1
in case you set it to 0 coordinates will be determined with respect to frame center coordinates and
geometric formuales which are very inaccurate due to non-linearities
enabling / disabling astrometry :
CCD_DO_ASAS_PHOT_ASTR=1
setting this parameter to 0 will disable astrometry, this can be done in case astrometry is correct in FITS headers
and you want offline analysis to depend on it without any time consumin tries of performing astrometry
all further parameter refer to situation when this one is set to 1 , otherwise no astrometry will occure
to specify timeout of astrometry on single frame set :
CCD_ASAS_ASTROMETRY_TIMEOUT=360
this will set timeout to 360 seconds , after this time not convered astrometry will be canceled.
to specific minimum number of stars identified by photometry to perform astrometry set :
CCD_MIN_STAR_COUNT_TO_RUN_ASTRO=5000
in order to force astrometry on first coming frame set :
CCD_DO_ASAS_ASTRO_ON_STARTUP=1
in order to require astrometry to be performed every N frame set :
CCD_AUTO_ASTROMETRY_FREQ=250
if <0 astrometry will be performed according to time interval specified by parameter :
CCD_AUTO_ASTROMETRY_FREQ_IN_SEC=1800
this two go together always minimum interval is choosen
parameter :
CCD_ASAS_ASTROMETRY_RETRY=5
specifies number of frames taken to retry astrometry if failed
parameter :
CCD_ASTROMETRY_SYNCHRO_MODE=1
specifies type of astrometry execution, wheather it is performed in synchronous mode , which means frames is taken and astrometry performed or
it can be done is such a way that astrometry is performed in second thread and in case passed updates current setting before next frame
is taken
in asynchronous astrometry mode sometimes normal-synchro version is called (for example after position change ) , but in case failed
number of synchro retries is speicifed by parameter :
CCD_FORCE_SYNCHRO_MAX_COUNT=2
after this number of failed astrometries asyncho version will be used again
parameter :
      CCD_ASAS_REVERSE_FOR_TRANSFORM=2
specifies if image must be fliped and how it must be fliped to be in agreement with star catalog orientation. There are following values possible :
       0 - no flip
       1 - full flip (0,0) -> (2062,2048)
       2 - horizontal flip x -> 2062 -x
       3 - vertical y -> 2048 -y
there are some parameter specific for off-line analysis of collected frames. Astrometry is saved in fits header and can be used off-line without
a need of performing it again for frames which have it. This parameters controll this :
CCD_USE_ASAS_ASTROMETRY_FROM_FITS=1
in case set to 1 astrometry is read from file, but note in case CCD_DO_ASAS_PHOT_ASTR=1 astrometry will still be performed in spcified
intervals or whenever coordinates change is detected.
In order to use fits coordinates in off-line analysis set :
CCD_USE_COORD_FROM_FITS=1

CCD_ASAS_ASTROMETRY_VERB=1

CCD_ASAS_ASTROMETRY_TRY=5

CCD_ASAS_STAR_CAT=$(DATADIR)/cat/act

PIXSCALE=59.5

CCD_ASAS_ASTROMETRY_FI=0

CCD_ASAS_BORDER_SIZE=0

CCD_ASAS_SUBTR_DARK=0

MAX_AST_ERR=0.1

MAX_AST_ERR_FATAL=0.2

2. Adding / updating astrometry section in fits files :

In order to re-run astrometry on all files listed in file frames_list run :

do_astro_all! frmes_list

and in case it is nessesary to update only fits files in some time interval ( let's say 5 minutes = 300 sec ) , run ;

do_astro_all_skip! frmes_list - 300

3. Make sure data is correct

Old data can be not complete , verify the following things :

value of FLIP key in FITS header, if it is not 2 - adding astrometry will fail
value of flip parameter in ccd.cfg file should be :
CCD_ASAS_REVERSE_FOR_TRANSFORM=2
check value of parameter CCD_OBS_MODE, it should be equal to 1 so does OBSMODE key in FITS header ( when mount was tracking ! )