Download ORAC-DR – imaging data reduction

59
BRIGHT_POINT_SOURCE_NCOLOUR_APHOT
SUN/232.8 —Recipes
• For each cycle of jittered frames, the recipe creates a mosaic, which is then added into
a master mosaic of improving signal to noise. The exposure time is also summed
and stored in the mosaic’s corresponding header. Likewise the end airmass and end
UT headers areupdated to match that of the last-observed frame contributing to the
mosaic.
• The photometry tabulation includes the file name, source name, time, filter, airmass, the catalogue magnitude and estimates of the zero-point with and without the
application of a mean extinction. There are headings at the top of each column.
• The photometry uses the mode calculated from 3*median-2*mean and Chauvenet’s
rejection criterion to estimate the sky level in an annulus about the source. The inner
annulus diameter is 1.3 times that of the aperture (6.5 arcsec); the outer annulus is
2.5 times (12.5 arcsec) for UFTI, and twice the aperture (10 arcsec) for IRCAM and
Michelle.
The errors are internal, based on the sky noise.
• Intermediate frames are deleted except for the flat-fielded (_ff suffix) frames.
• Sub-arrays are supported.
Output Data :
• The resultant mosaic in <m><date>_<group_number>_<filter>_mos, where <m>
is the instrument’s group prefix.
• The individual flat-fielded frames in <i><date>_<obs_number>_ff, where <i>
is the frame prefix. The naming format is slightly different for some non-UKIRT
instruments.
• Results tabulation to $ORAC_DATA_OUT/aphot_results.txt.
Parameters:
NUMBER = INTEGER
The number of frames in the jitter pattern. If this is not set, the number of offsets,
as given by FITS header NOFFSETS, minus one is used. If neither is available, 5 is
the default. An error state arises if the number of jittered frames is fewer than 3. For
observations prior to the availability of full ORAC, header NOFFSETS will be absent.
[]
USEVAR = LOGICAL
Whether or not to create and propagate variance arrays. [0]
Related Recipes :
BRIGHT_POINT_SOURCE, BRIGHT_POINT_SOURCE_APHOT,
JITTER_SELF_FLAT, SKY_FLAT, SKY_FLAT_MASKED.
Implementation Status:
• The processing engines are from the Starlink packages: CCDPACK, KAPPA, and
FIGARO.
• Uses the Starlink NDF format.