K Release Notes—V2.1-0

The main changes are the addition of spatially jittered Fabry-Perot recipes, and recipes for compact comets.

K.1 New recipes

FP_JITTER

Reduction of a Fabry-Perot observation, comprising eight frames, on and off the source, and on and off the spectral line both to the blue and to the red. This is repeated for a series of spatial positions of the source.

FP_JITTER_NO_SKY

Reduction of a Fabry-Perot observation, comprising four frames, all on the source, and on and off the spectral line both to the blue and to the red. This is repeated for a series of spatial positions of the source.

MOVING_QUADRANT_JITTER

As QUADRANT_JITTER but registration is adjusted to track the motion of a comet using ephemeris data. The comet should $<$45 arcsec diameter for UFTI, or $<$10 arcsec for IRCAM. Compared with MOVING_JITTER_SELF_FLAT, this recipe avoids cometary artifacts appearing in the flat field.

QUADRANT_JITTER_TELE

As QUADRANT_JITTER, but registers using the telescope offsets. This is used for observing compact comets (limiting angular sizes as above), when the telescope has tracked the nucleus.

K.2 Modified recipes

• ARRAY_TESTS For UFTI, the ADU conversion is obtained from the GAIN header, rather than being hardwired at 7.0.
• CHOP_SKY_JITTER This now functions correctly for multiple cycles of the recipe.
• FP Documentation improvements especially in the description. Primitive _FP_STEER_ has a new steering parameter, NPAIRS, and parameter NUMBER has changed to its normal meaning.
• NIGHT_LOG This can start from observation numbers other than 1. A bug has been fixed where the dimensions appeared as zero for UFTI. It arose because certain headers no longer existed after 2000 August.
• SKY_FLAT_FP This is no longer limited to eight frames.
• SKY_AND_JITTER A bug has been fixed where some intermediate files were not being removed for this recipe and its variant.

K.3 Global changes

The main changes from a user perspective were as follows.

• The aperture for _APHOT recipes is now 5 arcseconds.
• A new photometry catalogue fs2001.dat, supplied in original form by Sandy Leggett, is used by the _APHOT recipes. The new catalogue contains $IZLM$ magnitudes for the first time, and the $JHK$ data have been refined to account for recent observations. The 2000 edition is accessed for $JHK$ photometry if the 2001 catalogue is unavailable.
• Another new UFTI bad-pixel mask. Old masks are available on request.
• A bug that affected some rare mixed-method registrations has been fixed. The $y$ offset had the wrong sign.
• Allow for a special case in the mosaicking registration, when the nearest-neighbour method is used to align the various images, and an automatic multiple-object registration was found. It was possible not to find a common object identifier in all the fields when the target is a low-surface brightness galaxy. While this is still possible, it is far less likely than before.
• The IRCAM saturation level was refined upwards to 20000, or 33000 if header SPD_GAIN is "Deepwell". SPD_GAIN is created by the recipe when it is absent, based upon the value of the detector bias.
• The message concerning an AST SKY Frame creation, which could be confused with a data frame of blank sky, has been clarified. The same script allows for a missing CROTA2 header in old data when inserting world co-ordinate system headers.
• Various minor improvements and corrections to the documentation, such as correcting the former prefix for UFTI mosaics in the reference section, and excluding references to IRCAM in the FP recipes.