D Recipes

 D.1 Classified Recipes
 D.2 Reference documentation

The original set of recipes and names were prescribed in G.S. Wright & S.K. Leggett, 1997, Scripts for UFTI, orac009-ufts, v01.

D.1 Classified Recipes

In hindsight you may decide that there was a better recipe for your data than stored in the RECIPE header. Also you may have used a faster variant of a recipe at the telescope, but now want the full reduction. Here is a classified list so that you can select an alternative. Magnitudes and dimensions apply to UFTI, except for the NOD_SELF_FLAT_NO_MASK recipes, whose magnitude ranges are for IRCAM; and the *NOD_CHOP* recipes which are applicable to Michelle. For IRCAM, dimensions are 10% smaller; for IRIS2 dimensions are 6.8× larger; for UIST they are either 33% smaller or 22% larger depending on the camera. The magnitude ranges are courtesy of Sandy Leggett and apply to UKIRT.

Calibration Recipes



Recipe Name

Type of Data

Function and Comments




ARRAY_TESTS

Array check

Calculates read noise and dark current.




DARK_AND_BPM

Dark and Mask

Measures dark current and creates a new bad-pixel mask for UIST.




DIFFERENCE_STATS

Array Check and Mask

Calculates statisticd for Michelle darks in a pairwise manner.




LAMP_FLAT

Mask

Creates and files imaging flat fields derived from a calibration lamp for ESO instruments.




MAKE_BPM

Mask

Creates a bad-pixel mask by standard-deviation thresholding.




MEASURE_READNOISE

Array check

Measures and files the readnoise for UIST from a set of dark frames.




REDUCE_DARK

Dark

Averages and files observations as the current dark.




REDUCE_FLAT

Flat

Reduces an imaging flat field.




SKY_FLAT

Flat

Creates and files a flat field derived from five jittered frames. Mostly for use with BRIGHT_POINT_SOURCE recipes. Requires a dark.




SKY_FLAT_FP

Flat

Creates a Fabry-Perot sky flat (from jittered blank-sky exposures) FP at on- and off-line wavelengths. Requires a dark.




SKY_FLAT_MASKED

Flat

As SKY_FLAT but masks objects to give a better flat field.




SKY_FLAT_POL

Flat

Obtain a ‘master’ polarimetry flat field from the median average of eight jittered frames; the waveplate is cycled after every second frame. Makes a copy of the flat for each waveplate angle. Requires a dark.




SKY_FLAT_POL_ANGLE

Flat

Obtain four polarimetry flat fields, one for each waveplate angle, from the median average of jittered frames. Requires a dark.




Miscellaneous recipes



Recipe Name

Type of Data

Function and Comments




ADDWCS

Creates the valid WCS in the FITS headers of raw data.




NIGHT_LOG

Generates a text-file log of a series of observations.




Very-bright-point-source recipes



Recipe Name

Type of Data

Function and Comments




BRIGHT_POINT_SOURCE

IZ < 13, JHK < 9, and bright 13 < IZ < 17, 9 < JHK < 15

Normally a 5-point jitter but would be usable as 3-point. Requires a separate flat as the background is too low to self flat, and a dark.




BRIGHT_POINT_SOURCE_APHOT

As BRIGHT_POINT_SOURCE, but also performs aperture photometry of the source.




BRIGHT_POINT_SOURCE_NCOLOUR

As BRIGHT_POINT_SOURCE, but produces filenames that include filters for easier identification for multi-colour observations.




BRIGHT_POINT_SOURCE_NCOLOUR_APHOT

As BRIGHT_POINT_SOURCE_APHOT, but produces filenames that include filters for easier identification for multi-colour observations.




BRIGHT_POINT_SOURCE_TELE

As BRIGHT_POINT_SOURCE, but uses telescope offsets for registration.




BRIGHT_POINT_SOURCE_TELE_APHOT

As BRIGHT_POINT_SOURCE_APHOT, but uses telescope offsets for registration.




Point-source recipes—thermal



Recipe Name

Type of Data

Function and Comments




NOD_SELF_FLAT_NO_MASK

Bright L < 10; or all M, faint L > 10

Nod jitter, self flats of differenced pairs of frames. Has superior and fast sky subtraction. No object masking. Requires a dark. Use 4-point jitter for L < 10, and 8-point for fainter L and all M.




NOD_SELF_FLAT_NO_MASK_APHOT

As the previous recipe, but also performs aperture photometry of the positive and negative sources.




NOD_SKY_FLAT_THERMAL

Nod jitter, interspersed sky frames. Sky subtraction, flat field created from sky frames only. Requires a dark. 4-point jitter (8-point sequence).




Bright-point-source recipes



Recipe Name

Type of Data

Function and Comments




JITTER_SELF_FLAT

13 < I,Z < 17, 9 < JHK < 15

Standard jitter, self flats. Normally 5-point jitter. Requires a dark.




JITTER_SELF_FLAT_APHOT

As JITTER_SELF_FLAT, but also performs aperture photometry of the source.




JITTER_SELF_FLAT_NO_MASK

As JITTER_SELF_FLAT but faster as it lacks object masking. It only suitable for uncrowded fields.




JITTER_SELF_FLAT_NCOLOUR_APHOT

As JITTER_SELF_FLAT_APHOT, but produces filenames that include filters for easier identification for multi-colour observation sequences.




SKY_AND_JITTER

A sky frame and jitter on target. The sky is subtracted from the target frame before flat fielding. Requires a separate flat, as the background is too low to self flat, and a dark. No longer recommended as sky varies too quickly.




SKY_AND_JITTER_APHOT

As SKY_AND_JITTER, but also performs aperture photometry of the source.




Faint-point-source recipes



Recipe Name

Type of Data

Function and Comments




JITTER_SELF_FLAT

Faint I,Z > 17, JHK > 15

Standard jitter, self flats. Normally 9-point jitter. Requires a dark.




JITTER_SELF_FLAT_CATALOGUE

As JITTER_SELF_FLAT but produces an inventory of the locations and brightnesses of sources within the mosaic.




BRIGHT_POINT_SOURCE_CATALOGUE

As BRIGHT_POINT_SOURCE but produces an inventory of the locations and brightnesses of sources within the mosaic. Preferred when a self-flat is not appropriate.




JITTER_SELF_FLAT_BASIC

Fastest JITTER_SELF_FLAT recipe as it lacks object masking, automatic registration and resampling.




JITTER_SELF_FLAT_NO_MASK

As JITTER_SELF_FLAT, but faster as it lacks object masking. It only suitable for uncrowded fields.




Extended-source recipes



Recipe Name

Type of Data

Function and Comments




QUADRANT_JITTER

Galaxies, quasars and nebulae of small ( <45 arcsec) angular extent

4-point jitter; masks the quadrant containing the target to make the flat, then masks the objects. Requires a dark.




QUADRANT_JITTER_NO_MASK

As QUADRANT_JITTER but without object masking.




QUADRANT_JITTER_BASIC

Fastest QUADRANT_JITTER variant as it lacks object masking, automatic registration and resampling.




MOVING_QUADRANT_JITTER

Compact comets ( <45 arcsec)

As QUADRANT_JITTER, but uses ephemeris data to track the non-sidereal source.




QUADRANT_JITTER_TELE

As QUADRANT_JITTER but uses telescope offsets for registration. Telescope tracks object.




EXTENDED_3x3

Galaxies and nebulae with angular extent <2 arcminutes

Sky-subtracted 3×3 grid mosaic on target. Frames alternate between sky and target. Requires a dark.




EXTENDED_3x3_BASIC

As EXTENDED_3x3 but lacks resampling and registers using telescope offsets.




EXTENDED_5x5

Galaxies and nebulae with angular extent <3 arcminutes

Sky-subtracted 5×5 grid mosaic of the target. Frames alternate between sky and target. Requires a dark.




EXTENDED_5x5_BASIC

As EXTENDED_5x5 but lacks resampling and registers using telescope offsets.




Point-source recipes—mid-infra-red



Recipe Name

Type of Data

Function and Comments




NOD_CHOP

Bright N and Q (limits to be determined)

Chopped and nodded observations to remove sky background and telescope contributions; differences both chopped beams and nodded pairs of frames giving a mosaic with two positive and two negative images. There is no masking or flat-fielding. Requires a bias in CHOP mode, e.g. from recipe ARRAY_TESTS.




NOD_CHOP_APHOT

As the previous recipe, but also performs aperture photometry of the combined four images (after extraction and centroid registration).




NOD_CHOP_FAINT

As NOD_CHOP, but removes column and row artifacts from the mosaic, then it combines each chopped and nodded image using a median filter to form an image of the source with four times the signal. This image is then smoothed to enhance the visibility of faint sources.




NOD_CHOP_SCAN

As NOD_CHOP, but for chopped and nodded observations that are taken in a scan pattern. A mosaic is formed at each scan position.




Moving (non-sidereal) source recipes



Recipe Name

Type of Data

Function and Comments




MOVING_JITTER_SELF_FLAT

Minor planets, comets

As JITTER_SELF_FLAT, but uses ephemeris data to track the non-sidereal source.




MOVING_JITTER_SELF_FLAT_BASIC

As JITTER_SELF_FLAT_BASIC, but uses ephemeris data to track the non-sidereal source.




JITTER_SELF_FLAT_TELE

Standard jitter, using telescope offsets. This is needed when the telescope has tracked on the non-sidereal target. Requires a dark.




MOVING_NOD_CHOP

As NOD_CHOP, but uses ephemeris data to track the non-sidereal source in the mid-infra-red.




MOVING_QUADRANT_JITTER

Compact comets

As QUADRANT_JITTER, but uses ephemeris data to track the non-sidereal source.




QUADRANT_JITTER_TELE

As QUADRANT_JITTER but uses telescope offsets for registration. This is needed when the telescope has tracked on the non-sidereal target.




Polarimetry recipes



Recipe Name

Type of Data

Function and Comments




POL_ANGLE_JITTER

Polarimetry of point or small ( < 35 arcsec) extended sources

Makes a polarisation map from frames at the four waveplate angles at each of at least three jittered positions; the waveplate is moved before the telescope. An appropriate dark and separate flat fields at each waveplate angle (using SKY_FLAT_POL or SKY_FLAT_POL_ANGLE) must be obtained.




POL_ANGLE_NOD_CHOP

Polarimetry of point or small ( < 10 arcsec) extended sources in mid-infra-red

Makes a polarisation map from chopped and nodded frames at the four waveplate angles at two nod positions; the waveplate is moved before the telescope is nodded. There is no object masking or flat fielding. Requires a bias in CHOP mode, e.g. from recipe ARRAY_TESTS.




POL_EXTENDED

Polarimetry of extended sources

Makes a polarisation map of an extended source from frames nodded between object and blank sky. The object-sky pairs must be taken at each of the four waveplate angles. Requires an appropriate dark and separate flat fields at each waveplate angle.




POL_JITTER

Polarimetry of point or small ( < 35 arcsec) extended sources

Makes a polarimetry map from frames at the four waveplate angles at each of at least three jittered positions; the telescope is moved before the waveplate. An appropriate dark and flat fields at each waveplate angle must be obtained.




POL_NOD_CHOP

Polarimetry of point or small ( < 10 arcsec) extended sources in mid-infra-red

As POL_ANGLE_NOD_CHOP but the telescope is nodded before the waveplate is moved.




POL_QU_FIRST_NOD_CHOP

Polarimetry of point or small ( < 10 arcsec) extended sources in mid-infra-red

It is a hybrid of POL_ANGLE_NOD_CHOP and POL_NOD_CHOP as the waveplate angle iterates in pairs at each jitter position.




SKY_FLAT_POL

Flat

Obtain a ‘master’ polarimetry flat field from the median average of eight jittered frames; the waveplate is cycled after every second frame. Makes a copy of the flat for each waveplate angle. Requires a dark.




Fabry-Perot recipes



Recipe Name

Type of Data

Function and Comments




FP

Fabry-Perot

Uses a sequence of eight frames; object-sky pairs at on-line, off-line (blue), on-line and off-line (red) FP settings to make a mosaic. Requires a separate flat field (made by SKY_FLAT_FP) and a dark.




FP_JITTER

On/Off-line images with nodding to blank sky (as FP), and spatial jittering on-source. Requires a separate flat field and a dark.




FP_JITTER_NO_SKY

On/Off-line images without nodding to blank sky (i.e. sequence of four frames), and spatial jittering on-source. Requires a separate flat field and a dark.




SKY_FLAT_FP

Flat

Creates a Fabry-Perot sky flat (from jittered blank-sky exposures) FP at on- and off-line wavelengths. Requires a dark.




D.2 Reference documentation

The following recipes apply to both UFTI and IRCAM unless otherwise noted. Where there are processing differences for the two instruments, they are noted in the reference specification. Also there is an ARRAY_TESTS recipe for each instrument, of which only UFTI’s is presented below for technical reasons.

In the Configurable Steering Parameters sections the defaults appear at the end of the parameter’s description between [ ].

The non-generic recipes of the original release are not documented here, but are still available for reducing pre-ORAC (2000 August) data. They are listed in the Deprecated variants section of their generic counterpart. Each behaves as the generic counterpart, except the number of jitter points is fixed. Thus the JITTER9_SELF_FLAT reduces a nine-point jitter.