• MOSAIC_JCMT_IMAGES

MOSAIC_JCMT_IMAGES

Description

Coadd the given files into a single map, taking into account the EXP_TIME and other NDF components. The images are combined using variance weighting and the output variance is derived from the input variances. The user may choose either KAPPA wcsmosaic or a combination of KAPPA wcsalign and CCDPACK makemos to mosaic the images.

The images may be (optionally) registered astrometrically to a given reference position. See the documentation for SCUBA2_REGISTER_IMAGES for more details.

The EXP_TIME (and WEIGHTS for SCUBA-2, EFF_TIME for ACSIS) NDF components are aligned to a common coordinate grid before adding together. The first image is used as the reference.

Creates a single output file based on the name of the last file in the list, and with a suffix "_mos" (e.g. mylastfile_mos.sdf).

Notes

Currently only works for a single source. Odd things may happen if multiple sources are given.

Files must contain data from JCMT instruments.

The same pixel-spreading method (and any associated parameters) is used for the data and the EXP_TIME and WEIGHTS.

With no parameters supplied, the recipe uses wcsmosaic and the nearest-neighbour pixel-spreading scheme.

Available recipe parameters

• MOSAIC_TASK

  • Name of mosaicking task to use, either wcsmosaic (default) or makemos

• MAKEMOS_METHOD

  • Image combination method for makemos, may be median, mean or sigmas - default is median (see makemos documentation in SUN/139 for advice on choosing the method)

• MAKEMOS_SIGMAS

  • Sigma-clipping threshold if MAKEMOS_METHOD is sigmas (default is 4)

• REGISTER_IMAGES
  • Flag to specify whether images should be registered before coadding. Default is 0 (no).
• REGISTER_RA

  • Right Ascension of reference position in HH:MM:SS.S format.

• REGISTER_DEC

  • Declination of reference position in DD:MM:SS.S format.

• WCSMOSAIC_METHOD

  • wcsmosaic and wcsalign pixel-spreading method: see wcsmosaic and/or wcsalign documentation for available options (default is "nearest")

• WCSMOSAIC_PARAMS

  • additional parameters which may be required for the chosen method (again, see wcsmosaic/wcsalign documentation in SUN/95)