file: ifu_commands.txt

This file is a comprehensive crib sheet for the
available commands in the IMACS-IFU acquisition
IDL routines.

Written by Adam S. Bolton, MIT, 2005Aug03.

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In what follows, commands are shown preceded by the
"IDL> " prompt.  Don't type "IDL> " yourself.

When commands are shown as
  IDL> ifu_whatever, keyword=[value]
[value] should be replaced by an integer or float or
whatever else is called for, without the [] unless
otherwise noted.

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*** ifu_set:

IDL> ifu_set, camera='f2nods'
  - or -
IDL> ifu_set, camera='f4nods'
  If none of the ifu_ routines have been called since the
  start of the IDL session, these commands will initialize
  the routines for either f2 or f4 nod-and-shuffle dewar
  orientation.  Initial-guess spot positions are read from
  either 'spot_f2nods.txt' or 'spot_f4nods.txt'.

IDL> ifu_set, camera='f2nods', /reset
  - or -
IDL> ifu_set, camera='f4nods', /reset
  Same as above, but to re-initialize if the programs have
  already been used during the IDL session.  All previous
  spot positions will be forgotten.

IDL> ifu_set
  With no arguments, this is equivalent to
  "ifu_set, camera='f2nods'" if the routines have not yet
  been initialized.  If they have been initialized already,
  this command shows the current values of the routine
  parameters.

IDL> ifu_set, ylo=[integervalue]
IDL> ifu_set, yhi=[integervalue]
  Adjusts the extent of the region (in pixels) that is cut out
  of the CCD mosaic to make the IFU pseudoslit image.

IDL> ifu_set, count=[integervalue]
  Every time the spot positions are changed using ifu_tweak,
  the "count" is increased by one and the old values are
  remembered (until IDL quits).  You can restore previous
  spot positions with this command, referencing the appropriate
  "count" value from when they were active.  The current count
  value is shown whenever ifu_set is called.  Note that the
  current count value increases by one when this command is used,
  rather than actually going back to the value that is supplied.

IDL> ifu_set, spotrad=[integervalue]
  Set the radius (really the half-width) of the aperture boxes
  that are extracted about the spot positions to make the IFU
  image.  Units are pixels.

IDL> ifu_set, xspot=xspot, yspot=yspot
  Return the current spot positions in the vectors
  "xspot" and "yspot".


*** ifu_slit:

IDL> ifu_slit, frame='ccdXXXX'
  generate and display a pseudoslit image for the specified
  IMACS frame.  Needs access to chips 2 & 5 for f2N&S, and to
  chips 3 & * for f4N&S.

IDL> ifu_slit, frame='ccdXXXX', im=im
  Same as above, but also returns the slit image in the array "im".

IDL> ifu_slit, /replot
  Re-display the most recent slit image, form use if ifu_im has
  since been used to display a reconstructed focal-plane image.


*** ifu_spot:

IDL> ifu_spot
  Overplot assumed fiber spot positions on the slit image.


*** ifu_tweak:

IDL> ifu_tweak, [x1, dx1, dy1, x2, dx2, dy2]
  Adjust the assumed fiber-spot positions.
  Syntax is as shown including square brackets.
  x1 and x2 are x-pixel locations along the
  pseudo-slit image where shifts are specified,
  and dx1, dy1, dx2, dy2 are the x- and y-shifts
  that need to be applied to the assumed IFU spot
  positions at those locations in order to bring
  assumed positions to the correct positions.


*** ifu_im:

IDL> ifu_im         [,rawim=rawim, hexim=hexim]
  - or -
IDL> ifu_im, /bg    [,rawim=rawim, hexim=hexim]
  Reconstruct and display a hex-pixel focal-plane image
  by extracting apertures about the fiber spot positions,
  for the (Durham-convention) object or background aperture.
  The optional keywoords "rawim" and "hexim" can be used
  to return arrays containing the compact 25x40x2 (or 25x20x2)
  image data, or the oversampled hex-pixel version of it.

IDL> ifu_im, savename='flat'
  For saving a flat-field IFU acquisition image:
  the flatfield data will be saved to the file 'flat.fits'.

IDL> ifu_im, [/bg,] flatname='flat'
  Like "ifu_im" or "ifu_im, /bg", but also applies the
  flatfielding saved in 'flat.fits'