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aoperf: NAOMI/INGRID AO performance tool

aoperf can be used to analyse one or more images and will report performance parameters including FWHM, Strehl ratio, half encircled energy radius and energy within 0.5 arcseconds.
Images will be pre-processed according to the parameters given when aoperf is called. Post-pre subtraction is done automatically if the input file contains two frames, dark image subtraction if a dark image file is specified and flat field normalisation if a flat-field image is given.
For information on the pre-processing options, see the ipre guide.
The invocation can be:
> aoperf -d dark.fits -C

or for a list of files:
> aoperf -d dark.fits -CT r00000?.fit

Pre-processing options including dark image subtraction and hot-pixel removal (-C) is usually required to get the program to locate the stellar image. If the program still homes in on a hot pixel, use the -P option to specify the desired coordinates manually. Dark subtraction is usually not required since the -C option normally takes care about single outlying pixels. The output is normally shown in a comprehensive manner. Use the -T flag to produce output in a tabular format.
Most options are determined from the FITS headers, but can be overridden on the command line. These include:

  • -1 {diameter} - Diameter of primary mirror
  • -2 {diameter} - Diameter of secondary mirror
  • -S {size} - PSF extraction box size(must be a power of two)
  • -l '{lambda0} {dlambda}' - Central wavelength and bandpass of filter
  • -s {pixelscale} - Pixel scal in arcseconds per pixel
  • -r {star radius} - Radius of star image in arcseconds
  • -R '{inner radius} {outer radius}' - Radius of sky annulus in arcseconds
The background value is calculated from the sky annulus unless a value is given on the command line with:
  • -b {counts} - background value
The position of the star for which to measure the performance is computed from the highest peak in the image (after pre-processing), unless the -P options is given:
  • -P 'x y' - peak coordinates
Additionally, the -g option can be invoked to produce a file containing the generated optimal PSF, and the -w option can be invoked to write the pre-processed image to an output file:
  • -g - generate PSF file : 'psf_strehl.fits'
  • -w {outfile} - write pre-processed data to a FITS file for inspection
Output is normally printed in a detailed fashion for each file provided. The -T switch produces a tabular format with the data for each file on one line. The lines are more than 80 characters, but can be seen as one line by resizing the terminal.
  • -T - generate output in table format
The camera is normally identified from the FITS header INSTRUME keyword. If the fits file provided does not contain this keyword, some switches will set apropriate default values. All will set the telescope parameters appropriate for the WHT, and a pixel scale as shown below:
  • -I - INGRID, pixel scale = 0.038
  • -K - TEK1, pixel scale = 0.033
  • -G - SBIG, pixel scale = 0.025
Filters are normally identified from the INGF1NAM keyword, which works well for INGRID. Filters in wheel 2 (INGF2NAM) will override wheel 1 if the wheel is not in the clear position. This means that if filter 2 is not completely inside the filter 1 bandpass, the cut by filter 1 is not taken into account. For other instruments, or INGRID images without full header the -B switch is provided to allow easy setting of the filter bandwidths. Allowed filter names are:
  • -B ks - K short band
  • -B k - K band
  • -B h - H band
  • -B j - J band
  • -B z - Z band as seen by INGRID (detector cutoff included)
  • -B Z - Z band as seen by typical CCD (detector cutoff included)
  • -B I - I band
  • -B R - R band
  • -B 1 - Oasis dichroic 1 bandpass
  • -B 2 - Oasis dichroic 2 bandpass
  • -B 3 - Oasis dichroic 3 bandpass

© 2002 Isaac Newton Group of Telescopes
Developed by Roy Østensen

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Last modified: 02 March 2013