ATMOFIT
Name
atmofit
Purpose (one Line)
Fit 1 or 2 gaussians to an astronomical image that is seeing limited.
Description
Category
Function fitting
Calling Sequence
atmofit,image,loc,guess,sub,resa,a,sigmaa,chisq
Inputs
image - 2-d data array to be fitted
loc - 4 element vector that specifies where to look in the image
for an object to fit. This is passed to boxm to look for
the image maximum. The components are:
loc(0) - X center of box.
loc(1) - Y center of box.
loc(2) - Half width of box in the X direction.
loc(3) - Half width of box in the Y direction.
guess - Initial value guesses for the image fitting process. There
are two possibilites:
1) one star (object) fit - guess is a scalar value that
is a guess at the 1/e width
2) two star (object) fit - guess is a three element vector
guess(0) = 1/e width of seeing
guess(1) = X location of fainter star relative to the
center of the brighter object
guess(2) = Y location of fainter star relative to the
center of the brighter object
Optional Input Parameters
Keyword Parameters
FILE - string containing the FITS file name to read for image.
If read, then input parameter image is overwritten and
returned.
FORCE - If guess is set up for two stars, this forces the solution
for the second position relative to the first if set.
WIDTH - Number of pixels to attempt to extract from around the peak
pixel. Subarray will be at most 2*WIDTH+1 square.
Extraction is truncated by the edge of the array.
Default is FIX( GUESS(0)*5.0 + 0.5 )
DISPLAY - Show extraction, model fit and residual images on the
current display window. Value indicates the zoom factor
for the displayed images.
Outputs
sub - Extracted piece of image.
resa - Model fit to sub.
a - Coefficients of the fit.
sigmaa - Uncertainties of the fitting coefficients.
chisq - Reduced chi-squared of the fit to sub.
KEYWORD OUTPUTS:
ERR - uncertainty on MAG.
MAG - returns the magnitude of the object (scalar for a star,
three element vector for 2 gaussians [total, bigger, smaller]
Common Blocks
Side Effects
Restrictions
Procedure
Modification History