NAME

photpars -- edit the photometry parameters

USAGE

photpars

PARAMETERS

weighting = "constant"

The type of weighting for the WPHOT task. The weighting parameter is ignored by the PHOT task. The options are:

constant

Uniform weights of 1 for each pixel are used.

cone

A conical weighting function of full width half maximum fwhmpsf as defined in the DATAPARS parameter set is used.

gauss

A Gaussian weighting function of full width half maximum fwhmpsf as defined in the DATAPARS parameter set is used.

apertures = "3" (scale units)

A list of aperture radii in units of the scale parameter or the name of the file containing the list of aperture radii. List elements may be separated by whitespace or commas. A range syntax of the form ap1:apN:apstep is also supported.

zmag = 25.00

The zero point offset for the magnitude scale.

mkapert = no

Mark the photometry apertures on the displayed image ?

DESCRIPTION

The integral of the flux within the circular apertures specified by apertures is computed by summing pixels in the aperture with the specified weighting function weighting . The fraction of each pixel lying within the the aperture is computed by an approximation and all the approximations are summed. The zero point of the magnitude scale is determined by zmag .

Apertures is specified in units of the image scale. If scale is specified in units of the half-width at half-maximum of the point spread function the aperture per pixel a single value of apertures will work well on images with differing psfs.

EXAMPLES

1. List the PHOTPARS parameters.

    da> lpar photpars

2. Edit the PHOTPARS parameters.

    da> photpars

3. Edit the PHOTPARS parameters from within the PHOT task.

    da> epar phot

	... edit a few phot parameters

	... move to the photpars parameter and type :e

	... edit the photpars parameters and type :wq

	... finish editing the phot parameters and type :wq

4. Save the current PHOTPARS parameter set in a text file photnite1.par. This can also be done from inside a higher level task as in the above example.

    da> photpars

	... edit some parameters

	... type ":w photnite1.par"  from within epar

TIME REQUIREMENTS

BUGS

SEE ALSO

phot,wphot,radprof