AXES: Compute the Centroid of an Object in an Image

This command will find the centroid of an object within the specified box in the source image, or in the entire image if no box specifier is given. The centroid coordinates are loaded into VISTA variables AXR and AXC, and are also held in a common block for use by other routines. If the W= keyword is used, the wavelength of the centroid of the spectrum in the given interval is loaded into the variable WAVE.

The routine uses the highest pixel value on the box perimeter as a threshold value for the centroid, unless the SKY word is given, in which case the argument of the SKY word is taken as the threshold. The threshold is subtracted from each pixel in the box during the calculation.

The output of AXES can be redirected.