diff options
Diffstat (limited to 'noao/digiphot/daophot/doc/seepsf.hlp')
| -rw-r--r-- | noao/digiphot/daophot/doc/seepsf.hlp | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/noao/digiphot/daophot/doc/seepsf.hlp b/noao/digiphot/daophot/doc/seepsf.hlp new file mode 100644 index 00000000..ed7a5728 --- /dev/null +++ b/noao/digiphot/daophot/doc/seepsf.hlp @@ -0,0 +1,101 @@ +.help seepsf May00 noao.digiphot.daophot +.ih +NAME +seepsf -- convert a sampled PSF lookup table to a PSF image +.ih +USAGE +seepsf psfimage image +.ih +PARAMETERS +.ls psfimage +The list of input PSF images computed by the PSF task. Each PSF image consists +of the parameters of a 2D analytic function stored in the image header and an +optional sampled lookup table of residuals from that fit stored in the image +pixels. +.le +.ls image +The list of output PSF images consisting of the sum of the analytic function +and the residuals in the lookup table. There must be one output PSF image for +each input PSF image. +.le +.ls dimension = INDEF +The dimensions of the output PSF image. By default \fIimage\fR is a 2D image +with dimensions of N by N where N = 2 * nint (psfrad / scale) + 1 with the +same scale as the original image from which \fIpsfimage\fR was derived. +\fIPsfrad\fR is the PSF fitting radius stored in the \fIpsfimage\fR image +header parameter "PSFRAD". \fIScale\fR is the image scale stored in the image +header parameter "SCALE". +.le +.ls xpsf = INDEF +The x coordinate of the output PSF. \fIXpsf\fR is only used if \fIpsfimage\fR +was computed with the variable PSF parameter \fIvarorder\fR in the DAOPARS task +set to > 0. +.le +.ls ypsf = INDEF +The y coordinate of the output PSF. \fIYpsf\fR is only used if \fIpsfimage\fR +was computed with the variable PSF parameter \fIvarorder\fR in the DAOPARS task +set to > 0. +.le +.ls magnitude = INDEF +The intensity scale of the output PSF. By default the intensity scale is set by +the magnitude of the first star used by the PSF task to compute \fIpsfimage\fR. +This parameter is stored in the keyword "PSFMAG" in \fIpsfimage\fR. +.le +.ih +DESCRIPTION +SEEPSF takes the input PSF \fIpsfimage\fR computed by the PSF task, consisting +of the parameters of a 2D analytic function stored in the image header and an +optional lookup table of residuals from the fit stored in the image pixels, and +computes an output PSF, \fIimage\fR, consisting of the sum of the analytic +function and the residuals. + +By default \fIimage\fR is a 2D image of dimensions N by N where N = 2 * nint +(psfrad) + 1 and the scale of \fIimage\fR is the same as the scale of the +original image from which \fIpsfimage\fR was derived. If \fIdimension\fR is +greater or less than N then the output PSF is block-averaged or subsampled with +respect to the original image. \fIPsfrad\fR is the value of the psf radius +parameter in the task DAOPARS used to compute \fIpsfimage\fR and is stored in +the \fIpsfimage\fR header parameter "PSFRAD". + +If \fIpsfimage\fR was computed with the variable PSF parameter \fIvarorder\fR +set to > 0, then \fIimage\fR is computed at a point (xpsf, ypsf) defined +relative to the original image. By default \fIimage\fR is computed at the +centroid of the PSF defined by the \fIpsfimage\fR header parameters "XPSF" +and "YPSF". + +The intensity scale of \fIimage\fR is determined by the value of \fImagnitude\fR +relative to the magnitude of the PSF. By default the output PSF has the +magnitude of the first PSF star stored in the \fIpsfimage\fR header parameter +"PSFMAG". + +SEEPSF is most commonly used for visualizing the PSF in image scale coordinates +and checking the form of any variability as a function of position. However +\fIimage\fR can also be used as input to other image processing program, for +example it might be used as the kernel in a convolution operation. + +.ih +EXAMPLES + +1. Compute the output PSF in image scale coordinates of PSF function +for image dev$ypix. + +.nf + da> seepsf ypix.psf.3 ypixpsf +.fi + +2. Compute the output PSF in image scale coordinates of the variable +PSF for the image m92b at position (113.63,50.48) pixels relative to the +original image. + +.nf + da> seepsf m92b.psf.2 m92psf xpsf=113.63 ypsf=50.48 +.fi + +.ih +TIME REQUIREMENTS +.ih +BUGS +.ih +SEE ALSO +datapars,daopars,psf +.endhelp |