addstar image photfile psfimage addimage
image
The list of images to which artificial stars are to be added.
photfile
The list of photometry files containing the x and y coordinates and magnitudes
of the
artificial stars to be added to image. If photfile is null (""),
then
nstar artificial stars uniformly distributed in position, and
between minmag and maxmag in magnitude, are added to image.
If photfile is is defined, there must be one photometry file for
every input image.
Photfile may be a simple text file containing x, y, magnitude, and id
number in
columns 1, 2, 3, and 4 respectively (simple_text = yes), an APPHOT/DAOPHOT
text database file (simple_text = no), or an STSDAS binary table file.
psfimage
The list of PSF images computed by the DAOPHOT PSF task. If psfimage
is "default", "dir$default", or a directory specification, then ADDSTAR
will look for a file with the name image.psf.?, where ? is the highest
existing version number. Otherwise psfimage must specify one PSF
image for every input image.
addimage
The root name of output artificial image.
If addimage is "default", "dir$default" or a directory specification,
then an output artificial image and artificial star list called image.add.? and
image.art.? respectively are created, where ? is the next available version
number. Otherwise there must be one output image for every
input image.
If the DAOPHOT package parameter text is "yes", then an APPHOT/DAOPHOT
text database file is written, otherwise an STSDAS binary table is written.
minmag
The minimum magnitude of the computer generated artificial stars to be
added to the image. The actual intensities of the pixels in the artificial
stars are computed with respect to the magnitude of the PSF stored in
psfimage.
maxmag
The maximum magnitude of the computer generated artificial stars to be
added to the image. The actual intensities of the pixels in the artificial
stars are computed with respect to the magnitude of the PSF stored in
psfimage.
nstar
The number of computer generated artificial stars to be added to the input
image.
datapars =
The text file in which the data dependent parameters are stored.
The gain parameter epadu in electrons per ADU is stored here.
If datapars is null ("") then the default parameter set in the
user's uparm directory will be used.
daopars =
The text file in which the daophot fitting parameters are stored.
The PSF radius parameter psfrad in scale units is stored here.
If daopars is null ("") then the default parameter set in the
user's uparm directory will be used.
seed = 0
The seed for the random number generator.
idoffset = 0
The integer offset to be added to the id numbers of stars in the output
artificial photometry file. By default the artificial stars are numbered from 1
to N where N is the number of artificial stars added to the input frame.
nimage = 1
The number of output images to be created per input image.
simple_text = no
If photfile is a text file and simple_text = "no", then
ADDSTAR expects an APPHOT/DAOPHOT database. Otherwise ADDSTAR expects
a simple list format with x, y, magnitude, and id in columns 1, 2,3, and 4
respectively.
verbose = )_.verbose
Print messages about the progress of ADDSTAR? Verbose may be set to the
daophot package parameter value (the default), "yes", or "no".
verify = )_.verify
Verify the critical ADDSTAR task parameters? Verify may be set to the
daophot package parameter value (the default), "yes", or "no".
update = )_.update
Update the critical ADDSTAR task parameters if verify = "yes"?
Update may be set to the daophot package parameter value (the default),
"yes", or "no".
ADDSTAR adds artificial stars, whose positions and magnitudes are listed in photfile or generated at random by the computer, to the input image image using the PSF in psfimage, and writes the result to the output image and output photometry file addimage. If photfile is null ("") then ADDSTAR generates an artificial photometry list containing nstar stars uniformly distributed in position over the image and in magnitude between minmag and maxmag. The input photometry file may be an STSDAS binary table or an APPHOT/DAOPHOT text database file (the output of the PHOT, PSF, PEAK, NSTAR, or ALLSTAR tasks) or a simple text file with the x and y positions, magnitude, and id in columns 1, 2, 3 and 4 respectively. The ids of stars in the output photometry file may be set to numbers outside the range of the real data by setting the parameter offset. Several output images may be written for each input image by setting the parameter nimage greater than 1.
The intensities in the artificial stellar images are computed relative to the intensities in the PSF image, by scaling the magnitudes of the artificial stars to the magnitude of the PSF in psfimage. Poisson noise is added to the artificial stars using the value of the gain stored in the image header keyword specified by the DATAPARS parameter gain if present, or the value of the DATAPARS parameter epadu.
If verbose = yes, a line of output is written to the terminal for each artificial star added to the input image.
Full output is written to the output photometry file addimage. At the beginning of each file is a header listing the current values of all the parameters. For each artifical star added to the input image the following record is written.
id xcenter ycenter mag
Id is the id number of the star, xcenter and ycenter are its coordinates, and mag is its magnitude.
1. Add 30 stars uniformly distributed between 17 and 20th magnitude and in position to the input image m92. Display the new image and mark the artificial stars.
da> addstar m92 "" m92.psf.1 "default" 17.0 20.0 30
da> display m92.add.1 1
da> pdump m92.art.1 xcenter,ycenter yes | tvmark 1 STDIN point=3
2. Add the artificial stars in the simple text file artdata to the same image.
da> addstar m92 artdata m92.psf.1 "default" simple+