pstar [sky=] [rms=] [nrow=] [ncol=] [colgrad=] [rowgrad=] [input=fname] [outfile=] [gain=] [photon] [wcs] [seed=] [star=counts,row,col,fwhm] ... [disk=counts,row,col,rad] [cross=counts,row,col,rad] [field=nstar,max,min,fwhm] ... [grid=nstar,max,min,fwhm] ... [sinewave=amp,freq[,phase] [verbose] [bitpix=] [clip] [wcs] [iso=] [wcsrot=]
The command line parameters are recorded in the FITS header,including the location of star so that they can be extracted later.
bitpix= The output file defaults to 16 bits signed integer but can be changed to 32 bit integer by this option. You can do unsigned short by using bitpix=20 (this is a cfitsio option).
clip - truncates values at 65535.
colgrad= sets a background slope across columns in adu/column. starting at column 0.
field= genderates a random fields of stars ranging in brightness from max to min . The stars are printed out.
gain= sets the conversion from photons to analog to digital converter units.
grid= generates an even array of stars with diminishing intensity with rows.. The stars are printed out.
input= allows you to read a file containing star row/col positions as output from the stars command.
ncol= changes the number of columns in the image (default: 256).
nrow= changes the number of rows in the image (default: 256).
outfile= changes the output filename (default: pstar.fits).
photon - Poisson distribution of that mean value is substituted. generates Poisson noise rather than a Gaussian.
rms= sets the root mean square noise level.
rowgrad= sets a background slope across rows in adu/column. starting at row 0.
seed= changes the random number generator start value (default:1).
sinewave- inserts as Sine waves on the image by specifying the amplitude, frequency and phase. The amplitude is zero to peak. The frequency is cycles per pixel (so frequency should be less than 1.). The phase of 0 degrees sends waves in columns, 90 in rows, and other values have the waves travelling at an angle.
sky= sets a general background in adu. It is noiseless.
star=count,row,col,fwhm places a single Gaussian stars of peak value row, column center, and full Width at Half Maximum. option.
disk=count,row,col,rad places a single uniform disk peak value row, column center, and radius. Only one disk is allowed.
cross=count,row,col,rad places a single crosshair peak value row, column center, and radius. Only one crosshair is allowed.
wcs- puts a kludgy World Coordinate System value in.
iso= changes MJD-OBS added to WCS.
pstar star=2800,10,22.4,5.3
Makes a 64x64 image in the file pstar.fits with an artificial star at (10, 22) and a peak pixel count of 2800 photons. The image is `noise free'
pstar star=2800,10,22.4,5.3 sky=10 star=1000,18,22,5.3
Does the same as the above but adds a background sky component, and a nearby fainter companion with photon noise.
pstar star=2800,10,22.4,5.3 photon
A field of stars can be generated by using the field command line argument. You must specify the number of stars, the maximum integrated intensity in counts, the minimum intensity in counts, and the fwhm. The program will generate the requested number of stars with integrated intensities between the maximum and minimum values randomly distributed in a logarithmic manner and distributed randomly about the image. The program prints out a list similar to that put out by stars of the coordinates. The coordinates can also be found in the FITS header.
The rand() function used to generate the random numbers is system supplied and has poor spectral properties so deficiencies in the generator may appear in some studies.
The photon noise feature is very slow.