cplot - displays an ultracam image

cplot provides some basic display capability to look and examine at Ultracam frames. The profile fitting requires the data to be bias-subtracted to work completely correctly. This command also provides a way of examining statistics of an image.

Invocation

cplot data [device] nccd (cursor [stack]) xleft xright ylow yhigh iset (ilow ihigh)/(plow phigh) [width aspect reverse cheight font] applot (aperture) [fwhm hwidth readout gain symm beta sigrej onedsrch (fwhm1d hwidth1d) fdevice]

Command line arguments

data --- Ultracam data file or a list of Ultracam files. If the program fails to open it as an ultracam file, it will assume that it is a list.

device --- Display device

nccd --- The particular CCD to display, 0 for the whole lot

cursor --- Enable the cursor, but only for single CCD plots

stack --- Stacking direcion when plotting more than on CCD. Either in 'X' or 'Y'

xleft xright --- X range to plot

ylow yhigh --- Y range to plot

iset --- 'A', 'D' or 'P' according to whether you want to set the intensity limits automatically (= min to max), directly or with percentiles.

ilow ihigh --- If iset='d', ilow and ihigh specify the intensity range to plot

plow phigh --- If iset='p', plow and phigh are percentiles to set the intensity range, e.g. 10, 99

width --- Width of plot in inches. 0 for the default width.

aspect --- aspectd ratio (y/x) of the plot panel

reverse --- true/false to reverse the measuring of black and white.

cheight --- Character height, as a multiple of the default

font --- Character font, 1-4 PGPLOT fonts

lwidth --- Line width, integer multiple of default

applot --- true to plot an aperture file.

aperture --- If applot, this is the aperture file to plot.

fwhm --- This is the first of several parameters associated with profile fits (gaussian or moffat profiles). fwhm is the initial FWHM to use in either case.

hwidth --- The half-width of the region to be used when fitting a target. Should be larger than the fwhm, but not so large as to include multiple targets if possible.

readout --- Readout noise, RMS ADU in order for the program to come back with an uncertainty.

gain --- Gain, electrons/ADU, again for uncertainty estimates

symm --- Yes/no for symmetric versus ellliptical profile fits

beta --- The beta parameter of the moffat fits.

sigrej --- The fits can include rejection of poor pixels. This is the threshold, meaured in sigma. Should not be too small.

onedsrch --- Yes if you want an initial 1D search to be made. This is tolerant of poor positioning of the start point, but potentially vulnerable to problems with multiple targets. What happens is that a box around the cursor position is collpased in X and Y and then the peak in each direction is located using cross-correlation with a gaussian of FWHM=fwhm1D. This new position is then used to define the fitting region and initial position for the 2D gaussian fit.

fwhm1d --- This is the FWHM used in the 1D search. It does not have to match the FWHM of the target necessarily. In particular a somewhat larger value is less sensitive to initial position errors.

hwidth1d --- The half-width of the region to be used for searching for a target. The wider this is, the more chance of finding a target from a sloppy start position, but also the more chance of peaking up on a spurious target.

rstar --- If you carry out fits, the program also extracts a flux. It scales the aperture radii by the seeing. 'rstar' gives the multiple of the seeing to use for the target.

rsky1 --- If you carry out fits, the program also extracts a flux. It scales the aperture radii by the seeing. 'rsky1' gives the multiple of the seeing to use for the inner radius of the sky annulus.

rsky2 --- If you carry out fits, the program also extracts a flux. It scales the aperture radii by the seeing. 'rsky2' gives the multiple of the seeing to use for the outer radius of the sky annulus.

fdevice --- Plot device for showing Moffat & symmetrical gaussian fits. Should be different from the image plot device. e.g. "/xs" or "2/xs" if image plot device = "1/xs" otherwise the program will go belly up for reasons that I cannot quite track down. 'null' to ignore.

xbox --- The 'S' show command gives a few simple stats for the region the cursor is centered on such as the mean and median. This parameter specifies the half-size in X that will be used in terms of binned pixels. If the nearest pixel is at ix, the a range ix-xbox to ix+xbox will be used, but truncated at the edge of the window.

xbox --- The 'S' show command gives a few simple stats for the region the cursor is centered on such as the mean and median. This parameter specifies the half-size in Y that will be used in terms of binned pixels. If the nearest pixel is at iy, the a range iy-ybox to iy+ybox will be used, but truncated at the edge of the window.

Cursor commands

The cursor options are as follows

I	---	For 'In'. Zooms in around the current cursor position by a factor of 2
O	---	For 'Out'. Zooms out around the current cursor position by a factor of 2
G	---	For Gaussian. Performs a 2D gaussian fit. This proceeds as follows: first, a search is made over a box centred on the cursor position by collapsing in X and Y and performing a 1D gaussian cross-correlation. Then using this updated position, a 2D gaussian fit is made. This can either be symmetric or elliptical in shape. Note that the uncertainties reported rely on accurate readout and gain parameters having been supplied. There is one subtle feature of the gaussian fits: it fits to a blurred model profile as a way of preventing fits ot cosmic rays. Many other parameters are hidden command-line parameters that can be set if you specify 'prompt' on the command-line.
M	---	For Moffat. Performs a 2D Moffat profile fit, in much the same way as the Gaussian fit, but only symmetric Moffat profiles are allowed for. Starting parameters are hidden; specify prompt if you want to alter them.
L	---	For Levels. Change the plot levels.
W	---	For Whole. Display whole CCD.
S	---	Shows value of pixel corresponding to cursor position (no graphics scaling -- it gives you the true value), along with a few simple stats on the surrounding region specified using the hidden xbox and ybox parameters. These are the mean, rms, median, minimum and maximum values. The box is truncated at the edges.
Q	---	Quit

Classes

This command is a member of the classes: Display, Programs.

Author: T.R. Marsh
Created: 06 January 2005
Revised: 09 March 2006

Page generated Fri Jul 5 12:23:42 2013

data	---	Ultracam data file or a list of Ultracam files. If the program fails to open it as an ultracam file, it will assume that it is a list.
device	---	Display device
nccd	---	The particular CCD to display, 0 for the whole lot
cursor	---	Enable the cursor, but only for single CCD plots
stack	---	Stacking direcion when plotting more than on CCD. Either in 'X' or 'Y'
xleft xright	---	X range to plot
ylow yhigh	---	Y range to plot
iset	---	'A', 'D' or 'P' according to whether you want to set the intensity limits automatically (= min to max), directly or with percentiles.
ilow ihigh	---	If iset='d', ilow and ihigh specify the intensity range to plot
plow phigh	---	If iset='p', plow and phigh are percentiles to set the intensity range, e.g. 10, 99
width	---	Width of plot in inches. 0 for the default width.
aspect	---	aspectd ratio (y/x) of the plot panel
reverse	---	true/false to reverse the measuring of black and white.
cheight	---	Character height, as a multiple of the default
font	---	Character font, 1-4 PGPLOT fonts
lwidth	---	Line width, integer multiple of default
applot	---	true to plot an aperture file.
aperture	---	If applot, this is the aperture file to plot.
fwhm	---	This is the first of several parameters associated with profile fits (gaussian or moffat profiles). fwhm is the initial FWHM to use in either case.
hwidth	---	The half-width of the region to be used when fitting a target. Should be larger than the fwhm, but not so large as to include multiple targets if possible.
readout	---	Readout noise, RMS ADU in order for the program to come back with an uncertainty.
gain	---	Gain, electrons/ADU, again for uncertainty estimates
symm	---	Yes/no for symmetric versus ellliptical profile fits
beta	---	The beta parameter of the moffat fits.
sigrej	---	The fits can include rejection of poor pixels. This is the threshold, meaured in sigma. Should not be too small.
onedsrch	---	Yes if you want an initial 1D search to be made. This is tolerant of poor positioning of the start point, but potentially vulnerable to problems with multiple targets. What happens is that a box around the cursor position is collpased in X and Y and then the peak in each direction is located using cross-correlation with a gaussian of FWHM=fwhm1D. This new position is then used to define the fitting region and initial position for the 2D gaussian fit.
fwhm1d	---	This is the FWHM used in the 1D search. It does not have to match the FWHM of the target necessarily. In particular a somewhat larger value is less sensitive to initial position errors.
hwidth1d	---	The half-width of the region to be used for searching for a target. The wider this is, the more chance of finding a target from a sloppy start position, but also the more chance of peaking up on a spurious target.
rstar	---	If you carry out fits, the program also extracts a flux. It scales the aperture radii by the seeing. 'rstar' gives the multiple of the seeing to use for the target.
rsky1	---	If you carry out fits, the program also extracts a flux. It scales the aperture radii by the seeing. 'rsky1' gives the multiple of the seeing to use for the inner radius of the sky annulus.
rsky2	---	If you carry out fits, the program also extracts a flux. It scales the aperture radii by the seeing. 'rsky2' gives the multiple of the seeing to use for the outer radius of the sky annulus.
fdevice	---	Plot device for showing Moffat & symmetrical gaussian fits. Should be different from the image plot device. e.g. "/xs" or "2/xs" if image plot device = "1/xs" otherwise the program will go belly up for reasons that I cannot quite track down. 'null' to ignore.
xbox	---	The 'S' show command gives a few simple stats for the region the cursor is centered on such as the mean and median. This parameter specifies the half-size in X that will be used in terms of binned pixels. If the nearest pixel is at ix, the a range ix-xbox to ix+xbox will be used, but truncated at the edge of the window.
xbox	---	The 'S' show command gives a few simple stats for the region the cursor is centered on such as the mean and median. This parameter specifies the half-size in Y that will be used in terms of binned pixels. If the nearest pixel is at iy, the a range iy-ybox to iy+ybox will be used, but truncated at the edge of the window.