	Interactive Keystroke Commands

?	Print help
:	Colon commands
v	Verify the critical parameters
w	Save the current parameters
d	Plot radial profile of current star 
i	Interactively set parameters using current star
f	Fit sky for current star
spbar	Fit sky for current star, output results
m	Move to next star in coordinate list
m	Fit sky for next star in coordinate list, output results
l	Fit sky for remaining stars in coordinate list, output results
e	Print error messages
r	Rewind the coordinate list
q	Exit task


        Colon commands

:show	[data/sky]	List the parameters
:m [n]	Move to the next [nth] star in coordinate list
:n [n]	Fit sky to next [nth] star in coordinate list, output results

	Colon Parameter Editing Commands

# Image and file name parameters

:image		[string]	Image name
:coords		[string]	Coordinate file name
:output 	[string]	Output file name

# Data dependent parameters

:scale		[value]		Image scale (units per pixel)
:fwhmpsf	[value]		Full width half maximum PSF (scale units)
:emission	[y/n]		Emission feature (y), absorption (n)
:sigma		[value]		Standard deviation of sky (counts)
:datamin	[value]		Minimum good pixel value (counts)
:datamax	[value]		Maximum good pixel value (counts)

# Noise parameters

:noise		[string]	Noise model (constant|poisson)
:gain		[string]	Gain image header keyword
:ccdread	[string]	Readout noise image header keyword
:epadu		[value]		Gain (electrons per adu)
:readnoise	[value]		Readout noise (electrons)

# Observations parameters

:exposure	[string]	Exposure time image header keyword
:airmass	[string]	Airmass image header keyword
:filter		[string]	Filter image header keyword
:obstime	[string]	Time of observation image header keyword
:itime		[value]		Exposure time (time units)
:xairmass	[value]		Airmass value (number)
:ifilter	[string]	Filter id string
:otime		[string]	Time of observation (time units)

# Sky fitting algorithm parameters

:salgorithm	[string]	Sky fitting algorithm 
:skyvalue	[value]		User supplied sky value (counts)
:annulus 	[value]		Inner radius of sky annulus (scale units)
:dannulus	[value]		Width of sky annulus (scale units)
:khist		[value]		Sky histogram extent (+/- sky sigma)
:smooth		[y/n]		Lucy smooth the sky histogram 
:binsize	[value]		Resolution of sky histogram (sky sigma)
:smaxiter	[value]		Maximum number of iterations
:sloclip	[value]		Low side clipping factor (percent)
:shiclip	[value]		High side clipping factor (percent)
:snreject	[value]		Maximum number of rejection cycles
:sloreject	[value]		Low side pixel rejection limits (sky sigma)
:shireject	[value]		High side pixel rejection limits (sky sigma)
:rgrow		[value]		Region growing radius (scale units)

# Marking and plotting parameters

:mksky		[y/n]		Mark sky annuli on the display
:radplot	[y/n]		Plot radial profile of sky pixels
