1. INTERACTIVE NON-LINEAR CURVE FITTING CURSOR OPTIONS

?	Print options
a	Abort current fit (don't update table)
b	Define baseline for Gaussians
c	Print the coordinates and fit of point nearest the cursor
d	Delete data point nearest the cursor
f	Fit the data and redraw or overplot
g	Redefine graph keys.  Any of the following data types may be along
	either axis.
	    x  Independent variable	y  Dependent variable
	    f  Fitted value		r  Residual (y - f)
	    d  Ratio (y / f)            n  Non-linear component
h-l	Graph keys.  Defaults are h=(x,y), i=(y,x), j=(x,r), k=(x,d), l=(x,n)
o	Overplot the next graph
p	Define Gaussian amplitudes and positions
q	Exit the interactive curve fitting.  Carriage return will also exit.
r	Redraw graph
s	Set sample range with the cursor
t	Initialize the sample range to all points
u	Undelete the deleted point nearest the cursor
w	Set the graph window.  For help type 'w' followed by '?'.
x	Change the x value of the point nearest the cursor
y	Change the y value of the point nearest the cursor
z	Print cursor WCS coordinates
I	Interrupt task immediately


2. INTERACTIVE NON-LINEAR CURVE FITTING COLON COMMANDS

The parameters are listed or set with the following commands which may be
abbreviated.  To list the value of a parameter type the command alone.
Function coefficients need an index i.

:function [value]	Fitting function
:user [value]		User function
:coef i [value]         i-th function coefficient
:var  [i]               Vary i-th coefficient. If i not supplied, vary all.
:fix  [i]               Fix i-th coefficient. If i not supplied, fix all.
:ngauss [value]         Number of Gaussians
:chisq [file]		Show the fit's chi-sq
:rms [file]		Show the fit's rms
:show [file]		Show the values of all parameters and coefficients
:vshow [file]		Idem above, plus all data points
:ltype [value]		Set line type (continuous|boxes)
:pcomp [value]          Plot individual function components ? (y/n)
:xaxis [value]		Type of x axis (linear|log)
:yaxis [value]		Type of y axis (linear|log|mag)
:mag0 [value]		Constant for magnitude axis plotting
:resample [value]       Coefficient errors by resampling (y/n)
:verbose [value]        Iteration info switch (y/n)
:maxit [value]          Maximum number of iterations
:method [value]		Minimization method (amoeba / Levenberg-Marquardt)
:restart [value]        Number of restarts
:replic [value]         Number of replicated samples for error estimation
:alpha [value]		Simplex control constant
:beta [value]		Simplex control constant
:gamma [value]		Simplex control constant
:grow [value]		Rejection growing radius
:naverage [value]	Sample averaging or medianing window
:low_reject [value]	Low rejection threshold
:high_reject [value]	High rejection threshold
:niterate [value]	Number of rejection iterations
:sample [value]		Sample ranges

Additional commands are available for setting graph formats and manipulating
the graphics.  Use the following commands for help.

:/help			Print help for graph formatting option
:.help			Print help for general graphics options


3. INTERACTIVE CURVE FITTING GRAPH KEYS

The graph keys are h, i, j, k and l.  The graph keys may be redefined to
put any combination of axes types along either graph axis with the 'g' key.
To define a graph key select the desired key to redefine and then specify
the axes types for the horizontal and vertical axes by a pair of comma
separated types from the following:

d  Ratio (y / f)
f  Fitted values
r  Residuals of fit (y - f)
x  Indepedent variable
y  Dependent variable (data being fit)
n  Linear component removed from dependent variable.

4. FUNCTION COEFFICIENTS

Function coefficients specified by [i] in the colon commands :COEF, :VAR and
:FIX are specific of each functional form, in the following way:

   i	POWERLAW	BBODY		TWOBBODY	COMPOSITE	

   1	exponent	temperature	temp. 1		p.l. exponent
   2	amplitude	amplitude	ampl. 1		p.l. amplitude
   3	ref. x		ref. lambda	ref.  1		p.l. ref. lambda
   4					temp. 2		b.b. temperature
   5					ampl. 2		b.b. amplitude
   6					ref.  2		b.b. ref. lambda

   i	GAUSSIANS	CGAUSS				GALPROF

   1    zero            zero                            se - bulge brigth.
   2    slope           slope                           re - bulge radius 
   3	ampl. 1		ampl. 1				s0 - disk brigth. 
   4	cent. 1		cent. 1				r0 - disk radius  
   5	fwhm  1		fwhm  1				r1 - "hole" radius
   6	ampl. 2		ampl. 2 (relative)		backgr- background
   7	cent. 2		cent. 2 (relative)
   8	fwhm  2		fwhm  2	
   .	 ...		 ...