NAME:
	ra_fictitious_sun
 PURPOSE:
	Returns right ascension of fictitious sun for specified UT time
 CATEGORY:
	gen/idl/ephem
 CALLING SEQUENCE:
	FUNCTION ra_fictitious_sun, tt, degrees=degrees, scalar=scalar
 INPUTS:
	tt	array; standard time structure
 OPTIONAL INPUT PARAMETERS:
	/degrees    if set, returned RA is in degrees; default: radians
 OUTPUTS:
	ra	scalar or array; right ascension
 INCLUDE:
	@compile_opt.pro	; On error, return to caller
 CALLS: ***
	AngleRange, TimeGet, ToDegrees
 CALLED BY:
	cv, smei_sgp4_orbits
 PROCEDURE:
 MODIFICATION HISTORY:
	MAR-2011, Paul Hick (UCSD/CASS; pphick@ucsd.edu)

 NAME:
	rank_array
 PURPOSE:
	Calculates rank array for a given index array
 CATEGORY:
	gen/idl/toolbox/math
 CALLING SEQUENCE:
	rank = rank_array(index)
 INPUTS:
	index	    array; type: integer
			index array, i.e. array of indices returned
			by the IDL sort function
 OUTPUTS:
	rank	    array; type: integer
			rank array
 INCLUDE:
	@compile_opt.pro	; On error, return to caller
 CALLS: ***
	IsType
 CALLED BY:
	boost
 PROCEDURE:
	The rank array inverts the index array. Applying rank to the sorted
	array returns the array back into its original order: A[rank[index]] = A
 MODIFICATION HISTORY:
	JAN-2002, Paul Hick (UCSD/CASS; pphick@ucsd.edu)

 NAME:
	RGBO_DepthCue
 PURPOSE:
	Returns a matte matrix for a depth cue operation
 CATEGORY:
	gen/idl/toolbox/graphics
 CALLING SEQUENCE:
	PRO RGBO_DepthCue, cue_depth=cue_depth, size=sz, dimension=dimension, matte=matte
 INPUTS:
	cue_depth=cue_depth scalar or array[2]; type: float
				scalar is interpreted as [depth,depth]
				depth[0]: opacity at maximum depth
				depth[1]: power applied to dropoff from minimum to
				maximum depth (should be positive)
 OPTIONAL INPUT PARAMETERS:
	size=sz 	    array; type: integer
				IDL size vector for 3D array
				only the dimensions sz[1:sz[0]] are used
	dimension=dimension array[3]; type: integer
				dimensions of 3D array

				Either one of these keyword is used to specify the dimensions
				of a 3D array [N,L,M]

	matte=matte	    array[N,L,M]; type: float
				The matte matrix for the depth cue is multiplied into
				the input matte, if it exists
 OUTPUTS:
	matte=matte	    array[N,L,M]; type: float
				resulting matte matrix (input matte times depth cue matte)
 INCLUDE:
	@compile_opt.pro	    ; On error, return to caller
 CALLS: ***
	IsType, SuperArray
 CALLED BY:
	RemoteView_Display3D
 SEE ALSO:
	RGBO_Project
 PROCEDURE:
	The 3rd dimension of M is taken to be the z-dimension.
	m=0 has maximum depth (farthest away from the viewer) and gets opacity
	depth[0]. m=M-1 has minimum depth (nearest to the viewer) and gets opacity
	of one. The dropoff between the two is given by the power value:
	    o = depth[0]+(1-depth[0])*( z/(ndim[2]-1)  )^depth[1]
	The resulting values are constrained to stay between 0 and 1.
 MODIFICATION HISTORY:
	AUG-2002, Paul Hick (UCSD/CASS; pphick@ucsd.edu)

 NAME:
	RGBO_Project
 PURPOSE:
	Merges content of z-buffer with color and opacity
	array of volume data set
 CATEGORY:

 CALLING SEQUENCE:
	FUNCTION RGBO_Project, zvol, rgbo, $
	    zpix	= zpix		, $
	    zbuf	= zbuf		, $
	    ctrgb	= ctrgb 	, $
	    background	= background	, $
	    bad_data	= bad_data	, $
	    bad_opacity = bad_opacity	, $
	    low_data	= low_data	, $
	    low_opacity = low_opacity	, $
	    high_data	= high_data	, $
	    high_opacity= high_opacity	, $
	    matte	= matte
 INPUTS:
	zvol		array[N,M,L]; type: byte
			    byte array for volume data
	rgbo		array[256,4]; type; float
			    rgbo vector; rgbo[*,0]=o*r, rgbo[*,1]=o*g, rgbo[*,2]=o*b
			    rgbo[*,3] = o*255. o = opacity (0 <= o <= 1), r,g,b = red,green
			    blue color indices (0 <= r,g,b <= 255).
 OPTIONAL INPUT PARAMETERS:
	zpix=zpix	array[n,m]; type: byte
			    Z-buffer content (the Z-buffer iis a 256-color device)
			array[n,m,3]; type: byte
			    Z-buffer content as true color image
	zbuf=zbuf	array[n,m]; type: integer
			    Z-buffer depth array
	background=background
			scalar; type: byte
			    background color index in Z-buffer
			    If not specified then !p.background is used.
			array[3]; type: byte
			    (only if zpix is true color image)
			    background color rgb values in Z-buffer
	ctrgb=ctrgb	array[256,3]; type: byte
			    (only if zpix is 256-color image)
			    rgb values for color table to be used to interpret zpix
			    If not specified then the current color table is retrieved
			    with the IDL tvlct function.
	matte=matte	array[N,M,L] or array[N,M,L,4]
			    matrix of values between 0 and 1 to be applied to
			    zvol after conversion to rgbo values and before projecting onto
			    the image plane. This can be used e.g. to implement depth cueing.
			    An array[N,M,L] is applied to each channel (r,g,b,o).
 OUTPUTS:
 OPTIONAL OUTPUT PARAMETERS:
 INCLUDE:
	@compile_opt.pro	    ; On error, return to caller
 CALLS: ***
	ArrayLocation, CONGRID, InitVar, IsType, SuperArray
 CALLED BY:
	RemoteView_Display3D
 SEE ALSO:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
	JUL-2002, Paul Hick (UCSD/CASS; pphick@ucsd.edu)

 NAME:
	run_ssw
 PURPOSE:
	IDL main program to update the SSW help files.
 CATEGORY:
	www_help
 CALLING SEQUENCE:
	idl $pro/run_ssw
 INPUTS:
	(none)
 OUTPUTS:
	(html files)
 CALLS:
	www_help_sync.py, www_help_tree
 PROCEDURE:
	After completion IDL exits again.
 MODIFICATION HISTORY:
	JAN-2002, Paul Hick (UCSD/CASS)
	FEB-2003, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
	    Added www_help_sync.py call

 NAME:
	run_ssw_smei
 PURPOSE:
	IDL main program to update the SSW help files.
 CATEGORY:
	www_help
 CALLING SEQUENCE:
	idl run_ssw_smei
 INPUTS:
	(none)
 OUTPUTS:
	(html files)
 CALLS:
	do_file, www_help_tree
 PROCEDURE:
	After completion IDL exits again.
 MODIFICATION HISTORY:
	JAN-2002, Paul Hick (UCSD/CASS)
	FEB-2003, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
	    Added www_help_sync.py call