NAME:
	NewcombSun
 PURPOSE:
	Calculates the true ecliptic coordinates (longitude, latitude and
	distance) of the Sun according to Newcomb's theory of solar motion.
	See O. Montenbruck, Practical Ephemeris Calculations, par. 4.1.2, p. 66.
 CATEGORY:
	smei/gen/idl/ephem
 CALLING SEQUENCE:
	FUNCTION NewcombSun, UT, $
	    Precision	= Precision	, $
	    Longitude	= Longitude	, $
	    Latitude	= Latitude	, $
	    Distance	= Distance	, $
	    diskradius	= DiskRadius	, $
	    parallax	= Parallax	, $
	    degrees	= Degrees	, $
	    heliocentric=Heliocentric
 INPUTS:
	UT	array; type: standard time structure
		    times (UT)
 OPTIONAL INPUTS:
	/Precision	if set, perturbations by several planets are
			taken into account
	/Longitude	if set, return ecl. longitude
	/Latitude	if set, return ecl. latitude
	/Distance	if set, return Sun-Earth distance
		(in neither of the tree keywords LONGITUDE,LATITUDE,
		 and DISTANCE is set, all three quantities are returned)
	/Degrees	if set, return angles in degrees (default: radians)
	/Heliocentric	if set, the longitude and latitude of Earth are returned
			(180 degrees is added to the longitude, the latitude
			is multiplied by -1, the distance is the same)
 OUTPUTS:
	Result	array; type: double
			cliptic coordinates of the Sun
			ecliptic longitude and latitude (degrees or radians)
			and Sun-Earth distance in AU
	    If only one coordinate (longitude, latitude or distance) is
	    requested then the structure of the output array the same as for T.
	    If more than one coordinate is requested the output array has an
	    additional leading dimension with 2 or 3 elements. The leading dimension
	    contains longitude, latitude and distance, in that order.
 OPTIONAL OUTPUTS:
	Diskradius	radius of Sun in arcsec
	Parallax	horizontal parallax in arcsec
 INCLUDE:
	@compile_opt.pro	; On error, return to caller
 CALLS: ***
	InitVar, SyncDims, TimeGet, ToRadians
 CALLED BY:
	jpl_test
 SEE ALSO:
	jpl_eph, jpl_test
 RESTRICTIONS:
	The calculation of Diskradius and Parallax needs the Sun-Earth
	distance. Hence the keyword /Distance must be set or all three
	keywords /Distance, /Longitude and /Latitude should be omitted.
 PROCEDURE:
	DLP long period perturbation of solar mean longitude and mean
	    anomaly
	G   mean anomaly of the Sun
	LO  = DLO+SLO/3600 = mean longitude of Sun
	DL  difference between true and mean solar longitude according to
	    two body problem
	The precision calculation includes perturbations by planets, oscillatory
	terms with amplitudes less than 8".

	The alternative way to calculate the geocentric location of the
	Sun or the heliocentric location of the Earth is to use jpl_eph
	(or equivalently, big_eph). In most of our IDL code NewcombSun
	calls, have been replaced by big_eph calls.

	The following two calls should give essentially the same result:
	p = NewcombSun(tt,/precision,/degrees)
	p = big_eph(tt,body='sun',center='earth',/degrees,/to_sphere,/to_ecliptic,/precess)

	A check with the Astronomical Almanac shows:
	(All times are at midnight on the day given)

		    Normal	Precision   Almanac
	1971	Jan 1	Lng 279.9114	279.91575   279 54' 57.0"  (279.91583)
		Lat   0.	0.38"	    0.42"
		Dist	0.9832947   0.9833006	0.9832998
	1974	Jan 1	Lng 280.1882	280.1874    280 11' 14.94" (280.1875)
		Lat   0.
		Dist
	1979	Jan 1	Lng 279.9702	279.9708    279 58' 14.90" (279.9708)
		Lat   0.
		Dist
	1989	Jan 1	Lng 280.5535	280.5525    280 33' 10.44" (280.5529)
		Lat   0.
		Dist
 MODIFICATION HISTORY:
	1989, Paul Hick (MPAE,UCSD)
	10/24/91, Tom Davidson : accuracy test
	AUG-1993, Paul Hick, extension of SunEclLong
	FEB-1998, Paul Hick (UCSD/CASS, pphick@ucsd.edu)
	    modified to accept multi-dimensional input arrays
	    added keyword /heliocentric
	    replaced keyword /radians by keyword /degrees

 NAME:
	next_contiguous_group
 CALLING SEQUENCE:
	FUNCTION next_contiguous_group, indx, count=count
 INCLUDE:
	@compile_opt.pro
 CALLS: ***
	InitVar, destroyvar, init_contiguous_group
 CALLED BY:
	init_contiguous_group, smei_hdr_plot
 COMMON:
	common next_contiguous_group_common, n, m, p, nmin

 NAME:
	nso_fe_plot
 PURPOSE:
	Plot synoptic maps for Fe XIV and Fe X data
 CALLING SEQUENCE:
	nso_fe_plot
 OPTIONAL INPUTS:
	All input keywords for nso_fe_read are permitted.
 OPTIONAL OUTPUTS:
 CALLS: ***
	Carrington, InitVar, PlotSynopticMap, TimeOp, TimeSet, nso_fe_read
 PROCEDURE:
>	Green and red maps are calibrated using the constant calibration
	for post-1989 observations.
>	Temperatures are calculated by taking ratios of the green and red
	arrays, i.e. this assumes that the first scan of green and red map
	are taken at the same time.
 MODIFICATION HISTORY:
	SEP-2003, Paul Hick (UCSD/CASS; pphick@ucsd.edu)

 NAME:
	nso_fe_read
 PURPOSE:
	Read red (Fe X), green (Fe XIV) or yellow (Ca XV) synoptic map from file
 CATEGORY:
	NSO
 CALLING SEQUENCE:
	map = nso_fe_read( /green_line, /calibrate, source=source)
 INPUTS:
 OPTIONAL INPUT PARAMETERS:
	source=source	scalar; type: string; default: $SSW_SMEI_DAT/map/sacpeak
			    location of Sac Peak maps

	The type of data read is set using one of the following keywords:

	/temperature	get temperature map
	/green_line	get green line map  (same as line = 'g')
	/red_line	get red line map    (same as line = 'r')
	/yellow_line	get yellow line map (same as line = 'y')
	line=line	scalar; type: string
			    'g','r' or 'y'.

	If none of these are set then line='g' is assumed.
	Keyword /temperature results in two recursive calls to nso_fe_read to read a
	green and a red map, and calculate the temperature map from the ratio.
	The 'line' setting is also used to limit the files presented in the IDL
	pickfile dialog.

	rotation=rotation
			scalar; type: integer; default: none
	limb		scalar; type: string
			    limb indicator, 'ww', 'we', 'ew' or 'ee'
	/bestlimb	if set this override the input 'limb' setting and forces
			reading of the 'best limb' map.
	height=height	integer; type: scalar; default: 115 ('g' and 'r') or 113 ('y')
			    scan height in solar radii, times 100 (i.e. 115, 125, 135 or 145)

	If 'rotation' and 'limb' (or /bestlimb) are set than the IDL pickfile dialog
	is NOT called and a file name is constructed (also using 'line' and 'height').

	/calibrate	if set the green and red data are scaled using the post-1989 calibration:
			    Map = 3.49*0.693*Map    Green
			    Map = 2.88*0.543*Map    Red
			The yellow line is never calibrated
	silent=silent	controls messages to screen
 OUTPUTS:
	map		array[32,61]; type: float
			    line intensities for 32 daily scans (coverng a little more than
			    one Carrington rotation).
	error		scalar; type: string
			    error string returned by flt_read
			    error = '' after successfull read
	line		scalar; type: string
			    'g', 'r' or 'y'
	rotation	scalar; type: integer
			    Carrington rotation number
	limb		scalar; type: string
			    limb indicator, 'ww', 'we', 'ew' or 'ee'
	height		scalar; type: integer
			    scan height in solar radii, times 100 (i.e. 115, 125, 135 or 145)
	utstart 	array[1]; type: time structure
			    start time for map (=time of first scan)
 CALLS: ***
	FILEPATH, GetFileSpec, InitVar, IsType, SetFileSpec, flt_read, flt_string
	nso_fe_start, nso_fe_temperature
 CALLED BY:
	nso_fe_plot
 PROCEDURE:
	The default location for the Sac Peak files is directory $SSW_SMEI_DAT/map/sacpeak
 MODIFICATION HISTORY:
	JUL-2001, Paul Hick (UCSD/CASS)
	SEP-2003, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
	    Rewrite

 NAME:
	nso_fe_start
 PURPOSE:
	Retrieves the exact start time for an NSO Fe XIV, Fe X or Ca XV synoptic map
 CATEGORY:
	gen/idl/toolbox/nso_fe
 CALLING SEQUENCE:
	status = nso_fe_start(rotation, limb_select, line=line, $
	    utstart=utstart, limb=limb, height=height)
 INPUTS:
	rotation	scalar; type: integer
			    Carrington rotation number
	limb_select	scalar; type: string
			    one of 'ww','ee','ew','we'
			    If not set then the best limb is used (as identified by the
			    plus sign in the sacpeak.* files).
 OPTIONAL INPUT PARAMETERS:
	line=line	scalar; type: string; default: 'g'
			    one of 'g', 'r', 'y'
			    coronal line id: green (Fe XIV), red (Fe X) or yellow (Ca XV)
	height=height	integer; type: scalar; default: 115 ('g' and 'r') or 113 ('y')
			    scan height in solar radii, times 100 (i.e. 115, 125, 135 or 145)
	/silent 	controls messages
 OUTPUTS:
	status		0: no start time found (utstart and limb do not exist)
			1: start time found
			    output variables utstart and limb will only exist if status=1.
 OPTIONAL OUTPUT PARAMETERS:
	error=error	scalar; type: string
			    error string if status=0; null string if status=1
	utstart=utstart
			array[1]; type: time structure
			    start time of synoptic map
	limb=limb	scalar; type: string
			    one of 'ww','we','ee','ew'
			    Same as limb_select if it was set, or else the 'best limb'
 CALLS: ***
	ArrayLocation, FILEPATH, InitVar, TimeSet, destroyvar, flt_read, who_am_i
 CALLED BY:
	nso_fe_read
 RESTRICTIONS:
	The startimes are stored in three files sacpeak.xiv, sacpeak.x and sacpeak.ca
	stored in the same directory ast this routine.
 PROCEDURE:
 MODIFICATION HISTORY:
	JUL-2001, Paul Hick (UCSD/CASS)
	NOV-2003, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
	    Complete rewrite.

 NAME:
	nso_fe_temperature
 PURPOSE:
	Temperature estimate from ratio of red and green intensity
 CATEGORY:
	NSO
 CALLING SEQUENCE:
	T = nso_fe_temperature, green, red
 INPUTS:
	green	    array; type: float
			green (Fe XIV) intensity
	red	    array; type: float
			red (Fe X) intensity
 OUTPUTS:
	T	    array; type: float
			temperatures (in MK??)
 CALLS: ***
	BadValue
 CALLED BY:
	nso_fe_read
 PROCEDURE:
	Where both intensity are <= zero no temperature is
	calculated (returned as !values.f_nan)
	The temperature is calculated from
	    T = 0.138645-0.0717*alog10(red/green)
	Where only the green intensity is available the temperature
	is set to the maximum temperature Where only the red intensity
	 is available the temperature is set to the minimum temperature
 MODIFICATION HISTORY:
	JUL-2001, Paul Hick (UCSD/CASS; pphick@ucsd.edu)