NAME:
      high_mag_lat  
PURPOSE:
       To compute magnetic latitude of the orbit and plot the times
	of high latitude and passage through the ovals

SAMPLE CALLING SEQUENCE:
       high_mag_lat,['21-may-98 12:00','22-may-98 12:00'],latm,times $
	  lowlat=45, oval=[50,70]
INPUTS:
	timerange - Array of start and stop dates & times
	lowlat - lower limit for high latitude region (default = 40 degrees mag)
	oval - array of low and upper magnetic latitude limits for oval 
	  boundaries (default = [50,70])
	Assumes North magnetic pole at latitude = 78.5 and longitude = -70
OUTPUTS
	latm  - output array of magnetic latitude
	times - output array of times for latm
 CALLS: ***
	CLEAR_UTPLOT [1], CLEAR_UTPLOT [2], OUTPLOT [1], OUTPLOT [2], OUTPLOT [3]
	UTPLOT [1], UTPLOT [2], UTPLOT [3], UTPLOT [4], UTPLOT [5], UTPLOT [6], gtt_orbit
	sprint, timegrid
HISTORY:
        Written 19-May-98 by TDT
	21-Oct-2002 (TDT)  Fix no-SAA bug, change SAA symbol