;docformat = 'rst'
;+
;Calculate ESP pointing in alpha/beta and heliocentric latitude and longitude.
;This routine calculates the position of the ESP quadrant diode center
;of brightness in alpha and beta, explained below, and presuming that the spacecraft is
;properly pointed at the center of the Sun, the corresponding heliocentric latitude and
;longitude of the center of brightness.
; :Params:
; diodes: in, required
; calibrated/dark-corrected diode values. Can be quadrant fraction. These values are normalized before use.
; Array of 4 values, index 0 to 3 match up with quadrant diode names Q0-Q3
; jd: in, required
; julian date of observation
;:Keywords:
; alpha: out
; Solar alpha angle (E/W) in arcminutes. Positive when center of brightness is east/left of ESP axis
; beta: out
; Solar beta angle (N/S) in arcminutes. Positive when center of brightness is north/above ESP axis
; latitude: out
; Heliocentric latitude of ESP center, in degrees, positive north, taking into account the B0 nodding
; longitude: out
; Heliocentric longitude of ESP center, in degrees, sub-earth longitude is zero.
;:Categories:
; utility
;-
pro esp_calc_pointing,diodes,jd,alpha=alp,beta=bet,latitude=lat,longitude=lon
esp_quad_to_ab,diodes,alp=alp,bet=bet
sam_ab_to_ll,jd,alp,bet,lat=lat,lon=lon
end