;+
; NAME:
;   et2jd
;
; PURPOSE:
;   converts ET to julian date (ET = TDB seconds after J2000)
;
; DESCRIPTION:
;   converts ET to julian date (ET = TDB seconds after J2000)
;
; CALLING SEQUENCE:
;   jd = et2jd(et) 
;
; INPUTS:
;   et - may be a double, or an array or matrix of doubles
;
; KEYWORDS
; OUTPUTS:
;  jd - Julian date. Same dimensions as et.
; 
; PROCEDURE:
;  Calls cspice_et2jd to get the year, month, day;
;  raparse to get the fractional day, and
;  jdcnv to get the conversion to julian date.
;  REVISON HISTORY:
;   2006 Apr 12 Leslie Young.  Based on single_eph
;-

function et2jd, et, format=format, prec=prec

    naifinit

    day = 24.d * 3600.d

    if isarray(et) then begin
        dim = size(et, /dim)
        jd = make_array(dim,/double)
        n = n_elements(et)
        for i=0, n-1 do begin
            CSPICE_ET2UTC, et[i], 'ISOC', 0, utci  ; to nearest second
            year = fix(strmid(utci,0,4))
            month = fix(strmid(utci,5,2))
            day = fix(strmid(utci,8,2))
            hr = raparse(strmid(utci,11,8))*12.d/!dpi
            jdcnv, year, month, day, hr, jdi
            jd[i] = jdi + (et[i]-utc2et(utci))/day  ; get fractional seconds
        end
        return, jd
    endif else begin
        CSPICE_ET2UTC, et, 'ISOC', 0, utci ; to nearest second
        year = fix(strmid(utci,0,4))
        month = fix(strmid(utci,5,2))
        day = fix(strmid(utci,8,2))
        hr = raparse(strmid(utci,11,8))*12.d/!dpi
        jdcnv, year, month, day, hr, jdi
        jd = jdi + (et-utc2et(utci))/day ; get fractional seconds
        return, jd
    end
    
end