;+ ; PROJECT: ; SDAC ; Name: ; BATSE_POINTING ; ; ; PURPOSE: ; Compute direction cosines for BATSE LAD's, SPECS for Solar Viewing ; Also find the position of the Sun and the Earth in the GRO coordinate ; system and report the respective azimuth and elevation angles in degrees ; ; ; CATEGORY: BATSE, data base extraction, needed for spectroscopy routines ; ; ; CALLING SEQUENCE: batse_pointing, fdb=fdb, flare=flare, ut=ut, $ ; xyz_pos=xyz_pos, zx_radec=zx_radec, $ ; cos_det=cos_det, cos_spec=cos_spec, $ ; sun_in_gro = sun_in_gro, earth_in_gro=earth_in_gro,$ ; quiet=quiet, erroro=error ; ; INPUTS: ; Supply either fdb, flare, or (xyz_pos & zx_radec & ut) ; fdb - A single packet of the BATSE data base structure ; containing housekeeping info with standard tag names ; x_pos, y_pos, z_pos, z_ra, z_dec, x_ra, x_dec ; flare - Extract single packet at peak of this flare. ; ut - If passed with flare number, will extract pointing info at ; this time instead of at peak of flare. Must be passed ; if calling with xyz_pos and zx_radec keywords. ; xyz_pos - x, y, z GRO position in 1/4 km units ; zx_radec - 4 element array with zra,zdec,xra,xdec of GRO pointing ; in .0001 rad units ; /quiet Inhibit print messages ; OUTPUTS: ; cos_det - direction cosines for LADs ; cos_spec- direction cosines for SPECs ; sun_in_gro - Position of the Sun in the GRO coordinate system, ; Phi, Theta - (long and latitude) (degrees) ; earth_in_gro - Position of the Geocenter in the GRO coordinate system, ; Phi, Theta (degrees) ; error - 0/1 means no error/error ; RESTRICTIONS: ; Requires that the GRO position vector and GRO pointing directions ; be defined at the flare peak or the chosen time (ut). It will fail ; on the 'Omni' data, (fdb.eng_telem=-1). ; ; MODIFICATION HISTORY: based on det_point and spec_point, ; written by RAS 3 Aug 1993 ; Mod. 7 Feb 94 by AKT. Added xyz_pos and zx_radec keywords. If user ; already has a data packet, can call batse_pointing with xyz_pos, ; zx_radec, and ut keywords to get pointing info. Also added ; error keyword. ; ras, 22-jun-1995, replaced crossp() with f_crossp() ;- pro batse_pointing, fdb=fdb, flare=flare, ut=ut, $ xyz_pos=xyz_pos, zx_radec=zx_radec, $ cos_det=cos_det, cos_spec=cos_spec, $ sun_in_gro = sun_in_gro, earth_in_gro=earth_in_gro, $ quiet=quiet, error=error ;ut - time in seconds from 79/1/1 corresponding to vectors x_ra, x_dec ;x_ra - GRO X-axis pointing direction right ascension in .0001 RAD ;x_dec -GRO X-axis pointing direction declination in .0001 RAD ;z_ra - GRO Z-axis pointing direction right ascension in .0001 RAD ;z_dec -GRO Z-axis pointing direction declination in .0001 RAD ;pnt_ndx - pointing index to start of new pointing direction, ref. to ut ;cos_det - direction cosines for each of BATSE LADs for each time sample ; cos_det is dimensioned fltarr(8,n_elements(ut)) ;****************************** if not keyword_set(quiet) then quiet = 0 if quiet then verbose = 0 else verbose = 1 if keyword_set(xyz_pos) and keyword_set(zx_radec) and keyword_set(ut) then begin sc = xyz_pos * 1. z_ra = zx_radec(0) z_dec = zx_radec(1) x_ra = zx_radec(2) x_dec = zx_radec(3) endif else begin if n_elements(fdb) eq 0 then begin checkvar, flare, 1 fs_open, flare=flare, dd_open=dd_open, dd_type=1, error=error, $ verbose=verbose if error then goto, error_exit read_flare, flare, flare_rec checkvar,ut, flare_rec.peak_secs find_packet, ut, dd_open, first_rec, error=error if error then goto, error_exit fstat = fstat(dd_open.lun) point_lun, dd_open.lun, first_rec*fstat.rec_len fdb = dd_open.data readu, dd_open.lun, fdb free_lun, dd_open.lun ;lu opened by find_dbfile endif ut = sc_seconds_ed(fdb.sctime) f = fdb ;shorten the typing for the structure sc = [f.x_pos,f.y_pos,f.z_pos] * 1. z_ra = f.z_ra & z_dec = f.z_dec & x_ra = f.x_ra & x_dec = f.x_dec endelse sc = sc /sqrt(total(sc^2)) ;unit vector for spacecraft position, sc wrt earth in ;inertial coordinates ;Convert X_RA and X_DEC from .0001 rad stored in integer*2 format ;to floating point in radians ;X_RA goes from 0 to 10000*2*!pi, unsigned ;X_DEC goes from -10000*!pi/2 to 10000*!pi/2 signed ;Interpret x_ra as the low 2 bytes of a longword x_ra_rad= (x_ra and 65535l)/1e4 ;ra in radians x_dec_rad=x_dec/1e4 ;declination in radians xc=transpose(sphcart(x_ra_rad*!radeg,x_dec_rad*!radeg)) ;3 by nx z_ra_rad= (z_ra and 65535l)/1e4 ;ra in radians z_dec_rad=z_dec/1e4 ;declination in radians zc=transpose(sphcart(z_ra_rad*!radeg,z_dec_rad*!radeg)) ;3 by nx yc=f_crossp(zc,xc) ;*************************** ;GET THE POSITION OF THE SUN IN CELESTIAL CARTESIAN COORDINATES ;Get Ra and Dec of the Sun at center of orbit sradec=solephut(ut) ;Vector to Sun in cartesian coordinates sunxyz=sphcart(sradec(0),sradec(1)) ;sunxyz is (1,3) ;;;;;;;;;;;;;;;;;;;;;;; Detectors' Aspects in Spacecraft Coordinates ;given the spacecraft z-axis as straight up along COMPTEL and the x-axis ;is pointed in the OSSE scan plane, find the direction cosines of the normals ;to the 8 BATSE LAD's batse=fltarr(3,8) index=indgen(1,8) for j=0,2 do batse(j,0)=sqrt(1/3.)*(-1)^(index/2^(2-j)) ;;;;;;;;;;;;;;;;;;;;;;;;; ;ADD SPECTROSCOPY DETECTORS POINTING zcos=batse(2,*) zang = acos(zcos)*!radeg zang2=zang+(-1)^index*19 zsin= sin(zang/!radeg) zcos2 = cos(zang2/!radeg) zsin2 = sin(zang2/!radeg) lad2spec = [ zsin2/zsin, zsin2/zsin, zcos2/zcos] spec = batse*lad2spec ;;;;;;;;;;;;;;;;;;;;;;;;; ;CREATE TRANSFORMATIONS FROM DETECTOR TO CELESTIAL COORDINATES x2fov=(reform([xc,yc,zc],3,3)) ;fov2x=transpose(x2fov) ;detector directions in celestial batsefov = x2fov#batse specfov = x2fov#spec ; (vector in celestial coord.)=(vec. in detector coor)# x2fov ;**************** ;COMPUTE THE DIRECTION COSINES TO THE SUN FOR EACH LAD FOR EACH SAMPLE cos_det = reform(sunxyz#reform(batsefov(*,*))) ;tran(1x3 # 3x8)=8 cos_spec= reform(sunxyz#reform(specfov(*,*))) ;tran(1x3 # 3x8)=8 ;Find the position of the Sun in the GRO coordinate system sun_in_gro = xyradec( sunxyz # x2fov ) ; ;Find the position of the geocenter in GRO coordinates ;sc is the position of the spacecraft in celestial wrt Earth (n x 3) earth_in_gro = xyradec(-sc#x2fov) ;n x 2, Phi and Theta earth_cos_det = reform( -sc#reform(batsefov(*,*))) earth_cos_spec = reform( -sc#reform(specfov(*,*))) if not quiet then begin print,'Position of the Sun in the GRO coordinate system, Phi, Theta (degrees)' print,sun_in_gro print,'Position of the Geocenter in the GRO coordinate system, Phi, Theta (degrees)' print,earth_in_gro endif goto, getout error_exit: print,'Error reading data file in BATSE_POINTING.' if keyword_set(flare) then print,'For flare ',flare getout: return &end