;+ ; NAME: ; HXA_PARMS ; PURPOSE: ; Returns numerical values of various parameters used in suncenter ; calculations, including HXA detector properties. ; ; This second version returns updated and corrected parameters. ; Note: the use of cox, coy has slightly changed. The polynomial ; is not in time since sunrise in minutes, but tofac*t/(t_lms-t_fms). ; CATEGORY: ; CALLING SEQUENCE: ; hxa_parms,... ; INPUTS: ; KEYWORDS (INPUT): ; OUTPUTS: ; KEYWORDS (OUTPUT): ; hpix = HXA pixel size (in arcseconds) ; h_xx, h_yy = HXA detector crossing point coordinates ; spix = SXT pixel size (Note: in hxa_suncenter: spix = hpix/spix!) ; phi = angle between SXT (E->W) and HXA (SE->NW) ; sxt_off = SXT coordinates of HXA detector crossing point ; naban_o = offset between NaBan filter image and SXT X-ray image ; wdban_o = offset between WdBan filter image and SXT X-ray image ; cox, coy = coefficients for orbital phase correction ; tofac = multiplier for orbital phase ; clx, cly = coefficients for orbit duration correction ; tloff = time offset for orbit duration correction (in minutes) ; cmx, cmy = coefficients for mission time correction ; tmoff = time offset for mission time correction (in days) ; tmcut = last day for which mission time correction shall be applied ; gpix = gyro unit (in arcseconds) ; COMMON BLOCKS: ; None. ; SIDE EFFECTS: ; RESTRICTIONS: ; correction coefficients cmx, cmy only work for first year of ; mission. A zero correction is ok for 1993 and early 1994. ; This correction cannot be predicted for future times. ; PROCEDURE: ; MODIFICATION HISTORY: ; 19-Jul-93 (JPW) - Constants mostly from hxa-suncenter. ; 20-Sep-94 (JPW) - Updated parameters, plus cutoff date for ; mission time correction ; 24-sep-94 (SLF) - added VERSION keyword (output), Set VERSION=1 ; 3-oct-96 (JPW) - set VERSION=2, to reflect modified hxa2hxaxy ;- pro hxa_parms,hpix=hpix,h_xx=h_xx,h_yy=h_yy,spix=spix,phi=phi, $ sxt_off=sxt_off,naban_o=naban_o,wdban_o=wdban_o, $ cox=cox,coy=coy,tofac=tofac,clx=clx,cly=cly,tloff=tloff, $ cmx=cmx,cmy=cmy,tmoff=tmoff,tmcut=tmcut,gpix=gpix, $ version=version ;----------------------------------------------------------------------- ; old constants used until Sep-94 ; ;VERSION=0 ; historical comment / slf, 24-sep-94 ;hpix = 2.072 ; factor hxa -> sun_r ;h_xx = 1006.0 ; hxa axes cross at x = h_xx ;h_yy = 1038.0 ; hxa axes cross at y = h_yy ;spix = 2.455 ; slightly different to gt_pix_size, replace only after checking ; ; consistency of all parameters ;gpix = 0.08 ; gyro unit (in arcseconds) ;phi = 44.35 ;sxt_off = [503.6 + 0.36, 665.1 - 1.47] ;sxt_off = sxt_off + 0.5 ; pixel def. OFR -> FRE (21-jul-93 JPW) ;naban_o = [-0.36, +1.47] ;wdban_o = [-0.36 + 0.6, +1.47 - 0.2] ;cox = [+0.21,-6.23e-4,+1.82e-7] ; coefficients for orbital time correction ;coy = [+1.22,-1.326e-3,+2.82e-7] ;clx = [0.0, 0.0, 0.0] ;cly = [+0.32,+1.198e-3,-1.019e-6] ; coefficients for orbit duration (y only) ;tloff = 4000.0/60.0 ; time offset for orbit duration (min.) ;cmx = [+1.88,-3.130e-3,+1.068e-6] ; coefficients for mission correction ;cmy = [-8.57,+1.889e-2,-1.024e-5] ; as of Sept. 1992 ;tmoff = 4000 ; day offset for mission time corr. (days) ; ;ttt = [1.0,60.0,3.6e3] ; converts constants for use with times in minutes ;cox = cox*ttt ;coy = coy*ttt ;clx = clx*ttt ;cly = cly*ttt ;----------------------------------------------------------------------- ; Sources of the updated constants below: ; 1. hpix, h_xx, h_yy ; Parameters determined by fitting all available hxa data of offpoints ; for which none of the solar limb was hidden behind a fiducial mark. ; Program: find_hxaparm1.pro (uses the atr database). ; The results agree very well with Masuda's results. ; Note: this hxa pixel size is only used to reconstruct the hidden limbs, ; and has been tuned to best serve this purpose. There may be a small ; difference between hpix and the actual hxa plate scale. ; 2. spix, phi ; Two methods: a) fit sxc and atr data for all offpoints, ; b) co-register all images of a particularly well-observed set of E-W ; offpoints on 8-may-92. ; Method a) uses many observations of lower accuracy, and method b) ; uses fewer observations of higher accuracy. ; Programs: a) do_hpix_phi.pro, b) run_s_h_limbs.pro and hxa_sxt_phi_r.pro. ; Note: spix is only used for the hxa to sxt pixel size ration (hpix/spix), ; thus the programs determine this ratio. Official (red book) value is ; 0.8460, but the Mercury passage observations indicate that the SXT ; pixel size is actually slightly larger (2.455"). The value for spix is ; hpix divided by the average of methods a) and b) (=0.8450). ; The average for phi is 44.33 degrees, consistent with Masuda's 44.35. ; 3. gpix ; Determine gpix/hpix with atr data of offpoints throughout the mission. ; The ratio varies with time, especially when a gyro starts having ; problems (shortly before the switch to the S-gyro). The adopted ratio ; is an average for good gyro's. The resulting gyro "plate scale" is ; 0.082"/step (larger than the official 0.080"/step). ; Program: find_iruparm2.pro. ; 4. sxt_off, cox/y, clx/y, cmx/y, tloff, tmoff, tmcut ; Determine the offset between SXT and the crossing points of the hxa ; detectors using the sxc database. Determine the coefficients for ; three time-dependant corrections: orbital phase correction (cox/y), ; orbital length correction (clx/y), time into mission correction (cmx/y). ; The time into mission correction is most significant for the first ; year of the mission, and flattened out thereafter. Future significant ; deviations are possible but cannot be predicted. tmcut indicates the ; last day for which the mission correction can be applied, for later dates ; the correction shall be 0. ; Programs: off_sxt_nab.pro and do_sxt_off.pro. ; Note: the values for tofac, tloff, and tmoff are definitions. ; The various correction coefficients are for 2nd degree polynomials in ; time (tofac*t/(t_lms-t_fms) for cox/y (new def.!), minutes for clx/y, ; days for cmx/y). The polynomial fit works well for the first two ; correction, but only up to jan-93 for the mission correction. ; 5. Offset between SXT and aspect telescope. The offset is different for ; the two optical filters. Metcalf determined the offset between ; SXT and the NaBan images and Wuelser determined the offset between ; the two optical filters in 1992. These values are within 0.10 pixels ; of the average of all SXC and SOT suncenter locations until fall 1992. ; (Program off_sxt_nab.pro. This program corrects for a 0.4 pixel offset ; between suncenter locations obtained with the old and new sxt_center ; algorithm. That offset in turn was determined by comparing old and new ; SXC suncenter positions for the (random) weeks 92_20, 92_25, 92_26 ,92_27. ; Result: sunc_new_x - sunc_old_x = 0.0 , sunc_new_y - sunc_old_y = +0.40). ;VERSION=1 ; slf, 24-sep-1994 VERSION=2 ; jpw, 3-oct-1996 ; version=2 indicates modified hxa2hxaxy, ; even though hxa_parms was not changed ; Updated constants hpix = 2.073 ; factor hxa -> sun_r h_xx = 1006.0 ; hxa axes cross at x = h_xx h_yy = 1039.0 ; hxa axes cross at y = h_yy spix = hpix/0.8450 ; 0.845 is best estimate for hpix/spix phi = 44.33 ; angle between hxa and sxt gpix = hpix*0.0396 ; gyro unit (in arcseconds) sxt_off = [504.76, 663.19] ; average loc. of hxa crossing pt. on SXT cox = [+0.31,-4.10e-2,+7.52e-4] ; coefficients for orbital time correction coy = [+0.97,-7.14e-2,+9.83e-4] tofac = 60.0 ; multiplier for relative orbital phase clx = [+0.06,+1.60e-2,-1.31e-3] ; coefficients for orbit duration cly = [+0.31,+9.03e-2,-4.76e-3] tloff = 4000.0/60.0 ; time offset for orbit duration (min.) cmx = [ +4.09, -7.69e-3, +3.62e-6] ; coefficients for mission correction cmy = [-10.50,+2.389e-2,-1.299e-5] ; use only up to 1-jan-93, (0 thereafter) tmoff = 4000 ; day offset for mission time corr. (days) tmcut = 5115 ; end day for mission corr. (1-jan-93) naban_o = [-0.36, +1.47] ; offset betw. NaBan and SXT sunc. loc. wdban_o = [-0.36 + 0.6, +1.47 - 0.2] ; offset betw. WdBan and SXT sunc. loc. end