; Minimum Science Mission Grid Characteristics for HESSI, File for IDL Prog. Gd.pro
; This Version, 4/21/95 , includes 7 grids
; File Gd_7_a.dat
; Formulae
; 
; Resolution (grid #) = 10^( log(2)+(grid#-1)*(log(120)-log(2))/ngrids-1 )
; (Grid Resolutions are even divisions on a logarithmic scale, of the range
;  between the coarsest and finest grid)
;
; Pitch = 2.0*(coll. Length)*Tan(Resolution *pi/6.48e5)  (Tan radians)
; Slit Width = Pitch * (Slit Width/Pitch Ratio)
; Slat Width = 1 - Slit Width
; Thickness = Slit Width / Tan (1.0 * pi/180) if FOV is set (Tan radians)
; Field of View = Arctan(Slit Width/Thickness) if Thickness is set (deg.)
;
; 
1750.	; Collimator Length (mm)
71.	; Bottom Collimator Diameter (mm)
9.	; Top Collimator Diameter (mm)
.3	; Angular Overlap (degrees)
2.0	; Finest Angular Resolution (arc seconds)
120.	; Coarsest Angular Resolution (arc seconds)
;Coll. Res.     Pitch  Slit    Slat  Slit  Thick. FOV  SET   Density  Locat.  Orient. Shape Slat      
; #    arc       mm    Width   Width Width/  mm   deg. 0-Th. g/cm^3 	0-out  deg.  1-sq.  Material  
;      sec              mm      mm   Pitch             1-FOV 	  	1-in         0-cir          
1      2.00    0.034   0.020   .0136   .6  0.025 38.66   0    19.3	0     0.0     1     Gold      
2      2.90    0.049   0.030   0.020   .6  0.050 30.96   1    19.3	0     67.5    1     Gold      
4      6.11    0.104   0.062   0.041   .6  1.000 03.55   1    19.3	0     22.5    1     Gold      
6      12.86   0.218   0.131   0.087   .6  1.000 07.46   1    19.3	0     157.5   0     Gold      
8      27.08   0.459   0.276   0.184   .6  1.000 15.43   1    19.3	0     112.5   0     Gold      
10     57.00   0.967   .580    .387    .6  1.000 30.11   0    19.3	0     67.5    0     Tungsten  
12     120.00  2.036   1.120   0.916   .55 1.000 48.24   0    19.3	0     22.5    0     Tungsten