66 DR. R A. SA MI-SUN: A CASSRUAIX REFLECTOR WITH CORRECTED FIELD. 



Final Scheme. 

 (Jivat mirror- 

 Aperture .... - = 40 ' 



Radius of curvature R = -400'000, 



e ,,= +' 16468. 



c?, = +132'013. 

 Revereer 



Aperture ...... 2 2 = 16<2 



First surface ..... R, = +211 '603, 



Silvered surface R' 2 = +221'289, 



Thickness ... < 2 = 2-000. 



d,= +90-676. 

 Corrector, 1st lens- 

 Aperture 2 4 = 12'2, 



First surface R 4 = -144'298, 



Second surface R' 4 = +48 "824, 



Thickness . t t = 1'250. 



d 6 = +0'500. 

 Corrector, 2nd lens- 

 Aperture 2a 6 = 12'6, 



First surface R 6 = -4138'559, 



Second surface R' 6 = -38'285, 



Thickness t e 1'500. 



d 7 = +71-377. 



Focal length /'. = +508'802. 



Distance of principal focus beyond 



surface of great mirror +33"290. 



Whole length of instrument .... 167'3. 



Specification of Field at /8 = "01 = tan 34'"4. 



H = T5200. /x = 1-5352. [Newtonian.] 



" // // 



Radius of least circle of aljerration . . O'OOO 0"007 O'OO 



Radius of comatic circle . . . -0'005 +0'069 +0'80 



Radius of focal circle , +0'370 +0'566 -0'41 



Distortional displacement +6'75 +7"13 O'OO. 



Curvature of fi.-l.l -1/16282 -l/542'3 -1/508'8. 



