Schmidt Triplet for ZTF

R. Dekany16 April 2013

Add refigured Schmidt singlet to existing Grubb-Parsons doublet

C a l t e c h O p t i c a l O b s e r v a t o r i e sR i c h a r d D e k a n y

z t f c _ t r i p l e t _ s c h m i d t _ w i t h _ w i n d o w _ a n d _ c o n t a c t _ m i r r o r _ b a l l _ F P A _ e x c e l l e n t . Z M X2 0 m a s p i x e l w / 1 2 8 x 1 2 8 F o V p e r s u b a p

3 D L a y o u tZ T F C4 / 1 6 / 2 0 1 3

X

Y

Z

C a l t e c h O p t i c a l O b s e r v a t o r i e sR i c h a r d D e k a n y

z t f c _ t r i p l e t _ s c h m i d t _ w i t h _ w i n d o w _ a n d _ c o n t a c t _ m i r r o r _ b a l l _ F P A _ e x c e l l e n t . Z M X2 0 m a s p i x e l w / 1 2 8 x 1 2 8 F o V p e r s u b a p

3 D L a y o u tZ T F C4 / 1 6 / 2 0 1 3

X

Y

Z

Features of latest design April 15

• Singlet remains plane parallel– Earlier quotes called for grinding a radius to one of the two existing

plane surfaces• New aspheric coefficient is about 70x smaller than the existing

coefficient– … if original design is simply optimized Schmidt– Therefore, the ‘refiguring’ process for the singlet is fundamentally

taking out much of the asphere• Insensitive to axial location for installation

– Could be either inside or outside existing doublet• Relatively insensitive to axial location

– 10 mm lateral misplacement barely affects image quality

Image quality(g’ shown)

• Evaluated assuming – g’ filter on inner 4 CCDs– R filter on outer 8 CCDs– … but it makes little

difference after reopimizing

• Field curvature under control– Same design IQ out

(beyond) corner of 16 CCD FPA

S u r f a c e I M A : C C D M o s a i c

60.00

O B J : 0 . 0 0 0 0 , 0 . 0 0 0 0 ( d e g )

I M A : - 4 8 . 0 5 2 , - 4 8 . 0 6 2 m m

O B J : 0 . 0 0 0 0 , 1 . 7 8 9 0 ( d e g )

I M A : - 4 8 . 0 5 2 , 4 7 . 5 5 1 m m

O B J : 1 . 7 8 9 0 , 1 . 7 8 9 0 ( d e g )

I M A : 4 7 . 5 0 8 , 4 7 . 5 1 6 m m

O B J : 0 . 8 9 4 5 , 0 . 8 9 4 5 ( d e g )

I M A : - 0 . 2 5 2 , - 0 . 2 5 4 m m

O B J : 1 . 7 8 9 0 , 0 . 0 0 0 0 ( d e g )

I M A : 4 7 . 5 6 1 , - 4 8 . 0 4 4 m m

C a l t e c h O p t i c a l O b s e r v a t o r i e sR i c h a r d D e k a n y

z t f c _ t r i p l e t _ s c h m i d t _ w i t h _ w i n d o w _ a n d _ c o n t a c t _ m i r r o r _ b a l l _ F P A _ e x c e l l e n t . Z M X2 0 m a s p i x e l w / 1 2 8 x 1 2 8 F o V p e r s u b a p

S p o t D i a g r a mZ T F C4 / 1 6 / 2 0 1 3 U n i t s a r e µ m . A i r y R a d i u s : 1 . 1 9 5 µ mF i e l d : 1 2 3 4 5R M S r a d i u s : 7 . 6 7 9 7 . 0 6 8 6 . 2 0 7 7 . 3 8 0 6 . 8 1 2G E O r a d i u s : 1 7 . 8 0 6 1 6 . 4 3 7 1 2 . 3 2 5 1 6 . 0 5 8 1 5 . 4 1 8S c a l e b a r : 6 0 R e f e r e n c e : C e n t r o i d

- 0 . 2- 0 . 1 0 00 . 0 0 0 . 20 . 1 0M i l l i m e t e r s P e r c e n t

+ Y + Y

F i e l d C u r v a t u r e D i s t o r t i o nS T S TS T

C a l t e c h O p t i c a l O b s e r v a t o r i e sR i c h a r d D e k a n y

z t f c _ t r i p l e t _ s c h m i d t _ w i t h _ w i n d o w _ a n d _ c o n t a c t _ m i r r o r _ b a l l _ F P A _ e x c e l l e n t . Z M X2 0 m a s p i x e l w / 1 2 8 x 1 2 8 F o V p e r s u b a p

F i e l d C u r v a t u r e / F - T a n ( T h e t a ) D i s t o r t i o nZ T F C4 / 1 6 / 2 0 1 3M a x i m u m F i e l d i s 2 . 5 3 0 D e g r e e s .W a v e l e n g t h s : 0 . 3 9 8 0 . 4 6 7 0 . 5 3 6

00

2

0 . 1 7 8 9

4

0 . 3 5 7 8

6

0 . 5 3 6 7

8

0 . 7 1 5 6

1 0

0 . 8 9 4 5

1 2

1 . 0 7 3

1 4

1 . 2 5 2

1 6

1 . 4 3 1

1 8

1 . 6 1

2 0

1 . 7 8 9

+ Y F i e l d i n D e g r e e s

C a l t e c h O p t i c a l O b s e r v a t o r i e sR i c h a r d D e k a n y

z t f c _ t r i p l e t _ s c h m i d t _ w i t h _ w i n d o w _ a n d _ c o n t a c t _ m i r r o r _ b a l l _ F P A _ e x c e l l e n t . Z M X2 0 m a s p i x e l w / 1 2 8 x 1 2 8 F o V p e r s u b a p

RMS Spot Radius in µ

m

R M S S p o t R a d i u s v s F i e l dZ T F C4 / 1 6 / 2 0 1 3P o l y 0 . 3 9 8 0 . 4 6 7 0 . 5 3 6

R e f e r e n c e : C e n t r o i d