[Raytrace] How to Specify a Schmidt Corrector in Oslo?
Michael Lindner
mikell@optonline.net
Sat, 13 Apr 2002 15:15:07 -0400
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As an exercise in learning about Oslo, and about ray tracing in general, I am
entering all the examples from Rutten and van Venrooij's book. I got all the
way to the Schmidt camera, and find myself stymied.
First off, R&V don't say which side of the corrector they put the figure on,
but I don't believe it matters much (and in the drawing they provide, they
show it on the inside). But my real problem lies in figuring out how to enter
the parameter for teh schmidt corrector.
R&V specify 3 numbers, A, B, and C, whcih they define in terms of
Z = Ah^2 + Bh^4 + Ch^6
whereas Oslo has a radius of curvature and 4th, 6th, etc. order deformation
coefficients. I translated the R&V parameters as follows:
Since a parbola is defined by
Z = h^2/2R
I entered 2/A for the radius of curvature of the back side of the corrector
(front is flat), made the back side a conic with a conic constant of -1
(parabola), and entered the "B" and "C" terms from R&V as the 4th and 6th
order deformation coefficients.
This produces a horrible design that doesn't even come close to decent
performance. Am I doing it wrong? Attached is the Oslo file.
--
Michael Lindner
Personal Page http://home.att.net/~mikel
S*T*A*R Astronomy Club http://www.starastronomy.org
The ATM Site http://www.atmsite.org
Telescope Making Web Ring
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// OSLO 6.1 18726 16418 46625
LEN NEW "200mm Schmidt f/3" -599.22 4
EBR 100.0
GIH 20.0
DES "OSLO"
UNI 1.0
SNO6 "geniierf_lt 0.0494835687547 25.0 1.00 -0.90 0.90 0.80 -0.80 0.80 0.70 1.0 1.0"
// SRF 0
AIR
TH 1.0e+20
AP 3.3376610369e+18
NXT // SRF 1
GLA BK7
RD -2.40408e+05
TH 6.0
AP CHK 100.0
CC -1.0
AD 2.74057192e-10
AE 2.90241421e-16
NXT // SRF 2
AIR
RD 4.0e+23
TH 1200.0
AP 100.0
NXT // SRF 3
RFH
TCE 0.0
RD -1200.0
TH -598.431
CC 7.6755
NXT // SRF 4
AIR
RD -600.0
TH 11.149060415244
CBK 1
WV 0.58756 0.48613 0.65627
WW 1.0 1.0 1.0
END 4
DLID 405.0
DLRS 3
DLAS On
SDSA On
OPOC "geniiops"
OPE NEW
O 1 "OCM1" 0.0 "_Dy tol"
O 2 "OCM2" 0.0 "_2.1 Dy"
O 3 "OCM3" 0.0 "_2.8 Dy"
O 4 "OCM4" 0.0 "_3 Dy"
O 5 "OCM5" 0.0 "_4 Dy"
O 6 "OCM6" 0.0 "_up Dy/3"
O 7 "OCM7" 0.0 "_3.2 up Dy"
O 8 "OCM8" 0.0 "_Fnb tol"
O 9 "OCM9/OCM8" 1.0 "Fnb diff"
O 10 "OCM10/OCM4" 1.0 "Focus diff"
O 11 "OCM11/OCM1" 1.0 "Axial DY"
O 12 "OCM12/OCM6" 1.0 "Axial OPD"
O 13 "OCM13/OCM6" 1.0 "Axial DMD"
O 14 "OCM14" 0.0 "_0.7 Dstol"
O 15 "OCM15" 0.0 "_0.7 Dist"
O 16 "OCM15/OCM14" 1.0 "0.7 Dist"
O 17 "OCM17/OCM2" 1.0 "0.7 YFS"
O 18 "OCM18/OCM2" 1.0 "0.7 XFS"
O 19 "OCM19/OCM7" 1.0 "0.7 Coma"
O 20 "OCM20/OCM3" 1.0 "0.7 DY U"
O 21 "OCM21/OCM6" 1.0 "0.7 OPD U"
O 22 "OCM22/OCM6" 1.0 "0.7 DMD U"
O 23 "OCM23/OCM3" 1.0 "0.7 DY L"
O 24 "OCM24/OCM6" 1.0 "0.7 OPD L"
O 25 "OCM25/OCM6" 1.0 "0.7 DMD L"
O 26 "OCM26/OCM3" 1.0 "0.7 Sag DX"
O 27 "OCM27/OCM1" 1.0 "0.7 Sag DY"
O 28 "OCM28/OCM6" 1.0 ".7 Sag OPD"
O 29 "OCM29" 0.0 "_1.0 Dstol"
O 30 "OCM30" 0.0 "_1.0 Dist"
O 31 "OCM30/OCM29" 1.0 "1.0 Dist"
O 32 "OCM32/OCM4" 1.0 "1.0 YFS"
O 33 "OCM33/OCM1" 1.0 "1.0 XFS"
O 34 "OCM34/OCM7" 1.0 "1.0 Coma"
O 35 "OCM35/OCM5" 1.0 "1.0 DY U"
O 36 "OCM36/OCM6" 1.0 "1.0 OPD U"
O 37 "OCM37/OCM6" 1.0 "1.0 DMD U"
O 38 "OCM38/OCM5" 1.0 "1.0 DY L"
O 39 "OCM39/OCM6" 1.0 "1.0 OPD L"
O 40 "OCM40/OCM6" 1.0 "1.0 DMD L"
O 41 "OCM41/OCM5" 1.0 "1.0 Sag DX"
O 42 "OCM42/OCM1" 1.0 "1.0 Sag DY"
O 43 "OCM43/OCM6" 1.0 "1 Sag OPD"
O 44 "OCM44" 0.0 "_f1_fymax"
O 45 "OCM45" 0.0 "_f2_fymin"
O 46 "OCM46" 0.0 "_f2_fymax"
O 47 "OCM47" 0.0 "_f2_fx"
O 48 "OCM48" 0.0 "_f3_fymin"
O 49 "OCM49" 0.0 "_f3_fymax"
O 50 "OCM50" 0.0 "_f3_fx"
END
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