NEWFIRM Optics

This lists the physical dimensions of the NEWFIRM optical components and intercomponent spacings at fabrication temperature (293 K).  These are derived from the cold optical design.  These dimensions were used for all mechanical designn work on the optics mounts and the optical support structure.

The lens dimensions are as specified to the vendor.  The Lyot stop diameters are specifications for the design.  Recall that this is a toroidal aperture in a metal plate, hence the outer diameter (OD) and inner diameter (ID) dimensions.  The OD is slightly undersized and the ID slightly oversized with respect to the optical design.  This allows some tolerance for alignment of the instrument to the telescope.  

The detector size includes a 4mm allowance for dead space between active areas of the arrays.

A side view of the optical layout in included below the table for component identification.  Note that only one filter is shown.

 

  Diameter of
lens
Edge
Thickness
Center
Thickness
Distance Cass
Focus to 1st
Surface
Distance Cass
Focus to 2nd
Surface
Distance Z axis
to 1st Surface
Distance Z axis
to 2nd Surface
Distance
between lens surfaces
Cass Focus ---- ---- ---- 0 0     20
Lens 1 407.00 20.16719 70 20 90 0   776.7701
Lens 2 200.00 9.28938 38.1205 866.77009 904.89059 0   39.80216
Lens 3 198.00 26.8005 15.00004 944.69276 959.6928 0   57.52359
1st Filter 124.xx 5.xx 5.xx 1017.21639 1022.21639 0   9.7536
2nd Filter 117.xx 5.xx 5.xx 1031.96999 1036.96999 0   14.0565
Lyot stop OD
Lyot stop ID
98.0821h
47.0318h
1.016 1.016 1051.026504 1052.042504 0   1.90249
Lyot stop arms 7.32j              
Lens 4 140.00 18.7 14.00004 1053.945 1067.94504 0   35.29597
Lens 5 173.00 12.43944 50.15857 1103.24101 1153.39958 0   11.75334
Lens 6 183.00 16.68435 18.02253 1165.15292 1183.17545 0   90.21169c
Fold mirror 245.00 50.8 50.8 1273.4571a        
Horiz. Axis ----             90.34497d
Lens 7 200.00 18.095674 50.158574 1273.4571a ---- 90.34497 140.50354 115.5294g
Lens 8 165.00 60.48456 16.000046 1273.4571a ---- 256.032914 272.03296 20.12637e
Lens 8 seat 165.00 ---- ---- 1273.4571a ---- 282.56778b ----  
                9.59155f
Detector
plane
106.6 sq ---- ---- 1273.4571a ---- 292.15933 ----  

All dimensions noted are in millimeters.
aCenterline of lenses 7 and 8 and Detector
bFarthest lens seat from the Z axis
cDistance from lens 6 surface to fold mirror surface
dDistance from fold mirror surface to lens 7 first surface
eDistance from lens 8 second center vertex to detector plane
fDistance from lens 8 seat to detector plane
gDistance between lens 7 and lens 8 surfaces
hLyot stop aperture is a doughnut with central obstruction. Dimensions include deliberate under/oversizing of 0.127 mm for alignment tolerance.
jLyot spider arm thickness, allowing for optical blurring and ±1 deg rotational misalignment. The arms are at 45 deg to the cardinal points.

NEWFIRM Optical layout

NEWFIRM with Fused Silica field lens. Total warm length 1368.69 mm, largest distortion 1.3%, largest skew ray angle on filter 13.52 deg.

 

 

Updated on September 5, 2023, 12:52 pm