401' 344-68-16/ 

6;115 rk 

1. SCOPE: This procedure details the operations, accuracies, references, 

and establishes the sequence for the assembly and alignment of the double 

pivot, rhomboid arm scanner for the slide viewing system (SVS). Reference should be made to the optical specification for the rhomboid arms 

memos # 344-68-048 and 068. 

2. DESCRIPTION: The rhomboid arm scanner consists of two parts, each of 

which contains two parallel mirrors in the normal rhomboid configuration. 

Each part (arm) is free to rotate in precise bearing which are co-axial 

with the optical centerline through the rhomboid mirrors. The upper arm 

is attached of the frame, while the lower arm is attached to the other end 

of the upper arm, very much in the way a human arm is configured. Each 

arm also contains photographic lenses and other optical elements. The 

arm which is nearer the film (the lower arm) can be either of two interchangeable sets of mirrors and lenses in order to accommodate different 

scales (magnification) of the input stimulus material. These arms shall be 

referred to as the high or low step, interchangeable rhomboid. The arm 

which is mounted to the frame contains a 10:1 zoom lens and shall be 

referred to as the zoom rhomboid. The main bearing at the optical bench 

structure is the shoulder bearing and the mirror above it is the shoulder 

mirror. Because the useful life of the zoom lens is expected to be limited, 

the zoom mount module will be prealigned as described in a separate memo. 

The prime reference for the rhomboid alignment is the mechanical 

centerline of the shoulder bearings. Secondary references are the optical 

AC' rC centerline in the zoom rhomboid, the centerline of the (elbow) bearing 

'HANDLE VIA BYEMAN 

CONTROL SYSTEM ON Y 

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1111 11111 

5737/ — Me; ir 

NRO APPROVED FOR 

.5E.LIEASE 1 JULY 2015 

TO R. K. I ee DATE: 4 April 1968 

FROM: R. W. Dyer Page 1 of 6 

BYE 4S1.4 1258. 69 

SUBJECT: Rhomboid Alignment Procedure 

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between the two arms, the centerline of the X-Y drive coupling and the 

axis which is perpendicular to the input platen. The alignment of the 

shoulder bearing axis to the optical centerline of the vertical optical 

bench structure is also critical. However, it is expected that this 

alignment will be maintained by careful machining and is outside the 

scope of this procedure. 

Axial distances will be referenced to the arbitrary axial position of 

a special reticle located in the zoom lens focal plane, with the constraint 

that both the high and the low step, interchangeable arms must be "in 

focus" at the same input platen location. The interchangeable rhomboids 

will be prealigned on fixtures as described in a separate memo. 

3. SUMMARY - ALIGNMENT PROCEDURE: The alignment procedure uses 

standard optical tooling, special fixturing and prealigned elements in order 

to guarantee 150 micron (.006") registration between the optical axis 

and coordinates on the input stimulus. The zoom lens is prealigned as 

a module in anticiration of future maintenance requirements. The 

interchangeable rhomboid arms are also prealigned in order to achieve 

the tight tolerances which are required for interchangeability as well as 

achieving the 150 micron registration. 

The error budget for the 150 micron registration allows .002" errorbetween the optical axis and the elbow bearing centerline, .002" error 

between the optic axis and the X-Y drive attachment point, .002" error 

between the optic axis and the shoulder bearing centerline, and 10 arc 

minute difference between the direction of the optic axis into and out of 

each rhomboid arm. In addition, the two interchangeable arms must 

have a common focus, within .003", the lenses in the arm must be 

centered to each other within . 003", and each lens must be perpendicular 

to the optic axis within 15 arc minutes. 

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The alignment begins at the image plane behind the zoom lens, using 

reference reticle which is adjusted to coincide with the centerline of the 

shoulder bearing within . 0002". Then the mirrors in the upper arm are 

adjusted with special fixtures and the lenses installed. The zoom lens 

was prealigned so that the only adjustment is to fix the Z axis (focus) stop. 

The X, Y, Z, adjustments on the collimator are used to complete the 

alignment of the zoom rhomboid. The interchangeable rhomboid arms 

have also been prealigned are assembled to the zoom arm to allow 

adjustment of the X-Y drive connection. Any residual errors are 

corrected by fine adjustment of the zoom collimator and the zoom elbow 

mirror. 

4. EQUIPMENT: The alignment procedure is based on using certain standard 

and special items of tooling. 

4.1 Surface Plate (Vendor, Cat. # TBD) 

4.2 Box parallel, modified to simulate actual mounting per drawing #(TBD) 

of the rhomboid scanner on the optical bench structure. 

4.3 Alignment telescope, w/right angle eyepiece, bracket for vertical 

mounting, (Taylor-Hobson #112/636/638 Telescope, #112/568 Eyepiece 

Assembly # TBD Bracket). 

4.4 Special target stand for defining the optical axis of the zoom rhomboid 

frame per drawing #TBD. 

4.5 Adjustable trivet, mirror and target holder per drawing #TBD. 

4.6 Standard, silvered alignment target (Vendor, Cat. #TBD) 2 required. 

4.7 Special reticle target holder for use at elbow per drawing #TBD. 

4.8 Separate fixture for prealigning zoom stage module per assembly #TBD. 

See separate memo. 

HANDLE VIA BYEMAN 

CONTROL SYSTE 

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owy4. 9 Separate fixture for prealignment of interchangeable rhomboid. See 

pa ra )1.cmo. 

4.10 Special collimatoi mount with vertical pointing mirror per drawing #TBD. 

4.11 Alignment projection collimator. 

4.12 Special centering target for X-Y drive coupling. 

5. INITIAL SET-UP: 

5.1 Level surface plate to 1 arc minute. 

5.2 Secure box parallel to surface plate so that key axis and reference surface are 

square to surface plate to 1 arc minute (.0003 per inch). 

5.3 Adjust trivet (3. 5) so that mirror surface is parallel to surface plate 

within 10 arc seconds (i.e., .00025 variation across 5" scan of legs) 

adjust height from surface to within ±. 001 of nominal. 

5.4 Adjust alignment telescope square to trivet (3.5) within 10 arc seconds. 

6. ASSEMBLY AND ALIGNMENT: 

6.1 Assemble zoom rhomboid frame, shoulder bearing, and bearing mount to 

the box parallel, ensuring that bearing axis is parallel to the keyway. 

6.2 Mount shoulder mirror mount and adjustable zoom reticle, (assembly 

#TBD) to the zoom rhomboid frame. Position alignment telescope and stand 

over the reticle, focus telescope on reticle. 

6.3 Rotate the zoom rhomboid frame and adjust the reticle until the center is 

stationary within .0002". Position alignment telescope in X, Y coordinate 

(do not use micrometer) so that the reticle is superimposed on the 

telescope reticle. 

WM-Cr VIA BYEMAN 

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6.4 Install the special target stand on the collimator lens mounting pad. Set 

the alignment telescope for autocollimation and adjust the shoulder mirror 

until the return image is within 15 arc seconds. 

6.5 Focus on the target stand center. If required adjust the shoulder mirror 

mount by shimming until the centers are within . 003". 

6.6 Repeat 5.4, check 6.5. 

6.7 Install zoom elbow mirror, remove special target stand, position trivet 

under elbow, and set the alignment telescope for autocollimation. Adjust 

the elbow mirror until the return image is within 30 arc seconds. 

6.8 Attach special reticle target holder (3.7) to the kinematic flange on the 

elbow bearing, focus alignment scope. If re:,uire.d adjust zoom elbow 

mirror by shimming until the reticle appears centered within, .002v. 

6.9 Repeat 6.7 and check 6.8. 

6.10 Install prealigned zoom lens set at 50mm focal length and f/4. Position 

special collimator mount under elbow. Adjust the position of the.zoom 

lens focus stop so that the projected reticle pattern is focused on the 

zoom reticle. Confirm focus by going through zoom range. 

lock the focus stop to the rhomboid base. 

Permanently 

6.11 Install collimator lens, adjust focus until special reticle target is 

superimposed on zoom reticle. Adjust X, Y until the two reticles 

superimpose. Varify alignment by going through zoom. Secure the 

collimator adjustments. 

6.12 Remove special target reticle. Install high power step, interchangeable 

arm. (Prealigned). Set the rhomboid arms to correspond to the center of 

the input format. Position the trivet mount under wrist mirror. Swing 

arm out of the way and position alignment telescope over the trivet target, 

adjust t. 0015". Reposition rhomboids over target and carefully adjust to 

RANDLE VIA BYEMAN 

r ONTROL SYSTEM ONLY 

DIMSLCITik;5331. 
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±. 0005 alignment between the optic axis and the target by observing zoom 

reticle with a 10X loupe (zoom lens adjusted for maximum power). 

6.13 Install center target in X-Y drive mounting and focus alignment telescope. 

Adjust X-Y drive mount until target coincides ± .0005 with telescope reticle. 

Go through zoom range, checking for any image shifts. 

6.14 Reposition the trivet and the optic axis at each corner of the format as in 

6.12. Check the alignment by observing the X-Y drive mount target. 

Average any errors, install low power step and check registration, focus 

and zoom. 

7. ERROR CALIBRATION: The residual registration errors must be calibrated 

after complete assembly of the slide viewing system. The calibration procedures are not a part of this procedure. 

kp 

cc: J. D. Amara 

W. Britton 

K. Coughlin 

W. J. Gorman 

C. Ross 

R. Toone 

W. B. Wetherell 

)41()Sid.e2,1._ 

R. W. Dyer