TEST AND EVALUATION REPORT P. I. STAGE RETICLES

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04560A007400010020-2
• Release Decision: RIPPUB
• Original Classification: U
• Document Page Count: 12
• Document Creation Date: December 28, 2016
• Document Release Date: July 6, 2000
• Sequence Number: 20
• Publication Date: February 1, 1974
• Content Type: REPORT

Approved For Release 2001/08/13 : CIA-RDP78BO456OA007400010020-2
FOR OFFICIAL USE ONLY
TECHNICAL
PUBLICATION
NATIONAL PHOTOGRAPHIC
INTERPRETATION CENTER
TEST AND EVALUATION REPORT
P. I. STAGE RETICLES
N P I C/R -09/74
FEBRUARY 1974
Approved For Release 2001/08/13 : CIA-RDP78BO456OA007400010020-2
 Approved For Release 2001/08/13 : CIA-RDP78B04560A007400010020-
FOR OFFICIAL USE ONLY IPIC R-09/7)4
TECHNICAL PUBLICATION
TEST AND EVALUATION REPORT
P. 1. STAGE RETICLES
FEBRUARY 1974
Comments and queries regarding this report are welcome.
They may be directed
NPIC/TSG/ESD/TEB, Code 143, Ext. 3681
NATIONAL PHOTOGRAPHIC INTERPRETATION CENTER
Approved For ReleagSPFo6 d lA P b'4y560A007400010020-2
 Approved For ReleaRQMOQ/IUPWIA&A -Abid4'960A007400010( 1/R-09/7+
1. INTRODUCTION
2. DESCRIPTION
3. TEST DETAILS
4. OPERATIONAL SUITABILITY
5. CONCLUSIONS
DISTRIBUTION LIST
FIGURE 1. Enlarged Photograph of the P.I. Stage
Reticle
Page
iii
Reverse side blank
Approved For Release-20 O~Q8/13fAC1 76 4560A007400010020-2
 Approved For ReleagOB0W iAbIAII*bP O 'S6OA007400010 b R'-09/7+
Figure 1. Enlarged Photograph of the P.I. Stage Reticle
1
Approved For Rele qo8 HV? LCle-i?Paft0 560A007400010020-2
 Approved For Reid 26 RI HALdI C 14560A00740001I} -2-09/74
Five P.I. stage reticles all essentially identical and
manufactured to meet Center development objectives, were
tested in May 1973. Test Report TSG/ESD/TEB-22/73 describes
the results of the earlier test program.
In brief, the report concluded that the P.I. stage reticles
met all design objectives except for one major one. "The
graduation marks of the reticles are not in focus when they
are used in conjunction with in-focus imagery. This condition,
in particular, exists when the reticles are used with higher
(60-120X) microscope magnifications."
Recently, four additional P.I. stage reticles were manu-
factured with two changes in design from the earlier model.
This report describes the Test and Evaluation Branch's (TEB/
ESD/TSG/NPIC) evaluation of these latest reticles.
2001/08/13 Approved For ReFOR, OFFICIAL CIA- ONLY 4560A007400010020-2
 Approved For Rele W 6&kW4h IC MPM13Y4560A00740001
N
U
-09/74
The P.I. stage reticle (Figure 1) is a relatively in-
expensive mensuration device designed for use by photointer-
preters. Basically, it consists of two precisely (positional
accuracy +1 micron) graduated scales, one in metric units
(0.02 mm smallest graduation) and the other in English units
(0.0001 ft. smallest graduation). The scales are abrasive-
resistant chrome deposited on optically polished glass, 21 mm
in diameter. To facilitate handling the glass reticle, it is
mounted in the center of a transparent 90 mm diameter, 3 mm
thick plastic holder. The reticle is positioned on top of
photo imagery and under viewing microscopes for making measure-
ments.
Changes Made by Manufacturer
? Protective Coating on Reticle Holder - The reticle
holders are made of clear plastic "photoplast" material having
a photographic emulsion on one side. Concentric circles are
photographically printed on the holder to assist the photo-
interpreter in centering the reticle. The emulsion of the
photoplast part in the first samples of the P.I. stage reticle
was protected by a thin coating of silver lacquer which the
manufacturer centrifuged on the bottom surface of the holders.
This increased wear resistance.
The reticle holders on the latest samples are reported to
have been coated with silicon monoxide by a vaporization process.
The reason given for the change was that this would provide
a more'uniform surface flatness.
? Reticle Mountin - Samples tested in May 1973 had
reticles recessed to a specified 0.001 inch (+.0005, -.0000)
above the bottom surface of the reticle holders.
Of the latest samples submitted for testing, two were
reported to be recessed 0.0005 inch and the other two mounted
flush (0.0000 inch) with the holder surface.
Prior to TEB testing, the holders were marked for iden-
tification. Holders No. 1 and 2 have recessed reticles,
whereas Nos. 3 and 4 have flush-mounted reticles.
Approved For ReI 2a-FU LC1 -K0 4560A007400010020-2
 Approved For Releg6W:#,~Cb('4560A00740001EB1SZI-09/7+
Reticle Line Quality
Each reticle was examined at 200X magnification for line
smoothness and breaks. Three reticles had no defects, but No.
2 had minor breaks in graduation lines.
Reticle Mounting
Test Procedure - A B$L Dynazoom microscope was used at
200X magnification to provide a minimum depth of focus measur-
ing device. Each reticle and holder was placed under the
microscope and on top of satin-finish ground glass. The
ground glass was brought into focus and the focus position
recorded. One end of the measuring scale was then brought
into focus and the new focus position (in microns) recorded.
This procedure was repeated for each end of the millimeter
scale and foot scale. Focus readings were made on four dif-
ferent occasions over a 2-day period. These readings were then
averaged.
By this procedure, the position of each reticle in its
holder with respect to a flat surface was determined.
Reticle tilt was measured by taking the difference in
average focus readings from one end of each scale to the other.
The height of each reticle center above the flat surface
was calculated by averaging all "focus difference" measure-
ments made of that reticle. For reporting, this is called
the reticle recess. It possibly includes some movement away
from the surface because of nonflatness of the reticle holder.
Test Results - Reticle tilt is calculated to be less
than minute of angle in most cases and less than 2 minutes
in the worst case. The "focus shift" needed from one end of
a reticle scale to the other was no greater than 3 microns in
most cases and 7 microns at worst. The millimeter scale is
10 mm long; the foot scale is approximately 12 mm.
Approved For Release 2001/08/13 : CIA-RDP78BO456OA007400010020-2
FOR OFFICIAL USE ONLY
 Approved For ReleFa26WW/41*I-Ci flPhbY4560A00740001vvzi}' z -09/7+
Reticle No.
Measured Distance
Specified by
Manufacturer
Microns
Inch
1
25
0.00086
0.0005
2
19
0.00065
0.0005
3
13.2
0.00045
0.0000
4
11.8
0.00041
0.0000
Discussion - For comparison, four of the five reticles
teste in May 1973 were recessed approximately 61 microns
(0.0021 inch) and the other one 93 microns (0.0032 inch).
The P.I. stage reticle is likely to be used with the B&L
Zoom 240 microscope. The theoretical depth of field of this
instrument at 120X magnification is 28 microns (0.0011 inch).
Therefore, any reticle recessed more than half that amount, 14
microns, is likely to be out of focus.
Reticle Focus Versus Photographic Imagery
Each P.I. stage reticle was positioned over selected
targets on aerial film imagery while viewing with a Zoom 240
microscope. Various magnifications up to 120X were used.
At magnifications up to 90X, no shift in focus is necessary
to keep both the photographic and reticle images in sharp focus
with either reticle sample.
At 120X magnification there is a need for a focus change
between photographic imagery and the recessed reticles. This
is because the line width of the reticle graduations marks
enlarge in their partially out-of-focus condition. This con-
dition was not evident when using the flush-mounted reticle
samples.
Approved For Relea,Sb fOQ,1 MAElt-jg~PbW4560A007400010020-2
FFI
 Approved For Ref "2 iALC kV'64560A00740001%'b x'09/74
4. OPERATIONAL SUITABILITY
One recessed and one flush-mounted reticle sample were
o erationall used b photointerpreters in IEG for 2 weeks,
STATINTL
Verbal reports from these activities indicate that the
latest samples of the P.I. stage reticle are well liked. IEG
presently lacks the 120X capability for their Zoom 240 micro-
scopes; therefore, tests they made were at 6OX magnification.
At this magnification both reticle samples were satisfactory.
Their preference, however, is for the flush-mounted reticles.
This is because they anticipate soon having the 120X Zoom 240
capability with its smaller depth of field.
The two reticles operationally used by IEG were examined
for possible wear of the reticle lines and concentric circular
lines on their holders. There was no evidence of damage after
2 weeks of photointerpreter use.
Approved For Release 2001/08/13 : CIA-RDP78B04560A007400010020-2
FOR OFFICIAL USE ONLY
 Approved For ReleY CW4'/E>iflJAICIfA bl4 560A007400016WJ&12R-09/74
Both the recessed and flush-mounted samples of the P.I.
stage reticle submitted for testing are satisfactory for
operational use with microscopes up to 90X magnification. At
higher magnifications, the flush-mounted samples were superior
in performance. This is because of the very limited depth of
field at higher magnifications and the need to keep both film
imagery and reticle graduations in focus simultaneously.
The new vacuum-deposited silicon monoxide protective
coating on the reticle holders is expected to satisfactorily
inhibit surface wear because no evidence of damage was detect-
able after 7 weeks of use.
All of the design objectives for the P.I. stage reticle
have been met.
Approved For Rele 08' f/l?ALCI1RP3M?f560A007400010020-2
 Approved For ReIF A 4 & L & 6WW64560A0074000
Distribution List
Activity
NPIC/TSG/TOS (Thru Ch/TSG)
NPIC/TSG/ESD
NPIC/PSG/RERD/PB
NPIC/PSG/R&RD Library
NPIC/PS/PAB
NPIC/IEG/TPS
ODEE/IRDD
OD&E/ IRDD
STATINTL DIA/DI-8
Arm SPA
STATINTL
ffic g O9/7)4.
No. of Copies
Approved For Relp;U 26ffffl ~ (MfD&~t~94560A007400010020-2
 Approved For Releas(FM lUff ACI1L1$ S190456OA007400010020-2
Approved For Release ~1 8k~ ikllbWBT&Bp4560A007400010020-2