ADDENDUM TO CONTRACT(Sanitized)MICRO-STEREOSCOPE AND BINOCULAR MICROSCOPE COMBINATION

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A002300090005-3
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 5
• Document Creation Date: December 28, 2016
• Document Release Date: June 11, 2001
• Sequence Number: 5
• Publication Date: November 21, 1966
• Content Type: CONT

Approved For Release 2001/8A?~l3r jgFIK8LB0474FA002300090005-3 21 NOV 1966
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Micro-Stereoscope And Binocular Microscope Combination
The purpose of this addendum is to suggest some possible alternate
solutions to increase the resolving power, cont ast, and secondary
color in the present design.
There are three areas which we would consider investigating, and
which would yield the most results in the shortest period with mi-
nimal cost.
The following outline describes the areas, time, and cost figures for
each area. These figures are estimated with some degree of accuracy,
however, they may vary in actual cost by a fact r of ?. 10%.
Declass Review by NIMA / DoD
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CONFIDENTIAL
1. Optimization of the zoom portion of the system.
As can be observed on the aberration plots, (variations in coma,
as a function of zoom positions, limits the offf-axis resolving power.
By changing the design of the zooming portion, the full field high
contrast resolving power at the 1X zoom position for all objectives
could be improved by a factor of 2 times.
Cost for this portion would run:
2. Eyepiece design.
Since existing 10X wide field eyepieces have been designed to function
best under particular operating conditions, it is felt that the instru-
ment could be closer to an optimum design, using specially designed
eyepieces. The high contrast resolving pow r could have an expected
increase of about 10 to 20 percent at the edg of the field while main-
taining adequate eye relief for use with eyeg.asses. In addition, since
the exit pupil of the system is in a rigidly constant position, even while
changing magnification, it would be desirable to maintain this constant
position for all field points. This can be achieved by carefully cor-
recting the spheric aberration of the pupil. While this correction does
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not add to the resolving power of the instrument, it does decrease
operator fatigue over extended periods of use. Many eyepieces have
kidney-shaped dark patches in the field and re uire movement of the
head in order to see the total field, a conditio which certainly must
cause considerable eye fatigue to the user. Te cost of designing a
new lOX wide field eyepiece would be:
The additional cost of manufacturing one set o eyepieces for the proto-
type would run approximately
3. Reduction of secondary color.
The limiting axial image defect of the system is secondary chromatic
aberration. This results in a purplish imagin of black objects with
a greenish yellow background haze. This chromatic condition could
have considerable effect on the imaging of low contrast targets as can
be witnessed by the use of color filters with an ordinary achromatic
microscope. In a non-quantitative manner, the effect can also be seen
as a background haze surrounding a bright spo and thus affecting fine
structured low contrast objects. Although it is difficult to predict the
change in MLTF at higher frequencies of low contrast targets resulting
from a 2X reduction in secondary color, an increase of approximately
10 percent might be expected.
CONFIDENTIAL
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Reduction of secondary color is a rather tedious task requiring care-
ful glass choice along with large amounts of computing. Considerable
reduction could certainly be achieved by the se of a mineral flourite,
but this material has a cost of approximate) 20 times the average op-
tical glass. Use of other materials, such as short flints and phosphate
crowns, might increase the cost of glass by factor of two and would
not affect the total cost of the instrument by ny great degree.
The change in design to reduce secondary co or would have the following
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