DESIGN OBJECTIVES TWIN LIGHT SOURCE STEREOSCOPE LIGHT TABLE

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A002400070008-1
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 6
• Document Creation Date: December 28, 2016
• Document Release Date: May 16, 2001
• Sequence Number: 8
• Publication Date: September 10, 1964
• Content Type: REQ

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10 September 1964
DESIGN OBJECTIVES
TWIN LIGHT SOURCE STEREOSCOPE LIGHT TABLE
GENERAL:
1. Light tables which are currently used and which have a support
for a stereoscope: (1) do not have a sufficiently large illuminated
viewing area, and (2) cannot be tilted to positions convenient for the
user.
2. The proposed light table (see sketch attached as Enclosure l)
must be capable of tilting through a range of angles. It must also have
an adequate viewing area divided, by a removable partition, into two
independent light sources for stereo viewing of positives with differing
densities or with differing scales.
3. To be used under normal office working conditions, the table
will not ordinarily be subjected to extremes in temperature or to
excessive shock or vibrations.
4. For normal use, the table will not have reel brackets; but,
if it appears practicable, the design should provide for dual reel
brackets which could be mounted at a later date. The reference is to a
type of dual reel bracket (T-2-5) manufactured by the Richards Corpora-
tion, Arlington, Virginia; or an equivalent. If it is practical. to use
these specific brackets, they will be supplied as government-furnished
equipment.
5. Proposal must include the following:
a. Cost and delivery time for one prototype.
b. Cost and delivery time for three production models
after the prototype has been approved.
c. Cost and delivery time for one set of directly
reproducible manufacturing drawings and specifications.
6. If the contract will cover a period of more than 90 days, we
require monthly progress reports, which must also state the percentage
of funds expended to that date and the percentage of work completed.
Declass Review by NIMA / DoD
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All proposals must be accompanied by a summary, (using the format
7?
shown in Enclosure 2) of the proposed table's characteristics.
ELECTRICAL:
1. Power Source:
a. The light table shall operate on a nominal 117-volt,
50-60 cycle alternating current supply.
b. The light table shall be equipped with a 3-wire power
cord, not less than six feet long, terminated at one end with a
? ? Power Connector (made by the APM-Hexseal Corporation,
Reflex Safety or its equivalent. The
41 Honeck Street, Englewood, New Jersey),
other end shall be terminated within the lighablet all be
securely mounted to the frame of the (ground) conductor in the power cord shall be grounded to the
metal frame of the light table.
c. Separate on-off switches shall operate each light source,
sity
and it is permissible to inioh~orshouldebewbuiltsinnto indicatenwhen
controls. Separate pilot 1 g
the equipment has been turned on.
2. Light Sources:
a. The two light sources shall be high-intensity, light grids.
The grids shall be designed so that they are interchangeable and can
unskilled personnel using a minimum of the
be replaced by relatively
more common hand tools. The grids must not be potted or encapsulated.
b. The maximum intensity of each light source ust be
liless
than 1500 foot-lamberts measured at the working surface.
sources will be sufficiently diffused: havingisoscore t alo10%
variation in intensity as the working surface line which is perpendicular to the light grids. The intensity of
the two light sources shall be independently variable from
and full
intensity to less than one-tenth of the full. intensity
noticeable flicker at any level of intensity. Variation in intensity
shall be effected with wighindcomfortablenreach ofuthedoperatorrear
of the light table b
from the front.
c. After extended use (6-8 hours), the temperature of the light t table must not rise to the level where
prebentmlightcfrom shiningo
use. Any air vents must
into the operator's eyes or the eyes of anyone in proximity.
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MECHANICAL:
1. General:
a. The overall dimensions of the light table shallconsi be kept
to a minimum to avoid wasting work space, but shall be stent
design principles. The height of the light table will
with good person in a sitting
be governed by the eye level of an average p e is used on the
position when a B&L Model II zoom 70onterwoscong surface on the f-
light table, which itself is placed
30 inches above the floor. Thewlightwtable susteoscope or
sufficient rigidity to resist warping when,
microscope mounted on it, it is hand-carried from one desk to
another.
2. Viewing Stage:
a. The lighted area shall be approximately 10 inches in
width by 6 inches in depth. The total viewing area will be
divided into two independently illuminated areas -- each approxi-
mately 5 inches wide by 6 inches deep.
b. The illumination r the twoTheareas
diffuserbshould1bedaby
separate but identical light grids.
single piece of opal plastic but the stage must be constructed
en
of a single piece two
of glass. A light baffle, separating grids, must be included to prevent light from spilling betwethe
we
the two grid areas. This baffle must be easily e toive
prevent unbalanced illumination of the two halves of a posi
in monoscopic viewing.
c. The upper, or working, surface of this glass shall
protrude above the surrounding area by at least 1/16 of an
inch. The metal surface immediately surrounding the viewing
stage shall contain holes for the insertion of stage spring
clips. These holes will have the same diameter, depth and spacing as is used on the Bausch & Lomb Zoom 70 Trans-
illumination illumination Base (part of B&L Catalog Number 53-70-01-01)
so that the B&L spring stage clips may be used without
modification.
3. Tilting of the Light Table:
a. The light table, with the microscope attaac ed, so llhe
be capable of being tilted about an axis along the front front of
light table (see Enclosure 1). The tilting shall p
lace the viewing stage in the horizontal position
ope to place to the horizontal. This tilting
or up ptor to a maximum angle of ~+5
u
shall be accomplished in 5? increments of tilt and simple ratchet
and pawl, or similar device, will be used to hold the table in
the tilted position.
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b. The tilting mechanism will be of the positive lock
type; that is, either the ratchet or the pawl shall be spring
loaded so the table, if jarred, will not fall into the hori-
zontal position.
4. Microscope Mount:
a. In the design and construction of this light table,
provisions must be made enabling the user to mount a Bausch &
Lomb Model II Zoom 70 Stereoscope, a Wild Model M-5 Stereoscope,
or -- by the fabrication of a simple adapter -- to mount any
similar type of stereoscope or microscope of approximate weight
and size on the light table. Microscope mounts shall be able
to be changed by the use of common hand tools or, preferably,
by the use of thumb screws.
b. It will be necessary to maintain alignment of the stereo-
scope's optical axis to within 10 minutes of arc of a right angle
to the viewing stage. Provisions must be made for using common
hand tools to provide this degree of alignment, regardless of the
type of stereoscope or microscope in use.
c. The stereoscope supports must be sufficiently rigid,
without "play", to hold and maintain the degree of alignment
(10 minutes of arc) stated in paragraph 4b, above. Allowing
for the auxiliary lenses of any stereoscope or microscope used,
the basic mount must be capable of vertical. movement over the
viewing area. As an example: the B&L Zoom 70 Stereoscope is
used with 0.5X and 2.OX auxiliary lenses for binocular viewing
and with a rhomboid for stereo viewing. A gross positioning
must be made for approximate focusing with a particular auxiliary
lens; then, fine adjustment (normally part of the supporting
arm of the stereoscope or microscope) will be used to bring the
image into sharp focus.
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+5 *MAX.
POWER SUPPLY, CONTROLS, #7 ,)
THIN AS POS-SIBI.F.
This drawing is included only to convey the
basic design of the Twin Light Source Light
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Summary Sheet: Proposal for a Twin Light Source Stereoscope Light Table
1. Overall dimensions: height - inches
width - inches
depth - inches
2. Weight (less stereoscope and support) pounds.
3. Intensity of light source (measured at the working surface).
a. Intensity control at maximum foot-lamberts.
b. Intensity control at minimum foot-lamberts.
c. Variation across the grid - maximum
minimum
Max-Min X 100
Percent variation = Maximum
4. Cost and Delivery Time.
Cost Delivery Time*
a. One prototype
b. Three production models
c. One set each of directly
reproducible drawings and
specifications.
* After receipt of contract
Enclosure No. 2
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