Night vision Radiometer/Photometer/Colourimeter
The
NviSpot Night Vision Radiometer/Photometer/Colourimeter is a
multipurpose instrument designed to meet the NVIS radiance light
measurement compatibility requirements of MIL-L-85762 for NVIS
applications, and also perform the conventional fast and accurate
luminance and colourimetric light measurements long associated with
the PR-1500 SpotMeter
It consists of a modified
Pritchard-type filtered photometer system with interchangeable
objective lenses and an internal calibration source. For NVIS
measurements it includes a proprietary filtered, extended-red gallium
arsenide photomultiplier tube with overload protection, threshold
detection and an NVIS-compatible digital display readout. Although
the NVISpot does not replace the requirement for a laboratory-grade spectro-radiometer
specified in the MIL Spec, it does provide a relatively inexpensive
and highly accurate means of light measurement for all phases of
production and control testing.
NVIS
radiance mode
For the Aviators Night
Vision Imaging System (NVIS) applications, the PR-1530AR includes a
special filter/detector combination whose transmission curve
precisely matches the NVIS relative response in MIL-L-85762.
When operated in the NVIS
Mode, the NviSpot display reads out in NVIS Radiance (NRa or NRb)
units. Relative colourimetric filters are optionally available for
evaluating the colour of the device under test, i.e., Green A, Green
B, Yellow and Red.
The digital display of the
PR-1530ARis specifically NVIS-filtered to eliminate any inaccuracy
it's own light output might introduce into the test results.
A very useful feature in
the NVIS mode is the user adjustable threshold detection. An audible
tone is generated when the display reading exceeds the maximum value
of NR units set by the user for the device and/or test. This feature
enables the PR-1530AR to be used as a rapid GO/NO-GO test instrument
for on-line inspection of a series of devices that share a common NR
upper limit, for instance 1.7 x10-10 NR units. An optional fiber
optic probe, the LP-15, further enhances the GO/NO-GO testing feature.
The calibration accuracy
required by the MIL-L-85762 us assured through the inclusion of an
extremely stable internal reference standard. Correct calibration can
be instantly verified at any time without the need for any external
calibration sources or relying upon some vague factory calibration.
And to prevent the accidental damage to the sensitive photodetector,
a resettable automatic overload protection circuit has been designed
into the PR-1530AR.
Lens accessories are
available to modify the field coverage of the PR-1530AR over the
entire range of devices likely to be measured for NVIS requirements.
A uniquely shaped fiber optic probe, the LP-15, is available for
measurements best suited to its field coverage capabilities. Analog
output is included, and a BCD output is optionally available to
permit interfacing to a host computer or data-logger.
Luminance/Colourimeter
modes
While the NviSpot is
designed primarily for measurements relating to MIL-L-85762, it also
functions as an extremely sensitive luminance and colourimetric
measuring instrument. In this mode it acts as a high performance PR-1500
SpotMeter. Many of the standard PR-1500 accessories can be used with
the NviSpot to extend its versatility to include the features
currently available with the PR-1500 SpotMeter.
Features
-
Direct NVIS(NRa, NRb)
measurements and GO/NO-GO testing of GreenA, GreenB, Yellow or Red
panels or filters
- Adjustable
sensitivity threshold (NR) units with beeper
- Stand-alone,
high performance, photopically corrected Filter Photometer.
- Resettable
detector overload protection with beeper
- Illuminance/Irradiance
measurements(with optional accessories)
- Relative
colorimetric measurements of NVIS devices (optional)
- Capabilities
of the PR-1500 SpotMeter
- Internal
calibration source
- NVIS
compatible readout
- Wide
range of optical accessories
- Dual
sensitivity ranges for optimum performance
Specifications
Measuring
field aperture |
3 Degrees |
Spot size* |
3° to
0.003 inches. (0.016 inches with the 7X standard objective lens)(See Field
Coverage and Relative Sensitivity table) |
Spectral
response(NVIS filtered) |
per
MIL-L-85762(450 nm to 930 nm) Consult factory for Class A, Class B or both |
Spectral response(photopic) |
380 nm to
760 nm |
Photometric
Accuracy |
±5% of
full scale or ±1 digit (whichever is greater) |
Readout |
3½
digits green LED display (filtered for NVIS compatibility) |
Output signals |
0-2 volts
analog standard; BCD parallel optional |
Sensitivity |
10-4
to 104
footLamberts, 10-11
to 10-3
NR units. |
Power |
117±13volts,
50 to 400Hz, 5 watts max(230±40volts available on request) |
Size |
12½
inches(31.3 cm) x 6¼ inches(15.9 cm) high x 5¾ inches(14.6 cm) |
Weight |
8½
pounds(3.6 Kg.) |
Field
Coverage and Relative Sensitivity
Lens/*Optical
Accessory |
Lens-to-subject
distance |
Nominal
Field Coverage |
Relative**
Sensitivity Multiplier |
MS-75 (1X) |
1.75 in.
(44.5 mm)
to infinity |
0.114 in.
(2.90 mm)
(at 1.75 in.) |
1. |
MS-1X |
3.8 in.
(96.5 mm) |
0.114 in.
(2.90 mm) |
1. |
MS-2.5X |
1.76 in.
(44.7 mm) |
0.046 in.
(1.17 mm) |
1. |
MS-77(3X) |
4.1 in.
(104 mm) |
0.038 in.
(0.97 mm) |
1. |
MS-5X |
1.11 in.
(28.2 mm) |
0.023 in.
(0.58 mm) |
1. |
MS-7X
(Standard Objective) |
0.7 in.
(17.8 mm) |
0.016 in.
(0.41 mm) |
1. |
MS-10X |
0.61 in.
(15.5 mm) |
0.011 in.
(0.28 mm) |
10. |
MS-25X |
0.6 in.
(15.24 mm) |
0.0045 in.
(0.114 mm) |
100. |
MS-50X |
0.6 in. |
0.0023 in.
(0.058 mm) |
100. |
LP-15 |
Contact |
0.015 x
0.090 in.
(0.38 x
2.29 mm) |
10. |
*All lenses
are fixed focus except the MS-55 lens. Contact factory for lenses of
other field coverages.
**A
relative sensitivity multiplier of 10 means the PR-1530AR is 1/10 as
sensitive with the accessory as with the MS-55 lens
|