Teacher Resource Notes for NVG
(Dennis L. Schmickley, The Boeing Company)
Dennis
Schmickley & Don McMahon visited Usery Park on 15 May 2000. We had several
sets of Night Vision Goggles (NVG): Class A & B, binocular & monocular.
It was not the best night for NVG but it was still spectacular. Moon was high
overhead and was more than 3/4 full. Thin overcast clouds both diffused the
moonlight and reflected Phoenix city lights. Although there was a direct view
of city lights in distance towards Apache Junction in the southeast, the desert
was mostly dark with a good NVG view to the east, north, west and southwest.
Usery Park offers a safe, secure environment that is close to Mesa. We found
that a laser pointer was an excellent tool to communicate where we wanted to
look at specific objects.
Overall
experience: Awesome, beautiful at night. NVG give a whole new perspective to
nighttime. Also, nature is quiet.
Staging
or assembly areas:
' Area 6' has good automobile
parking and has several ramadas and picnic tables for assembling. The lights can
be turned off for NVG use. The Pepsi machines are large illumination sources to
NVG; probably black plastic trash bag material could be taped over the machines
to dim the annoying lights.
Trails:
Students with NVG can easily walk the trails. With the NVG
focused to infinity (normal settings), the ground is generally in focus to
within 6 feet of the individual. One of the lens can be re-focused to the
ground directly at the individual's feet to allow near- focus with one eye and
far-focus with the other. Also, a flashlight with an appropriate blue filter
could be used. Students should stay on the trails and be vigilant for snakes;
the NVG gives the individual more confidence because all of the trail, bushes,
rocks, etc., can be seen. For longer hikes or large groups, the as halt roads
are available for NVG hiking.
Flashlights:
Students, teachers and chaperones should each be equipped with a
flashlight which has an appropriate NVG-compatible blue filter. This
light allows note taking, map reading, and general mobility that does not
interfere with the NVG exercises. We can find filter material sources for
purchase or donation to make flashlights. Another light which is available for
general use is a green Chem-Stick, which is a chemoluminescent light source.
Once it is activated, it cannot be turned off, but can be hidden in a pocket or
back pack.
Maps:
Maps of the park, trails and roads can allow for activity
planning and student learning. Map reading, orienting, points of the compass,
desert landmarks, finding north or Polaris. We might have a scavenger hunt
using light markers that can only be seen with NVG.
Outdoor
observation of desert:
The vision of seeing in the dark! The sounds of nature,
listening for animals. Observe nocturnal animals. Look at light/shadows of
desert plants. Observe that viewing a bright green image in the NVG decreases
one's visual dark- adaptation and produces a red-brown afterimage.
The NVG has only 400 field
of view. Since everyone will have a set of NVG there could be two techniques to
look for nocturnal animals:
1. Have all students look,
patiently, in a specific direction; the first one to see an animal can tell the
others where to look.
2. Have students look
toward different directions; the first one to see an animal can tell the others
which direction to look. However, birds and other animals move quickly, and
students may not have time to find it.
Evening nature studies:
Students could start out in
the afternoon. Have a picnic. Sun goes down; observe changes in desert -which
animals come out at night. Observe changes in vision, dark adaptation. Continue
into NVG experience.
Morning
nature studies:
Students
could begin at night with NVG. Sun comes up; observe changes- what animals
disappear or come out at dawn. Have a breakfast in the cool of the morning.
UV Light:
It would be interesting to
try a 'black light' to find scorpions. We can research which UV lamps might
work that don't affect the NVG.
Photography:
Mount an NVG to a camera
for night shots. Prints, slides, video.
Classroom
preparation:
Science studies of desert animals, plants. Human eye, retina, lens, tristimulis
response and color vision, dark adaptation, physiology, rods & cones,
resolution,
acuity, etc. Nocturnal animals;
coyotes, owls. Bats [radar].
Outdoor
demonstration of NVG and optics:
NVG performance-light amplification (gain), resolution, depth
perception, shadows, light sources, automatic gain control, field of view. NVG
can be used with starlight only up to full moon illumination.
Lighting sources- filtered
vs. unfiltered flashlights, IR LED as a flashlight (better with no moon) or a
beacon, red laser pointer, IR laser pointer. Direct view of city lights in
distance.
Students can report on any
other NVG observations they discover.
Students will be able to
observe for themselves if their cell phones, CD players, pagers, glowing
watches, etc. have non-compatible light sources.
Classroom
preparation:
Science studies of optics, electro-optics.
Theory of NVG image intensification (photons are converted to electrons,
electron signals are amplified, electrons are converted to photons), automatic
gain control.
Electromagnetic spectrum,
visible light, ultraviolet, infrared. Refraction, reflection, transmission.
Classroom
laboratory:
Darkroom
experiments in Flight Center. Preview to outdoor nighttime experience.
How to
use NVG, adjustments for focus (for
distance), diopter (for eye correction), interpupillary distance, eye relief.
Outdoor
observation of astronomy:
This can be quite dramatic when there is no moon -lots of stars!
Includes satellite observations, unaided and with NVG. Many aircraft in the
distance.
In
addition to using NVG, students can use binoculars or telescopes for associated
observations. Binoculars with large objective lens (50 mm) give good direct
view of the moon.
Classroom
preparation:
Science studies of galaxy, solar system, stars, planets, moon
phases. Space, spacecraft, satellites. Star charts. Naval Observatory charts
covering times for sunrise, sunset, moonrise, moonset, civil twilights,
nautical twilights, astronomical twilights, phases of the moon. Classroom
projects to prepare time charts for this Latitude & Longitude. Light,
brightness during day, brightness at night, sun & moon, reflections off
moon, stars.
Outdoor
demonstration of weather:
Clouds, no clouds, effect of clouds on ambient illumination.
Fog, haze, wind (and dust) which limit visibility.
Classroom
preparation:
Science studies of weather, atmosphere.
Infrared:
If Litton can also provide infrared (IR) devices then there are
other observations, experiments and experiences available. Thermal imagery hot
vs. cold.
Other
notes:
Tasks take longer at night.
Student groups get separated. Don't be rushed.
The duration of darkness
varies; winter nights are long; the summer has fewer hours for NVG experiences.
The desert is cool at night.
Very comfortable after hot days, but bring coats during the winter .
The desert is quiet. Great
place to have some peaceful moments. Listen to the desert. The desert is a
desert; bring water .
Prepared By: