Operating Instructions

2
You can understand what diffused light is by considering two light bulbs.
One light bulb has a clear glass envelope, and one is frosted. The clear light
bulb appears to be brighter when you look at it, but it is also glaring and
gives off uneven light coverage and causes shadows, so it is not as good
for lighting use in most situations. The frosted bulb appears to our eyes as a
round glowing orb of homogenous light. The frosted coating causes the light
to disperse and scatter so that it illuminates in a more even way, providing
better coverage and less shadows. (Note: This is not to say that a frosted
incandescent bulb, by itself, is a good light source when you use your
chronograph indoors. It is not.)
On bright sunny days, you should always use the white plastic diffuser
screens so that the light that the chronograph sensors see from above is
homogenous and scattered. This will greatly reduce errors in velocities and
missed detection.
On an overcast day, it is generally better to remove the diffusers. This is
because the clouds act as diffusers and so no further diffusion is needed;
rather in this case it is more advantageous to allow more light into the
chronograph.
Some Common Conditions that May Cause Problems
You can encounter a wide variety of lighting conditions if you use your
chronograph outside. The following are some things to look out for:
Reections
On sunny days shiny, light colored or smooth projectiles may cause
reections which can induce velocity errors. Be sure to use your diffusers
on sunny days. However, this may not be enough, by itself, to correct the
problem.
You can move the chronograph to a location in the eld of a shadow cast
by a building or an opaque wall. Make sure the sensors have a clear view
of the sky but the chronograph itself is within the shadow. An alternate
method for this is to use shields taped on the sides of the guide rods to
create the shadow. Be sure to use cardboard or something similar that will
not cause any problems with ricochets. This will eliminate reections from
direct sunlight, while still assuring that the chronograph has a direct view
of the sky. If you are having problems with reections from shiny bullets or
arrows, another remedy you can try is to take a black marker and color your
projectiles with it. This will greatly reduce glare and may be needed if you
have to use the chronograph in less than ideal lighting conditions.