How Much Light

[Bill Nesbitt]

Here's my situation. In my basement I have a bullet trap. I also have a Pro-Tach chronograph that I have used outdoors for 20 years. The Pro-Tach has been very reliable and has given consistant results as long as the screens are shaded.

It's cold outside.

How much and what kind of light do I need to chrono a few rounds in the basement. It's a standard unfinished basement with several 100 watt light bulbs scattered around.

I tried a couple of rounds of 22 long rifle but it wouldn't register anything.

Two cats were asleep on my bed just above the test site so I didn't try anything heavier.

[yoshidaex]

Bill,

as long as the lights aren't fluorescent. i recall reading somewhere our host and Rob used flashlights or some source of artificial light and with the chrono screen turned sideways they managed to get readings when the sun went down. You could try some drop lights right over the sensors and adjust accordingly till the chrono starts reading.

[shred]

I've had ok luck with a 500w Halogen bounced off the ceiling just above the chrono. A white target sitting on top of the screens would probably be even better. More light will give a better signal.

.

[Derek45]

Any light you are plugging into the 120VAC wall socket is turning on and off 60 times a second.

I think my old chrony had an optional kit that had DC lights.

DC lights are the way to go.

[yoshidaex]

heres one 110 volt lighting kit

heres another one

though these units may utilize some sort of AC to DC converter but any incandescent light should work

[mda]

MidwayUSA has a light kit you can mount on the screens.

http://www.midwayusa.com/eproductpage.exe/...leitemid=432880

Basically diffused incandescent light directly over the light sensors should work. Check out the article at the following link. Explains how a chrono works, basic do's and don'ts, and what to expect in the way of accuracy and % error.

http://www.pilkguns.com/Chrony.shtml

MDA

[yoshidaex]

awesome article! thanks!

[Blazer]

Great education for me. Thanks

[jmorris]

A few years ago, I was helping my brother in law with a science project and we ran out of daylight before we got finished. I used a setup similar to the one in the photo below. Just get a sheet of white cardboard and set the chronograph on the ends so it forms a loop, then place a 90 degree flash light to the side and your good to go.

[LPatterson]

I love the wealth of information available on this forum.

[SharonAnne9x23]

even though any light plug into 120V AC does cycle 60 times per second, the incandescent bulbs work by heating a metal filament and it remains hot, giving off continuous light that works well with a chronograph. We used 2-6" 'tube' style incandescent lights;one over each sensor. This allowed us to chrono indoors during inclement weather and after sunset.

[AZ38super]

I know when we used a chrono indoors for archery we had to diffuse the light as the chrono picks up the flicker in the bulbs no matter what type is used.

[FLL1911]

Removed. I did not see that someone already had posted something very similar. No need to say the same.

Edited December 17, 2008 by FLL1911