Amount of Light (Lambet / Lux unit ) required on 10M target

[dsaptarshi]

Hello Everyone,

Can someone guide me about how much light is required on target for 10M Air rifle? I have been looking for this information on forum but not found any information on this. Is there any standard that is being followed on international competition? I understand that the target should be bright enough so that it can be viewed clearly from 33feet , but is there any scale like lambert or lux unit ,through which I can judge I have enough light on my target and its not too bright or dim as per standard ISSF rules.

I appreciate any help on the above.

Regards
Datta

[David Levene]

You might find that the attached extract from the ISSF rules answers your question.

[dsaptarshi]

Thanks a lot David, I really appreciate your help and I got the answer I was looking for.

[guidolastra]

For a home range (I assume this is the case), how to get such lighting, what type of light source (bulbs, etc...) do you think should be used ? I have the same problem, my range is dark.

[GCSInc]

First buy yourself a Light Meter. It is the only way to accurately measure the light. http://www.calright.com/pd_534.aspx $49.00

Then study the Technical Issues.
http://www.reliabilitydirect.com/RDISto ... 0Facts.pdf

My research shows that a 500 watt Halogen Shop light needs to be 7 feet (about 2 meters) or less to the target to illuminate it to 1000 lumens. It would need to be about 4 - 5 feet (aprox 1.5 meters) to make 1500 lumens. This will get you in the ball park. For three position Air Rifle, the light should be 18 - 24 inches off the floor (about even with kneeling) or you might want to use multiple lights (or move them) for each position.

Best Regards,

Roy McClain
www.OleMillRange.org

[Spencer]

500W sounds like overkill when an R80 75W reflector light at 300-400mm (adjust the set up with a light meter) will give the needed light level on an ISSF 10m target - that's what is used at most of the World Cups

[robf]

500W sounds like overkill when an R80 75W reflector light at 300-400mm (adjust the set up with a light meter) will give the needed light level on an ISSF 10m target - that's what is used at most of the World Cups

Light intensity falls off inverse square over distance... so at 1unit of distance away you need 1x of light, at 2, you need 4x of light, and at 3, you need 9x.... so if you need 75w at .4m you actually need 2000w at 2m to get the same luminosity... 2m is 5x the distance away from the target that 0.4m is so 25x more light is needed... if wattage = light (assumed), that's where you end up.

[robf]

interesting that the doc doesn't specify colour temperature...

[Spencer]

Light intensity falls off inverse square over distance... so at 1unit of distance away you need 1x of light, at 2, you need 4x of light, and at 3, you need 9x.... so if you need 75w at .4m you actually need 2000w at 2m to get the same luminosity... 2m is 5x the distance away from the target that 0.4m is so 25x more light is needed... if wattage = light (assumed), that's where you end up.

So? Put the light closer - with a suitable pellet deflector!

I will never be accused of being the world's greatest greenie :), but less power, less weight, less heat, less $$$...

[GCSInc]

Spencer,

You are correct, to a point. If you're shooting a single bull target your tiny light works fine. If you're shooting a 3x20, Hanging 6ea AR 5/10s then you'll need more light across a larger area. We put a 500 watt light (20" off the floor) in the gap between each Target holder (for a given number of target holders, you'd need an extra light on each end to even out the light) and that covers all three target heights.

Best Regards,

Roy McClain

[Spencer]

I did put in "...the needed light level on an ISSF 10m target..."

[robf]

Light intensity falls off inverse square over distance... so at 1unit of distance away you need 1x of light, at 2, you need 4x of light, and at 3, you need 9x.... so if you need 75w at .4m you actually need 2000w at 2m to get the same luminosity... 2m is 5x the distance away from the target that 0.4m is so 25x more light is needed... if wattage = light (assumed), that's where you end up.

So? Put the light closer - with a suitable pellet deflector!

I will never be accused of being the world's greatest greenie :), but less power, less weight, less heat, less $$$...

I get your drift ;)