Is it possible to see objects at 600m distance in infrared

[Calconceptofnumber1]

Hi I am wondering if it is possible to see the full distance of a 600m beam from a 500lm torch with an infrared filter and infrared goggles?

 

[.Scott]

Do you really want to look at the beam - or an object at the end of the beam that is illuminated?
To look at the beam, you would have to project it into a mist (perhaps up into a cloud).

As long as you are not looking through fog, there should be no problem.
Of course, it will depend on the goggles and on the reflectivity of the scene.
I would review the specs on the goggles.

I have used a thermal IR scope that was capable of identifying a swimmer at 2 clicks.
That's not the same as your situation for a couple reasons:
1) Thermal IR does not require illumination.
2) The device was considerably larger than goggles (roughly an 18cm aperture).
3) It had a price tag well over $200K - likely not what you are considering.

I have also used a portable IR scope - but for distances out to only roughly 150m.
That one had a price tag of about $120.

 

[russ_watters]

Also, it matters if you are talking about thermal or near visible infrared, (illuminated or self illuminating).

 

[.Scott]

Hi I am wondering if it is possible to see the full distance of a 600m beam from a 500lm torch with an infrared filter and infrared goggles?

On taking a second look at your question, there is a problem. I was originally assuming that your 500 lumen torch was an IR torch - and that you were looking at it through a IR filter.

If it is a normal torch (aka "flashlight"), it may not put out any IR at all. So the IR filter could come pretty close to blacking the flashlight out all together.
IR will not travel through glass. So the light bulb will block a lot of the IR. If the flashlight uses a glass pane, that will block almost all of what's left.

 

[Andy Resnick]

Hi I am wondering if it is possible to see the full distance of a 600m beam from a 500lm torch with an infrared filter and infrared goggles?

This is a confusing question: if your light output is specified with 'lumens', you have no information about the radiated power outside of the visible spectrum- there could be none, or there could be a lot. Then there's the issue about 'infrared filter/goggles': what is the passband of the filter, what is the detection band of the goggles?