grins projector, recoil and test light builds

Haha i would like t9 see it from a plane. with your calculator it comes out at 119Mcd. Here is a video taken that night by another forum member.

Is there a maximum distance ‘any’ light can throw, or is it infinite? Or is the maximum throw defined buy brightness/reflector etc?
Just curious I know it’s an odd question. For example, if you had a mirror 3x the size of yours, and the light source was 3x brighter, would it go 3x further?

Mathematically it’s infinite - you can always create a larger mirror. But at some point you’ll arrive with a light that has extremely low intensity at any distance - it just produces a beam that widens very slowly but is extremely large even at the start.

Physically - dunno.

I am not exactly sure but someone did some calculations on here and it was suggested that you need to increase the reflector surface area 4x to double the throw. I have a few big quads in to works one will be 4 GT reflectors with 4 sbt-90.2s once that light is built I will be able to take measurements and compare the numbers, I am hoping to out throw the lemax by 1km. Will be interesting to see what the numbers are.
Another thing I think determines throw and beam size is focal length. Longer focal length will give you smaller beam diameter and more throw than a shorter focal length.
Another thing is light source size.it is very hard to take pics next week or so I will try again.the 2890 has a 22mm light surface and I would estimate the spot size at 1.6km to be around 150m. A 100w HID will give a spot diameter the width of the road about probably 10-15m
Light from stars travels for years II dont really know if there is a limit.

It also depends upon the media and environment, e.g. in vacuum vs in air. For laser distance measurements the barometric pressure, humidity, temperature affect the wavelength.

Interesting. I nearly mentioned stars, but didn’t for fear of looking an idiot lol! And… they don’t have reflectors. That being the case, I can only imagine there is not limit, only to the one ‘viewing it’.
Stars are just pure brightness, and we can see some with our eyes - others we need telescopes for.
In theory, someone could see your light from the furthest depths of the universe, given a big enough telescope…… gets you thinking lol!

Light can travel infinitely, that’s how we can see outer parts of the universe, it’s because light has travelled a few billion years to get here.
So there really is no limit.
The only thing is that on earth there is atmosphere and particles and other stuff that blocks light so the intensity actually begins to decrease at a rate faster than 1/r^2, but yes you can always make a light more powerful and have it go further.
Also yes, if your mirror has 3x the front area and your light source is 3x brighter then you have 9x the candela, which means it will go 3x farther (because sqrt(9) = 3) but slightly less when you take into account the atmospheric losses as I mentioned above.

[quote=grin]
900mm mirror with CMT-2890 @ 2.8amp ridge is about 1.6km

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Wow 1.6km and bright as day. :open_mouth:
I’m thinking you may need a camera set up in a telescope to see its full range !
I really like the pic from across town, burning a hole in the sky :beer:

Have you considered a lux meter for some measurements?

Thank you :+1: , I kinda knew you’d step in and I know you are very knowledgable about it - I can’t believe I was right though lol! (3x further)

Grin , I know OZ is a vast country so I don’t want to sound ignorant - but I always thought there were a lot of helicopters there (sorry, tv programs here always showing sheep rounded up by heli lol)
It would be AMAZING to see the beam from above! - know anyone with a heli - OR a drone? :stuck_out_tongue:

Thanks for the feedback. Even constructive criticism welcome.
I am waiting for a telescope so I can see the beam, I just hope it has enough range.
I have a decent light meter but I have not been able to get consistent results so I dont like to post the readings. The other thing is this is not really a light yet and the light source is hard to focus properly because the mount isnt solid.
Goose seeing the beam from a plane would be something else there is an airport about 6km from me so I have been thinking about how to do it. I have a gsm module I can control from my phone. the lights just need a bit more work.

The next challange is going to be difficult

Parachute jump whilst filming…… :stuck_out_tongue: and get lit up! wow! NOW THAT would be a video! maybe make you pootube legend! :smiling_imp:
Maybe rope in that Felix Baumgartner Austrian daredevil! (just kidding lol) or put a balloon on a tether with a go pro?

Haha I cant do night jumps yet. They have an airshow here and I would be good to light some tiger moths or p51 even yakolevs over the local town.

Doh! I forgot about the night bit, just a tiny detail lol! :person_facepalming:

There are a few ideas I have for some cool beam shots. The cliffs I posted photos previously being one idea.

I have had more than a few goes at trying to get I think it is a lantern style of light right. Anyway this is the latest attempt.


The lens and reflector somehow got more than usual.












LED is a cree cmt-1945 5000k, driver is a taskled HBflex, it doesnt have a battery yet but is setup for external power from an 18v makita battery. the back/battery pack and base are still to be designed and built.

Your work is pure pawn grin. :beer:

i like how you tapered the body section with the heat sink fins, that adds some style points to the looks.

Plus all the large diameter inside fine threads that you’ve been able to cut.

cheers to ya.

[edit]

:smiley: :beer: