Two words ... SNIPE HUNT!!!!!

Thanks - I figured this was the case but I figured, if nothing else, you guys would have a good laugh over it.

I should have remembered that "6 orders of magnitude" from my high school infatuation with astronomy. I've heard that in the tropics, it's actually possible to start a fire with a raindrop. I'm not sure what size of raindrop, but I decided to take your technique and work backwards, starting with the Mount Palomar 200-inch reflector. 200 inch diameter equals 100 inch radius equals area of 10000 * pi square inches. Divide this by 10^6 to get .01 * pi. Divide by pi and take the square root of .01 to get radius of .1 inch or diameter of .2 inches.

So - if it's possible to start a fire in sunlight with a lens 1/5 of an inch across, then theoretically it *might* be possible to start a fire in moonlight using the largest optical telescope* in the world. But as you say, a bit big to fit in the back pocket <img src="images/graemlins/wink.gif" alt="" />

*I know the Russians built one that's even bigger, but I understand it never did work properly.

Why not drop them a line and see if they'd try. Heck, scientists are naturally curious. <img src="images/graemlins/smirk.gif" alt="" />

I'd say you nailed it. Hehehe - sure would like to hear what happens when you challenge the guy to demonstrate...

Yeah, I thought the story was all moonshine myself <img src="images/graemlins/smile.gif" alt="" />

I have no immediate plans to pick a fight with him - unless I find he's passing on his "knowledge" to the cadets, who may be young/naive enough to believe him. But I have no problem betting all the money in my bank account that I can start a fire with my "useless" mag/flint block faster than he can with a magnifying glass and a full moon. <img src="images/graemlins/grin.gif" alt="" />

I can not get the link to work. Pete

Pete,

I think there has been a magnetic storm and the internet connection to the moon is affected <img src="images/graemlins/smile.gif" alt="" />

Burak

If you Cannot do it with your source of Illumination being something like a Streetlight,-Plenty Brighter than even the Full Moon,-Then Certainly One Can't Do it with Moonlight! It may even be Impossible to Do it with Weak Sunlight,-and Certainly Undoable with the Daylight Level of a Cloudy Day,(Plenty Stronger than say a Streetlight),-Moonlight Means are Out of the Question,-a Complete NonStarter. It's relative Dimmness Is of the Magnitude and Range Given in Other Posts.The Very Fact that it is Still Nighttime,-when the Full Moon Shines,-Shud Say Something! -Were That we Could!,-I'm just Afraid that we Cannot! I Differ,-However,-with Some's View,-that a Body's Self Illumination,-as in the Case of our Sun,-or It's Pure Reflection of Light originating Elsewhere,-as is the Case with the Moon,-Has Anything to Do with It.If a Body would Hypothetically Reflect Full Strength Sunlight,(From a Much Brighter Original Light Source),-I See No Reason Why you then Couldn't!,-Start a Fire,-from such BRITE ENUF!,-Reflected Light! But with even Full Moonlite Being So So So!,-Much weaker than Typical Sunlight!,-Starting a Fire by Mag Glass and Moonlight!,-Just Can't be Done! [color:"black"] [/color] [email]stevec[/email]

There is an optics law that says that you can not concentrate light to a higher concentration than it's source. If the moon was the source then the light could not be concentrated stronger than it is on the lunar surface. I frankly do not know if it is strong enough there or not, but I highly doubt it.

Since the sun is almost equal distance from the earth and the moon and the earth has 1/3 to 2/3 of the sunlight filtered out by the atmosphere, I am willing to say that the moon's surface has a brightness of 3 times high noon here on earth. Unfortunately that brightness is radiated or rather reflected radially in a spherical pattern and we are 1/4 of a million miles from it.

Because of the way it is reflected and diffused, not lensed, the light can effectively be considered to be generated at that intensity at the moon's surface. Following that assumption, and applying the law that the lensatically concentrated intensity can never exceed that of the source, the concentrated moonlight can never exceed the intensity of earth normal high noon, which I have never seen start a fire without further concentration which is not theoretically possible in this case.

But what do I know....