I have noticed that obstructing a spotlight typically results in a blurred shadow unlike the crisp batman symbol in the comics of batman. Is there a way to create a spotlight with a crisp batman symbol?
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You need to have a focusing lens built into your projector. After that, it's just like any other movie projector sort of thing, you can focus it provided you have an object to project it onto (like a flat cloud). Physically, the clarity of the image is limited by two or three things. (1) The size of your optics (the large diameter lens) gives a limitation in that it's impossible for a lens of, say, 2 meters, to focus light in a direction more accurately than the wavelength of light divided by that diameter. For the 550 nm that the human eye adapts to at night, this is about 550nm/2m = 0.000000275 radians = 0.00002 degrees. This is probably not going to be a problem. (2) There's also a limit based on the size of your light source (the bright thing from which the light emits, for example, the filament of a clear glass light bulb). This is a thermodynamic limit; you can't focus your light source so as to produce a temperature hotter than the light source. In practice, this means that if your light source has a size of 1cm, then you can't focus the beam from it to a size smaller than 1cm. By the way, this restriction is the limiting presence in the number of pixels displayed by a projection system. High intensity (small size high light output) sources are expensive and so projector bulbs are sometimes almost as expensive as the rest of the projector. (3) If the image is viewed off-axis, a non-flat projection screen (or a translucent screen such as a cloud) will make the image blurred. But this won't be such a big deal from near where the image is projected. Neither of these restrictions will significantly degrade your image. Good hunting! |
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You can use a Laser. Just track it whit moving mirrors like the beam of a TV tube. There are computers that do an outline but its totally possible to track horizontal lines that appear and disrepair at the proper moments and the smoke from fire woks can make a perfect screen. O ya and a BIG laser. |
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If you use a huge laser (or maybe several smaller ones) you would keep the light from spreading too much. Also, it only work with clouds to reflect it! and the smoother the better. I don't know if there is another solution. |
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