(Disclaimer: my real knowledge here is limited to "angle of reflection = angle of incidence". )
I just made a conical reflector for my Spyder about 1 foot long, from a diameter of 1 inch to 4 inch exit out of aluminum foil. It made a noticeable difference cleaning up stray spill without dimming, but was horribly crude. The goal was to create the best throw as possible, so I just extended by eye what it seemed to be doing already about 1 foot (a complete guess). The rate of spread wasn't much better, though, which was I was hoping to improve. I figured a long black tube would help, but blech.
I was thinking that the shape for the best throw might be some impossible combination of a regular parabola for major focusing, and a long thin cone/parabola for refinement of the resulting beam, but that's only based on lazy imagination. I know a know a nice parabola is best for focusing to a spot, but I have no idea what is the best for focusing from a point source to a beam of more or less parallel rays. Even with a good parabola, most of the light going out the front, not focused by the reflector, is diverging badly, which I'm guessing a shaped lens is required for (also under the catagory of "how the heck?").
It made me wonder how good it could be if done properly. Has there been any discussion on this? Is a conical reflector nearly as good as a parabolic, or not (it's a lot simpler, and I have no idea how to fashion a parabolic by hand).
Is the shape of the reflectors delivered with most lights anywhere near optimal? I just saw a thread where a D reflector was put on a mini, and it worked a lot better. Should I go buy a 12" telescope and rip out the reflector for my pocket light? Raid the nearest observatory? Or is bigger != better past some point?
I just made a conical reflector for my Spyder about 1 foot long, from a diameter of 1 inch to 4 inch exit out of aluminum foil. It made a noticeable difference cleaning up stray spill without dimming, but was horribly crude. The goal was to create the best throw as possible, so I just extended by eye what it seemed to be doing already about 1 foot (a complete guess). The rate of spread wasn't much better, though, which was I was hoping to improve. I figured a long black tube would help, but blech.
I was thinking that the shape for the best throw might be some impossible combination of a regular parabola for major focusing, and a long thin cone/parabola for refinement of the resulting beam, but that's only based on lazy imagination. I know a know a nice parabola is best for focusing to a spot, but I have no idea what is the best for focusing from a point source to a beam of more or less parallel rays. Even with a good parabola, most of the light going out the front, not focused by the reflector, is diverging badly, which I'm guessing a shaped lens is required for (also under the catagory of "how the heck?").
It made me wonder how good it could be if done properly. Has there been any discussion on this? Is a conical reflector nearly as good as a parabolic, or not (it's a lot simpler, and I have no idea how to fashion a parabolic by hand).
Is the shape of the reflectors delivered with most lights anywhere near optimal? I just saw a thread where a D reflector was put on a mini, and it worked a lot better. Should I go buy a 12" telescope and rip out the reflector for my pocket light? Raid the nearest observatory? Or is bigger != better past some point?