In theory this could work, but in practice, it would not be possible to move the mirror fast enough to be effective. In theory, if you reflected the light from one mirror in the optical path to a second mirror which reflected the light back towards the viewer then moved the first mirror to allow the original light to pass through and everything were in phase and aligned properly, then in the period of time when the two light waves overlapped each other, the light intensity would be increased. The underlying principle you are describing is the same principle that makes anti-reflective and enhanced coatings work. The coatings are applied at a controlled thickness. If the coating is 1/4 wave thick (or odd multiples of 1/4 wave like 3/4, 5/4 etc) then the coating will be anti-reflective. If the coating is 1/2 wave or multiples of 1/2 wave thick it will increase the reflectivity. This occurs because the clear coating creates a second reflection. If the light waves that are reflected by the coating are in phase with the light reflected by the optical surface those waves are additive and increase the reflectivity of the surface. This is used to "enhance" coatings on a telescope mirror. If the light waves that are reflected by the coating are out of phase with the light reflected by the optical surface then this reflection cancels out the reflection on the optical surface and is used as an "Anti-reflective" coating. Depending on the desired result, the same coating can be used for either purpose BUT would be applied at a different thickness. However in use, optical shops use different materials in their coatings to achieve different optical properties and have varying levels of quality. The better ones are closely guarded trade secrets. John Zeigler -----Original Message----- From: Lambert, Aaron [mailto:Aaron.Lambert@Williams.com] Sent: Tuesday, August 23, 2005 12:42 PM To: Utah Astronomy Subject: [Utah-astronomy] Telescope Theory I will start this off with another disclaimer. It has been several years since I took physics and I have not done much with the art of telescope making except for one small project that Chuck helped me with. On my way into work this morning (I ride the bus, so I get plenty of time to think), I came up with an idea. Again, this is based on ignorance, but hear me out and then shoot me down. :) I was pondering a way to increase the light-to-eye value for telescopes, ideally allowing a small scope to show the same detail only visible in a larger scope. I had thought previously about using some kind of device that captures light (like a CCD) and then duplicates it to enhance the image, but I do not think that would work, or it would be just like staring at a screen instead of letting the photons hit your eye. But let's say you could take a small tube (perhaps the size of a Barlow) and put a one-way light valve (mirror of some kind?) at the end coming from your scope and then have a reflective shutter at the eyepiece end which opened and closed several times per second. The light would enter the tube and have a 50% chance of reflecting twice before entering the eyepiece. The result (in my mind) would be that you would have alternating periods of no light reaching your eye and then double light. This would give an effect similar to watching a movie (one frame at a time) or looking through the slats of a fence while driving - your mind can still stitch the image together so it is cohesive. The question is, would it provide the desired effect of increasing the detail of what you can see? Is there anyone out there that can shed some light (pun intended) on this? Thanks, Aaron _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com