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Thread: Physics question: interference pattern?

  1. #21
    Join Date
    Feb 2007
    Location
    Fort Mill, SC USA
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    1,507

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    Quote Originally Posted by Eidetic View Post
    When collimating without a shear plate, I use a monocular to see the target across the room. Draw the intended diameter circle on a black card and tape it to the wall, or use a white card and alignment goggles. Get it as far away as possible, so you can easily see the target in the telescope.
    For easier colimiation, are we overthinking this a tad? (Not that it isn't fun to overthink problems on occasion.) We aren't talking about automation, are we?

    When colimating and doing far-field aligning I put a bounce mirror on the far side of a room and have it reflect back to a white wall sitting directly behind the projector, module that I'm working on. (In my case, the combined throw is about 25 meters.) This allows me to colimate or align while looking at the beam on a wall that I am already facing. At about 50cm with beam power kept quite low, so there is no eye strain from either distance or brightness.

    -David
    "Help, help, I'm being repressed!"

  2. #22
    Join Date
    Jun 2010
    Location
    Blacksburg VA
    Posts
    137

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    Can't you use any old clear material for shear? The flatness difference will make your fringes wiggly but you should still be able to see when you get closer to collimated.

  3. #23
    Join Date
    Oct 2010
    Location
    Athens, Greece
    Posts
    1,930

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    Maybe one prism of an anamorphic prism pair?
    "its called character briggs..."

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