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Thread: Far Field Alignment idea

  1. #1
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    Default Far Field Alignment idea

    Just had an idea so I wanted to pass it along. Have not tired it yet.

    There are two problems with far field alignment. Well many but two I am dealing with. One is old eyes and glasses and the other is distance. With glasses the colors are refracted like prisms so the overlap could look off even when spot on. distance drops the ability to separate closely spaced objects.

    The most common thing done is use a mirro to return the image closer to the starting point. That can and does work. Here's a few more.

    Two ideas now...

    one use a video camera fitted with an nd filter and ground glass. Now you can remotely see the image on a monitor. The security wireless cameras are dirt cheap these days.

    second. I wonder if you scan a circle and place a plastic cone in the path mounted in front of the scanner pair if you might make a sort of jig. The idea is to scan the circle so it just fits the cone and then a tiny bit more. Now look at the lip of the cone to see if you see overlap or part of the circle missing. The cone will exaggerate the misalignment if you are off. Would be best on different colors rather than for aligning two of the same kind. I'm probably not explaining this clearly. Ask questions.

    The idea is to put some reference in the adjustment plane so you can see how much you are in or out. I guess you could close the end of the cone and just use it like a screen but then that would not be far field adjustment nor is the cone really. So back to one far field and one near field idea.

    The reason i like the video idea isn't just ease of use but you can blow up the lines and see the divergence differences and maybe compensate. I've not had good luck with that. seems if you match the way out diveregence then the close in and medium distance divergence isn't the same. You don't truly change divergence with focus.

    Ideas are free. you get what you pay for. hope it works for someone.

  2. #2
    swamidog's Avatar
    swamidog is online now Jr. Woodchuckington Janitor III, Esq.
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    a good trick for farfield alignment is to bounce the beam back to where you are and into something translucent like a sheet of paper. do the alignment based on what's projecting through the back side of the paper.

    Quote Originally Posted by kecked View Post
    Just had an idea so I wanted to pass it along. Have not tired it yet.

    There are two problems with far field alignment. Well many but two I am dealing with. One is old eyes and glasses and the other is distance. With glasses the colors are refracted like prisms so the overlap could look off even when spot on. distance drops the ability to separate closely spaced objects.

    The most common thing done is use a mirro to return the image closer to the starting point. That can and does work. Here's a few more.

    Two ideas now...

    one use a video camera fitted with an nd filter and ground glass. Now you can remotely see the image on a monitor. The security wireless cameras are dirt cheap these days.

    second. I wonder if you scan a circle and place a plastic cone in the path mounted in front of the scanner pair if you might make a sort of jig. The idea is to scan the circle so it just fits the cone and then a tiny bit more. Now look at the lip of the cone to see if you see overlap or part of the circle missing. The cone will exaggerate the misalignment if you are off. Would be best on different colors rather than for aligning two of the same kind. I'm probably not explaining this clearly. Ask questions.

    The idea is to put some reference in the adjustment plane so you can see how much you are in or out. I guess you could close the end of the cone and just use it like a screen but then that would not be far field adjustment nor is the cone really. So back to one far field and one near field idea.

    The reason i like the video idea isn't just ease of use but you can blow up the lines and see the divergence differences and maybe compensate. I've not had good luck with that. seems if you match the way out diveregence then the close in and medium distance divergence isn't the same. You don't truly change divergence with focus.

    Ideas are free. you get what you pay for. hope it works for someone.
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  3. #3
    Join Date
    Nov 2008
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    Cleveland Ohio
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    Yes that is the traditional way. Was th8nking of doing this tonight but.....zero visibility equals beam show time. My yard slopes down so itís perfect

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