idle thought bout cameras

Discussion in 'The Watering Hole' started by Rex R, Jan 13, 2020.

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  1. Jan 13, 2020 #1

    Rex R

    Rex R

    Rex R

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    as we know one problem with trying to 'film' rocket launches is following the rocket. had a thought about that, instead of tilting the camera...what about putting a mirror (or two) in front of the camera and tilting the mirror instead? there would be alot less mass involved. this idea is free and clear all credits should be directed to the forum.
    Rex
     
  2. Jan 14, 2020 #2

    jadebox

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    Interesting idea. I filmed (videoed?) some rocket launches using mirrors in order to be able to (seemingly) place the camera in difficult spots like almost directly under the rocket or almost directly above it at launch. The results weren't very good because the mirrors that I used were not very good. (You can get good cameras that are small enough now that you can just mount the camera where you want it.)

    You would need to use a good-quality, first-surface mirror or it would be obvious that you were recording a reflection. And the mirror being lighter and having a large flat area adds a problem. A camera is not going to shake much. But, with a mirror, the system that moves it would need to be pretty smooth to prevent the mirror from vibrating or shaking.
     
  3. Jan 14, 2020 #3

    Rex R

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    mirrors shouldn't be to hard to find, just look at telescope supplies. was thinking of the cameras that track by themselves.
    Rex
     
  4. Jan 14, 2020 #4

    jlabrasca

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    I cannot find the link now, but there is some flier who does this professionally, yes? He puts a camera on a dolly that moves away from the pad as the rocket rises, and another on a gimbal at some distance from the pad that tilts up to follow the flight

    Google the term "A t.v. camera is positioned 4000 ft from the base of a rocket launching pad" -- it is a nifty (and popular) related rates problem.

    For tilting a camera located away from the pad, it would be moment of inertia -- not the mass as such -- that you'd worry about. The angular acceleration needed to follow the rocket would go inversely as the distance from the pad. Put on a long lens, get far away, set up the axis of rotation to coincide with the center of mass of the camera, support it with a low friction bearing. It needn't take a lot torque to keep the rocket in the frame.

    Birders have solutions for the problem of following a fast moving object with hand-held camera (or scope); Lots of rifle-stock camera/scope mounts for sale, and not a few DIY rigs described on line.
     
  5. Jan 14, 2020 #5

    David M Schigoda

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    Rex,

    If you watch the first minute or so of this 7 minute video - it explains how engineers capture the flight of super sonic cannon shells, using computer controlled mirrors and high speed cameras.



    Illuminating! Your thinking was right on track.
     

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