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Proposed Full Collimation without special tools
Hi All,
I am finally getting around to collimating the big binos skymaster 25x100 I bought a year ago. They came to me badly collimated, and I made them worse by trying to get them conditionally collimated. After reading some books on the subject including the navy's Optical Man 3&2 (I am happy to send the books to anyone interested), I have devised a way to partially replicate the functionality of a MKV collimator.
This is a learning exercise, and if I don't get decent results, I'm happy to pay someone to fix it before summer rolls in.
Feedback and comments are encouraged!!
1. The collimated test image. In the mkv this is a double convex lense with a test pattern at the focal point. This makes the image appear as if it came from infinity.
I replicate this by using drawing a test pattern (graduated reticle) on transparent paper and place it in the eyepiece of my 10inch dob. This is backlit by a strong light. Between the light source and the test pattern( at the focal point of the telescope), is black card with a pinhole. I am trying to emulate a point source of light at the focal point, which will be projected out of the telescope as if it was coming from infinity.
Does this work? In a collimated bino, the test pattern appears at the same position in each barrel, even though everything (the eyepiece holder, spider vanes) aren't. So there is parallax and it appears as though the test pattern doesn't move, and the nearby objects move (which is consistent with the test pattern being at infinity). Also the binos were focused at infinity using a star, and the test pattern appeared clear.
2. Auxiliary scope. In the mkv this is a low power scope with a rhomboidal prism that combines light straight from the collimator with light thats passed through one side of the bino. This lets you align the first tube with the hinge.
A few options here. Option a is preferred
2a. Align the hinge with the test pattern mechanically. There is a bar on the hinge for mounting, I could with reasonable accuracy machine an adaptor that would hold a small scope (like my 50mm viewfinder with reticle) exactly parallel to the hinge bar.
Centering the test pattern on the small scope would ensure the hinge was pointed directly at the pattern, and I could align the first tube with the hinge.
2b. Use a pair of collimated binos with a camera in each eye, and superposition the images on the computer. (I don't have suitable cameras)
Any thoughts on what I am planning to do?
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