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Hi Rob,
Glad to hear you are inspired by Pauls bino- creation.
What you missed was not fundamental problem , just very crafty solution.
Co-collimation refers to the two optical trains being parallel, hence merged images.
Each mirror sits on two point edge support bolts at 90 degree angle. Winding the bolts allows you to translate each mirror in horizontal / vertical plane and the normal 9 point cell mirror sits on allow usual tilt adjustment. Each mirror flotation sits on a hinged plate with long handle attached for adjustment from the eyepiece.
On the initial night of use, an iterative process is undertaken whereby, after perfectly collimating one side, the images are co-collimated ( merged ) , and then checked for individual true optical 'collimation'. By shifting one or both primary in XY translation plane with the edge support bolts, and then re-tilting the secondaries as need, you are in effect adjusting the parallelism of the two optical axis.
Once you have acheived good co-collimation, with both sides also being in good collimation through the iterative adjustment of the primaries, this adjustment is never needed again. The routinely small tweaks needed then after every setup, or with high power eyepieces, are done with tilting the primaries by the two hinged plates. We also rely on a really good truss system that has great repeatability, for tha I heartlily recommend the Moonlite ball and socket truss connectors. The detection and removal of relative `field-rotation' between the two views which is actually a far more distressing than mis -cocollimation can be subject for another day.
Yes, technically there may be a slight loss of collimation , through this practise of using primary tilt for the final merge. In reality the shift is needed is usually so small, as not to cause any noticeable loss in resolution. The views are stunning. I had my best telescopic views of Jupiter ever very late at night at SPSP. The brain seems to co-add the fleeting detail seen not necessarily concurrently in each eye to form a solid image with all the detail intact. Its almost like flicking a switch...when there is enough data to form a solid image Jupiter seems to go from a blur to hubble like view, and not much in between.
No binoviewer seems to give this effect. Remarkeably body heat just doesn't seem to be the problem that people suggest for reasons I think again due to distortions being different in each eye at any moment. These things were built for deep sky anyway. The contrast in dark nebulae is stunning. They showed the Horsehead at Lostock without a filter, and everything including colours of the stars and apparent eyepiece field is enhanced.
Mark
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