Mon.14th TS binoviewer misalignment.

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The sky was still clear in the late afternoon as it darkened with the moon still high in the SE. So I tried combinations of the binoviewer with the GPCs and Barlow and different eyepieces in the 7". As the powers rose I discovered a serious misalignment in the TS binoviewer. The views in the left and right barrels were vertically offset.

After an hour or more of struggling with this, my [normally good] distance eyesight had changed. Bright, naked eye stars were now all double! With a constantly changing, vertical offset. This wasn't a small effect either. Because the distance between the two star images was several moons in diameter! The moon also looked double and I was unable to focus my eyes properly to make a sharp, single image.

By now I had a splitting headache from the eye strain and was feeling queasy. For a while I had gone back to using one eye with a star diagonal to give my eyes a rest. It had still taken over a quarter of an hour for all the double stars to merge back into single stars again. Fortunately I had to call a halt just then to go in for dinner.

Images taken through the empty binoviewers with the camera lens against the nosepiece. It is obvious that everything in the image is duplicated. The hedge on the left was about 30' away. 50' on the right. It has occurred to me that binoviewers would be set up for parallel light at a great distance. So I checked more distant views. The woods at 500 yards were just a fuzzy mess when seen through the binoviewers 'backwards.'

It's odd that I hadn't noticed the problem when using the binoviewers on the sun. Perhaps it was the low powers I had been using. I still have only 3 pairs of secondhand Meade 4000 eyepieces so far for the binoviewer. 32, 26 and 20mm. [For 41, 50 and 65x] I need a Barlow lens or GPC to get higher powers but find the step up in magnification too extreme even with the 32mms. The second 20mm EP has only just arrived so I have only ever used up to 50x with the 26mm.

The effect of stereo viewing on the moon was quite stunning at first but quickly grew unpleasant with higher powers. I kept trying different combinations to see if it helped but should really have given up much earlier.

Looking through the bare binoviewer's entry point at arm's length, at very distant objects, shows two badly offset images. The moon was rotating about its double as I turned the binoviewers around their own axis in my hand. I will have to dismantle the binoviewers to see if I can re-collimate them myself.

Cutting the long story short: I carefully removed one plastic body cover. They are secured by the front screws but the sides of the moulding seem to be clipped very firmly into place.

Take great care if you are tempted to try removing these covers yourself. There is a patch of glue visible once they do come apart. So the factory obviously hoped you wouldn't try. I can accept no responsibility for your own clumsiness if you do try to take these apart. Nor have I suggested that you copy my example. I have a very long lifetime of making [and breaking] things to guide me.

I soon discovered that the TS binoviewer prisms are not intended to move internally from the factory settings. Big dollops of white cement lock the prisms firmly in place. The collimation screws are also glued over to avoid user adjustment.

It seems obvious that these binoviewers have been factory misaligned and cannot be corrected by amateur means. Nor are they likely to go out of alignment with slight bumps in normal service. I have contacted the dealer to see what they have to say.

Update: I have been asked to return the binoviewer for examination by the dealer. Date of dispatch was March 19th 2018. 10 months ago. They have hardly been used since new and were always treated with the greatest respect. Being automatically returned to their padded case when not in active use.

Click on any image for an enlargement.

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