Collimation of Intes MN56

Help!! I need someone to advise me or point me in the right direction for the collimation procedure on the secondary for my MN56. I am totally in the dark, and could someone kindly help me out here! Thanks for any assistance..

Sincerely,
Stan Anderson

It will take 24 hours for me to find it, but I have good instructions. ITE telescopes wrote them, and would probably help you out.

(My biggest challenge was getting the focuser square on the tube.

Stan,

The MNT has an extra optical element, the front corrector, and this adds another degree of freedom and complication because the secondary is mechanically attached to this element. Here are a few tips based on learning to collimate a MN74 I purchased in 2005. Years have passed and it's likely some of the details of the assemblies have changed in the scopes Intes-Micro shipped in later years. YMMV

In my experience, the first step in collimating a MNT is to check that the corrector is square with the optical tube and centered over the primary mirror. Intes-Micro doesn't use a full, enclosed cell for their single element correctors. The lens just sits in a round cavity with a front opening slightly larger than the glass and is held in place with three clips. If you remove the front metal ring (painted black with the ventillation holes) it will reveal these clips. One side of the cavity is machined slightly smaller than the corrector lens and it prevents the corrector from falling into the tube while allowing the inner part to rotate for tilt adjustment (like a ball in a socket). Small spacers around the edge of the glass are used to center the corrector in this opening. This sounds crude, but it works well enough as long as nothing is disturbed or loosened between the original factory alignment and the time the owner gets the scope. I-M does not use any thread locker on the screws and in thousands of miles of shipping the screws on the hold-down clips sometimes loosen, paper spacers fall out, and the corrector can be out of alignment when a customer receives it. This is all hidden by that front bezzle ring, so you have to remove it to inspect the clips and see what's going on.

If it is misaligned, getting it back in alignment and centered is not trivial, and the reference I used was the flat metal surface on the front of the tube where the three mounting clips attach. Use a caliper and measure the height of the ground flat on the front of the corrector compared to this surface. It should measure the same within +/- 0.002" all the way around. If it isn't, slightly loosen the two clips on the low side and slightly tighten the clip on the high side to nudge the corrector. Repeat until you get a consistent reading all around. The rest of the collimation procedures are essentially the same as a standard Newt. Remove the primary and adjust the focuser so it is centered over the secondary. Then adjust the secondary so the focuser is aligned with the optical axis of he tube. Finally, install the primary and adjust it so its axis aligns with the tube and focuser.

Some articles online suggest using a laser collimation tool. In my experience these are OK for initial/rough alignment, but they can have (mis) alignment issues of their own. Fine alignment of a fast MNT requires better tools, and for the last tweaks a star test is the best arbiter. I used the autocollimation tool set from Catseye to set up my MN74 and they did the job very well. This all sounds very complex, but once you've done it a couple of times, it gets easier.

One "feature" lacking on these Mak-Newt scopes is an access door near the front of the tube. With a sealed tube and the corrector in the front, there is no easy way to tweak the rotation of the secondary short of pulling the primary and reaching up into the tube. That is OK for the short focal length instruments like your MN56 or the MN74, but I often wonder how owners of a MN86 get to the secondary. Those guys must have long arms! 8)