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INTES MICRO ASTROGRAPH M73

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#1 jrms

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Posted 17 August 2009 - 04:27 PM

Hello:
I have just bought this optical tube(7" FD 540mm f:3 configuration as a naskutov-newtonian) but I have received completely uncollimated.Please have anyone a procedure to do it.
Many thanks in advance.
Jose Mundo

#2 Raven911

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Posted 18 August 2009 - 12:32 PM

It should not be much different than a standard newt. I do not think the corrector plate is adjustable. ??

It is inhumanly fast, and will be very touchy. I would buy a good and accurate set of collimation tools. I do not think a laser would work for a scope that fast.

My Mak-Newt collimates just like a regular newt, but it is not an F3 monster either.

#3 dougspeterson

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Posted 19 August 2009 - 01:25 AM

I believe the diagonal will be offset away from the focuser, as in my MN74. I have at least two scopes (the other Takahashi 212) where the previous owners apparently thought there was something wrong that they could never get the secondary shadow centered in in the star test. It is offset by design for intercepting rays at the bottom of the diagonal where its closer to the primary and therefore the light cone is larger. This effect is large on very fast newts.

#4 GJJim

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Posted 19 August 2009 - 08:44 AM

It should not be much different than a standard newt. I do not think the corrector plate is adjustable. ??

It is inhumanly fast, and will be very touchy. I would buy a good and accurate set of collimation tools. I do not think a laser would work for a scope that fast.

My Mak-Newt collimates just like a regular newt, but it is not an F3 monster either.


It is different because the secondary is attached to the corrector. The corrector axis must be aligned with the primary. On the MN74 the corrector sits in a simple metal ring, held in place by only three clamps. It can be displaced laterally and tilted in any direction. This is a really poor design mechanically, especially when the clamps come loose during shipping, and the paper spacers used to center the corrector have fallen out! :shocked: IIRC, the MN73 has a two-element corrector, so hopefully I-M has also provided a more elaborate cell design for this front element.

My MN74 arrived totally uncollimated (thanks a pantload ITE) and it was quite a chore over several weeks to get it working again. I ended up using a 10" optical flat to align the corrector and Catseye autocollimation tools for the coarse alignments of the primary and diagonal.

Minor tweaks are expected for any scope design and the owner has to deal with them occasionally. People who buy brand new equipment shouldn't have to face this kind of abuse where every element is mis-aligned. If I had it to do over, I'd send the darn scope back and tell them to fix it. Perhaps the owner of this MN73 should consider that option since at f/3, the task is even more difficult.


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