How much difference does an autocollimator make?

Equipment Collimation
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Andy Wray avatar
Andy Wray avatar
I've been struggling to buy an autocollimator for weeks as everyone seems to be out of stock.  I have tried again to order one from a European site that says they have two in stock and am waiting.

I just wondered how much difference people think they make?

I currently use:

* A TS Concenter eyepiece to center the secondary on the focusser tube and get its rotation as round and square-on as I can
* I use a collimated laser collimator to center the secondary on the primary
* I use a barlowed laser to align the primary 
* I use a cheshire to double-check things and maybe go round the loop again
* I do now use a star test to double-check all the above

Does the autocollimator actually make a big difference?
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DEiMiC avatar
DEiMiC avatar
Hello very short and not scientifically correct answer.
NO

I almost went crazy I had an OCAL Pro…

If you master the laser and the concenter then you have absolutely no benefit!

BR
Michael

I think it could change at a later stage of development…
But that takes time…
Lorenzo Siciliano avatar
Lorenzo Siciliano avatar
I would say no. Definitely not a big difference. I collimated my newton just like you except for the Cheshire and I don't see any issue…
Michael Kalika avatar
Michael Kalika avatar
I use Howie Glatter’s laser collimator as well as Takahashi’s collimation scope. I’ve recently tried Ocal to collimate my GSO RC 8” scope without any success. I spent hours giving a chance to Ocal but nothing beats Howie Glatter’s collimator and Takahashi’s collimation scope. Maybe I will give Ocal a try again in the future.
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andrea tasselli avatar
andrea tasselli avatar
Of course it does. It doesn't mean that cannot be done without it, and nothing beats collimation at the EP. But it does allow for a very refined collimation that otherwise cannot be achieved.
Arun H avatar
Arun H avatar
Honestly - to express my frustration here- this has been asked over and over again and answered in detail. What is to be achieved by asking the same question again? I’d suggest simply looking at the previous threads.
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Andy Wray avatar
Andy Wray avatar
Arun H:
Honestly - to express my frustration here- this has been asked over and over again and answered in detail. What is to be achieved by asking the same question again? I’d suggest simply looking at the previous threads.

Sorry!  I am just trying to learn, but will now not post anything on collimation issues again.
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DEiMiC avatar
DEiMiC avatar
Arun H:
Honestly - to express my frustration here- this has been asked over and over again and answered in detail. What is to be achieved by asking the same question again? I’d suggest simply looking at the previous threads.

your opinion is ok but its easy for you ... i think you know...
Arun H avatar
Arun H avatar
What you asked is covered in those threads that you had initiated.

 Andrea had previously recommended Vic Menards book which is an excellent reference. I had also linked a detailed pdf based on Vic Menard and Jason Khadder’s work that covers the same material. Cheshires and Barlowed lasers are useful to correct Primary Axial Error. An autocollimator will correct Focuser Axial Error which the other two devices are not sensitive to. Both need to be corrected together for a fast Newtonian, though PAE tolerances are much more critical. Andrea is correct when he says best collimation is achieved using both.
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Andy Wray avatar
Andy Wray avatar
Arun H:
What you asked is covered in those threads that you had initiated.

 Andrea had previously recommended Vic Menards book which is an excellent reference. I had also linked a detailed pdf based on Vic Menard and Jason Khadder’s work that covers the same material. Cheshires and Barlowed lasers are useful to correct Primary Axial Error. An autocollimator will correct Focuser Axial Error which the other two devices are not sensitive to. Both need to be corrected together for a fast Newtonian, though PAE tolerances are much more critical. Andrea is correct when he says best collimation is achieved using both.

Thanks for all your help thus far ... as I said, I'll shut up now and just try to source an autocollimator from wherever I can as you have both recommended.  I also tried to find a way of purchasing Vic Menard's book, but even that is proving a challenge. Let's end this thread which I wish I had never have started. I apologise again.
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andrea tasselli avatar
andrea tasselli avatar
You can order directly from the catseye website, same as I did (expensive to import in the UK but worth it, IMO):

 https://www.catseyecollimation.com/perspectives.html
Arun H avatar
Arun H avatar
You can buy the autocollimator from the same Catseye website that Andrea linked for the book.

I would highly recommend a Catseye autocollimator over others. Among other things, it has both a central pupil and an offset pupil. The offset pupil is very useful because it allows you to stack two sharp reflections which is a bit simpler than stacking four reflections, two of which tend to be diffuse, using the central pupil.
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