OCD : Obsessive Collimation Disorder

[+Bino-viewer]

Hi Folks.

 

Thought i'd start a thread on the joys of Newtonian collimation.

I'm sure this has been covered at length before, having said that i've looked on the 'Guides & Tutorials' section here,

and also over on SGL, but there doesn't seem to be much about it and nothing 'Pinned'.

 

I've not actually collimated my Newtonian yet, nor indeed used it at all.

I'm still waiting for my Dob mount to appear, and as you may know, injury has prevented me from doing anything since early October.

 

I have however, purchased a few collimation tools :

 

 

So i have a good quality Howie Glatter 2" laser, and Barlowed laser plug.

I thought i'd get the collimation cap (only a fiver) to help with secondary centering.

 

One of these is on its way too : a Cheshire collimator. This has the long sight tube with crosshairs at the end of it.

 

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I appreciate that i probably don't really need the laser with my scope at F6.3, but its an investment for the future, if i get a faster scope,

and being a bloke, i do like my gadgets !

 

So, over the last few weeks, i've spent more than a few hours trawling the web and various forums, reading (and watching) collimation tutorials.

Here are a few good ones......

 

http://www.cloudynights.com/topic/154541-how-to-collimate-your-newtonian/

http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

http://www.obsessiontelescopes.com/learning_center/collimation/index.php

 

The best one i've found, is Astrobabys (above)

 

Then their are the 'Astronomy Shed' video's. (Have a look on YouTube for them)

I'm a member on Dion's forum. I think his video's are excellent.

I have watched his collimation tutorials (there a 7 of them) several times.

 

However, his latest is really indepth.

Excellent, but it left me wondering if i really need to go that far.......?

 

>https://youtu.be/8ROvNH5uwDo

 

 

I've pretty much got the grasp of this collimation lark in principle....but

 

Here's my question.

 

This, according to 'astrobaby' is the trickiest part : secondary mirror placement and adjustment.

How accurate does this need to be ? And.........do i need to centre mark (dot) my secondary ?

Do i need to go down the path of Obsessive Collimation Disorder ? 

When i am back on my feet i shall be doing some mods to my scope, including fitting a new focuser.

This will necessitate some careful secondary adjustment. 

I will be using the methods outlined in Dions other videos ie putting the red piece of card opposite the focuser tube,

and placing an obstruction in the tube to block out the primary.

 

This is where i'm at so far anyway.

I actually quite enjoy this subject, and really want to get it sussed out totally.

Do you Dob and Newt users have any other pointers or idea's ?

Thanks, Rob 

 

 

 

Edited November 11, 2015 by Bino-viewer

[Sheila]

from an ex newt owner, I sold mine... thats my bit of advice  

 

Refractors rule

[+Bino-viewer]

Lol Sheila...........

I've only just bought my Newt and it cost less than £500 !

 

I agree with you with refractors ; i love mine.

But, at the end of the day, a 5" scope is only a 5" scope.

[Doc]

Rob

 

I done a powerpoint presentation on collimation a long time ago. I had to use powerpoint at work and I used this as practise. It looks very good and informative.

 

https://www.dropbox.com/s/z101875limcuzjy/Newtonian%20Collimation.pptx?dl=0

 

It's on dropbox as I don't know how to put it on this forum.

 

Btw I've never shown this to anyone before.

Edited November 11, 2015 by Doc

[Doc]

As long as the secondary appears as circular as you can make it and you can see all three mirror clips then that basically it.

 

I've never centre marked my secondary mirror.

[+Bino-viewer]

Thanks for the tips Mick.

Orion Optics primary mirror clips are huge ; i'm sure they'll stand out.

 

The Dropbox tutorial is great too. Thanks 

[Doc]

Years ago Dion and myself done a collimation guide using a video camera to achieve precise collimation. I've lost the file so if you want to look at that contact Dion.

[Daz Type-R]

My rule is.....

For visual, don't get hung up on perfect collimation.

Mines a F6, I collimate with a Badder MKIII laser Coli and a Cheshire, that's it.

I collimate mine, view an object, then I have borrowed a Hotech, collimated, no difference (visually).

Edited November 11, 2015 by Daz Type-R