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The first collimating tool, Cheshire or a Laser?

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#1 krokodilce

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Posted 20 October 2020 - 10:04 AM

I've read a lot of topics over CN about which one is better and came up to the conclusion that it is the best to have and use both.

 

At this moment I cannot afford both of them, so I would have to choose one.

 

Which one would you suggest to me between these two, and why? I currently own a 150/1200 Dobsonian, and I do plan on upgrading to a higher aperture (10" or 12"), after some time.

 

Thanks & Clear skies



#2 LIVE LONG

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Posted 20 October 2020 - 10:12 AM

  Start with a cheshire/ sight tube combination tool. I use the celestron Model #: 94182.

 

   You will always need this combination tool, even if you upgrade to a laser.

 

   Good Luck & Clear Skies!


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#3 ShaulaB

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Posted 20 October 2020 - 10:22 AM

At 150mm aperture and focal length of 1200mm, your optical tube is f8. So relax and use the Cheshire eyepiece. At f5 and below for an optical tube, stress more about it.

Back in the day, an acceptable collimation device was a plastic camera film container with a little hole poked in the middle of the base. Have no fear of collimation!
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#4 gene 4181

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Posted 20 October 2020 - 10:23 AM

 I  would want a sight tube w/ crosshairs   and a simple  inexpensive Aline collimation cap from Agena  or  the  Farpoint chesire .   Or if you can find them , a set of Tectron tools used.   IF you're going too stay with reflectors , GET the book by  a guy named Vic Menard  , New Perspectives in Newtonian Collimation.   Catseye collimation's website sells it  ,  


Edited by gene 4181, 20 October 2020 - 10:27 AM.


#5 MalVeauX

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Posted 20 October 2020 - 10:55 AM

Another vote for Cheshire.

 

Lots of inexpensive lasers are not even collimated themselves and are essentially useless for precision and are just neat toys that require collimation through a barlow or something.

 

Very best,


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#6 Sam M

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Posted 20 October 2020 - 10:56 AM

A cheshire (or some visual tool) will give you a lot better understanding if and how something is misaligned.  For example, if I remove my mirror to clean it.  When replacing:  First I eye it up, then I use a cheshire and make sure everything is centered.  Then I top it off with a laser and barlowed laser.  The cheshire would be enough on its own, but I use the laser to tweek it outside before observing.  At that point, it's usually already fine.  So, as others have said above, if you're only going to get one, go for a cheshire or other visual tool.


Edited by Sam M, 20 October 2020 - 10:58 AM.


#7 rowdy388

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Posted 20 October 2020 - 10:58 AM

  Start with a cheshire/ sight tube combination tool. I use the celestron Model #: 94182.

 

   You will always need this combination tool, even if you upgrade to a laser.

 

   Good Luck & Clear Skies!

Excellent post! Note that most cheap lasers, as already stated, have reliability problems. 



#8 SteveG

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Posted 20 October 2020 - 10:58 AM

I've read a lot of topics over CN about which one is better and came up to the conclusion that it is the best to have and use both.

 

At this moment I cannot afford both of them, so I would have to choose one.

 

Which one would you suggest to me between these two, and why? I currently own a 150/1200 Dobsonian, and I do plan on upgrading to a higher aperture (10" or 12"), after some time.

 

Thanks & Clear skies

It depends on the quality level of tools you are looking at. As noted, your f8 scope is very forgiving. What size focuser is on it?

 

I strongly recommend 2" tools if you have a 2" focuser.

 

I also strongly recommend against the cheap, 1.25" lasers that use the return beam (Lazermate). 

 

For your final step aligning the primary, a simple collimating cap will do an excellent job.


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#9 Paul Sweeney

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Posted 20 October 2020 - 01:14 PM

I started with a good laser, but even that needed collimation often. Now I have a cheshire with cross hairs, and it works well. Final collimation is on a star at high power. Cheap and easy.

#10 spaceoddity

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Posted 20 October 2020 - 05:29 PM

  Start with a cheshire/ sight tube combination tool. I use the celestron Model #: 94182.

 

   You will always need this combination tool, even if you upgrade to a laser.

 

   Good Luck & Clear Skies!

I hated that particular collimation tool. I couldn't see much of anything with it and it was extremely sloppy in the focuser. A twist lock 2-1.25 adapter helps with the 2nd issue. In fact I'd say it's a necessity. For cheap collimation, I'd just get the A-line cap, much easier to see for primary collimation.



#11 krokodilce

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Posted 21 October 2020 - 05:20 AM

Thanks for the suggestions, people. I will get a Cheshire as my first collimating tool. waytogo.gif


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#12 epee

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Posted 21 October 2020 - 06:56 AM

If you're going to get a Cheshire, get the FarPoint Cheshire. No crosshair, but far more precise than simply try to line everything up under the "X". The FarPoint Cheshire comes with triangle center spots, but you don't really need to use them.



#13 SteveG

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Posted 21 October 2020 - 03:50 PM

If you're going to get a Cheshire, get the FarPoint Cheshire. No crosshair, but far more precise than simply try to line everything up under the "X". The FarPoint Cheshire comes with triangle center spots, but you don't really need to use them.

The standard GSO black ring is far too small to use with the Farpoint Cheshire. I wanted to, but had to install the triangle.



#14 rhetfield

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Posted 21 October 2020 - 03:53 PM

Thanks for the suggestions, people. I will get a Cheshire as my first collimating tool. waytogo.gif

This should be your second collimation tool:

 

https://garyseronik....to-collimation/

 

This should be your third tool:

 

https://garyseronik....pe-collimation/

 

Both are free.


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#15 epee

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Posted 22 October 2020 - 07:07 AM

The standard GSO black ring is far too small to use with the Farpoint Cheshire. I wanted to, but had to install the triangle.

I've been getting good results with my XX12g without replacing the round spot. However, I also use the FarPoint Autocollimator to tidy things up, so that might be why.

 

Generally though, the human eye is quite adept at centering dots in a ring.


Edited by epee, 22 October 2020 - 07:07 AM.


#16 SteveG

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Posted 22 October 2020 - 12:05 PM

I've been getting good results with my XX12g without replacing the round spot. However, I also use the FarPoint Autocollimator to tidy things up, so that might be why.

 

Generally though, the human eye is quite adept at centering dots in a ring.

The autocoliimator is for residual errors in your secondary alignment. The Cheshire is for your primary axis. The latter, being the most critical. Take a picture through your Cheshire and post it here.



#17 epee

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Posted 22 October 2020 - 12:54 PM

The autocoliimator is for residual errors in your secondary alignment. The Cheshire is for your primary axis. The latter, being the most critical. Take a picture through your Cheshire and post it here.

I will, but it might be a few days. Life is pretty busy right now.


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#18 Vic Menard

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Posted 22 October 2020 - 03:03 PM

I've read a lot of topics over CN about which one is better and came up to the conclusion that it is the best to have and use both.

 

At this moment I cannot afford both of them, so I would have to choose one. Which one would you suggest to me between these two, and why? I currently own a 150/1200 Dobsonian, and I do plan on upgrading to a higher aperture (10" or 12"), after some time.

First, I agree that it's best to have and use both.

 

But if I had to choose one, it would be a Cheshire/sight tube combination tool (which is what I assume you mean when you asked "Cheshire or laser?") To be more specific, for a 1.25-inch focuser, I would choose an AstroSystems LightPipe. For a 2-inch focuser, you could add a Glatter Parallizer to your 1.25-inch combo tool (and maybe later, your 1.25-inch laser), or you could choose a 2-inch combination tool (and later, a 2-inch laser). 

 

As to why I would choose a combination tool, well...because it does everything--you can assess, and correct, the secondary mirror placement, the focuser axial alignment, and the primary mirror axial alignment. And a combination tool doesn't hide anything (like a simple thin beam laser or a basic collimation cap).


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#19 Mbinoc

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Posted 23 October 2020 - 12:38 PM

I like to use both, most suggest a Cheshire, but I have also found the laser to also be very helpful. One of the problems with a laser, (especially a in-expensive one like I have is they do not come collimated themselves).

 

This how you collimate a laser,

 

https://www.youtube....h?v=5ZsgNlgIrqQ

 

And another video that demonstrated some of there flaws.

 

https://www.youtube....h?v=gpR_gvNISrY

 

They can get you close pretty fast.


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#20 Vic Menard

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Posted 23 October 2020 - 03:32 PM

You can read more about a simple thin beam laser's "issues" here:  https://www.cloudyni...tor/?p=10545073

 

And, you can read which tools to use for which alignments here:  https://www.cloudyni...dobs/?p=4651500


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#21 epee

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Posted 09 November 2020 - 10:25 AM

At long last; my current collimation. Photo is taken through the FarPoint Cheshire...

gallery_20664_9054_223291.jpg



#22 Jon Isaacs

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Posted 11 November 2020 - 06:47 PM

My two cents:

 

If you're going to buy a laser, buy the very best and use the Barlowed laser to align the primary.

 

Jon


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#23 SteveG

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Posted 12 November 2020 - 02:44 PM

At long last; my current collimation. Photo is taken through the FarPoint Cheshire...

gallery_20664_9054_223291.jpg

Try to get it closer in, so that you can see the edges of the Cheshire. Here is what mine looks like.

 

Cheshire1.JPG



#24 epee

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Posted 12 November 2020 - 06:00 PM

I turned the focuser in closer to get a better shot of the dot.

At some point, I plan to replace the spot with the FarPoint triangle. When the clouds close in, I don't have time. When I have time, the sky is clear. Go figure - the reverse of a curse is still a curse. Thankfully, the spot collimates quite well with my gear.
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