Using a Cheshire Collimator?

[Grunthos]

my guide has you put some card down the tube to mask the reflections in the first stage of collimation.

+1

Get yourself a couple of different coloured sheets of A4.

It makes one heck of a difference in visualising what is going on!

You'll end up with your equivalent of this

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Astro Babys guide is pretty straightforward and logical to work through (and, as I found first time round, quite fun as well).

Cup of tea, Bobs Knobs, drilled 35mm film canister, Cheshire collimator, two A4 bits of paper, patience - sorted. :-)

Edited January 31, 2012 by Grunthos

[Thirdway]

That's colourful. I stuck a piece of white paper in front of the secondary and get an accurate, concentric pattern like the one shown. I'm trying to take in the next bit because none of the mirror clips don't seem to be in view?

[kniclander]

Colimation IS confusing. If you follow my guide to the letter all will be well. Thats why I wrote it to help people.

The confusing refekections are precisiely why my guide has you put some card donw the tube to mask the refelections in the firts stage of collimation.

Its very hard to explain collimation but easy to do. I tried to make it a step by step guide with each process broken down to its component parts.

Most collimation guides show the classic concentric circle pattern which you wont get with a modern newt. The simplified classic concentric view is the thing that most confuses beginners and thats

Recisely why I wrote the guide to take all factors in.

You need to read the guide and take it one step at a time. Your own cllimations is completely out of whack by the way. i would propose go back to firts principles and read either my guide or smeone elses and woek on it.

Dont be tempted to assume a laser will fix all ills, they are one of the biggest causes of beginners asking questions as to why it doesnt work and also a big reason for people having duff collimation. Without a high grade focuser ai would say they are a waste of time.

welcome back:) you have been missed:icon_salut:

[Grunthos]

I'm trying to take in the next bit because none of the mirror clips don't seem to be in view?

Not entirely sure.

AB states "You may need to move your focuser in or out to achieve a good view".

Try moving your focuser way in?

[Duns]

Hi Thirdway - I attempted collimation of my newt for the first time the other week - using Astro baby's guide. I can fully endorse the use of the card and paper tips as explained in her guide - everything becomes so much clearer and definitely less confusing.

Good luck

[Thirdway]

It's done. Took 20minutes. I think ABs guide is very good, it's probably a bit too detailed. What I learned.

1. You definitely need a collimation cap. I just drilled a hole in the focuses dust cover.

2. Use two pieces of nice bright, dofferent coloured card for blanking the optics.

3. The initial setting up of the secondary with the cards in place is just, near as damn it, your still going to need to adjust for the next stage of lining the secondary and primary mirrors.

4. The hex screws in the secondary are all about, tighten, loosen, tighten, loosen over and over until you get the mirror clips framed.

5. The primary is easy to set up. Just turn one screw and see what happens, when you get close as you can, then start on the next screw with just gentle turns and see what happens. Mine was centred with one full turn of one screw and half a turn of the other.

6. I don't have a plate protecting the mirror! There isn't an Allen key in the tools that come with the scope to loosen the primary mirror locking screws. I ended up using a screwdriver which fitted the hex.

All of this is in AB s guide I just thought these were the points which made the difference.

[LeeB]

As a final point, while i use the cheshire most of the time, after transporting I used the barlowed laser method (assuming you have a mirror centre) for a final check , it bypasses any slop/repeatability of the a normal laser and is easier in the dark.

[badgers]

I think a cheshire is the most useful thing to get first as it does both primary and secondary.

I bought a laser collimator and found that taking it out and retrying it again gave me different collimation results each time, so I got disillusioned with it.

Now I do barlowed laser collimation which is much better but I still double check it with the cheshire after.

[mr saddo]

You have to colimate the colimater laser has mine was a miles out! Easy mark a cross hair on piece of A4 stick on the wall, put the laser on a 90 degree block and rotate the laser on the cross hair on the paper, if the dot is moving in a circle off the cross hair the lazer needs adjusting, there are two Alan key grub screw covered with back sealer dig off he sealer to get to the grub screws adjust them so the lazer red dot stays still on the A4 cross hair when rotating by hand on the block.

[mr saddo]

http://m.youtube.com/watch?v=bE09_X43UUQ&desktop_uri=%2Fwatch%3Fv%3DbE09_X43UUQ

Colimate a lazer.

[Russe]

With this video I finally found out that I spent 25£ on a useless laser... it's completely out of line AND can't be colimated (lol)...

I never understood, why I get things spot on with my cheshire, but my laser was always out a mile.

If you buy a laser - test it as mentioned above by rotating it in your focuser and see if the laser spot remains in one place or describes a circle. If it does - it'll need colimating itself.

I found my new laser very helpful for adjusting the primary mirror, but I double checked with the cheshire to be sure.

[wookie1965]

I bought a laser found out it was out when my viewing session was ruined mirror was that far out, at the time did not know about barlowed way. I ended up binning the thing after spending two days trying to collimating it went back to Cheshire/sight tube and will never go back to laser here is a guide i used in conjunction with Astrobabys the first time i did it helped me enormously.

 http://www.schlatter.org/Dad/Astronomy/collimate.htm

[bambuko]

Hi Damnut,

...I'm really wondering if the non laser collimator tool is even worth having if an old film cap does the same job? Seems like I bought a tool which has no real use? Probably should have splashed out for a decent laser.

and how would you use old film cap in the darkness?

with cheshire you can shine red torch on it to do quick collimation at night

as for the laser tools... each to his/her own (I have no plans to get one )

[phoobar]

collimating just using a collimation cap 

[Charic]

For some folk, collimation is not the best way to spend their time, and the  fear builds, with the feeling of guilt/failure if it doesn't appear to work.

Take your time, and keep reading the subject. Only when you have done the task a few times, does it become apparent?  Understanding the theory, which way the mirrors move during collimation, and what your actually looking at through the tool  can all be daunting at first.

You will at some stage, become proficient in the task. 

I have used the 35mm film cannister method ( not just the cap, you actually need to drill a 1mm hole in the cap, but REMOVE, cut-off the base of the cannister!) then fit the tube/cap into the focuser. This method works very well, but could I improve?

I bought a Next Gen Laser, that needed collimating, it works, but due to the sloppiness of its fit, I'm certain it's not 100% accurate? (  equal  blame here between the body of the laser and the inside diameter of my focuser assembly possibly ?)

I now prefer the Cheshire sight tube. Still could have the same sloppiness of fitting, but this one feels tighter in the focuser than the laser. I still use what is known as the Barlowed-Laser method, to check my primary mirror when away at a viewing site. This method does not require such a tight fit in the focuser tube, so the positional/fitting error is non existent now. You need to find which method you like and stick with it.

Edited December 31, 2014 by Charic

[Astro_Baby]

If its any consolation at all I almost tore my hair out when doing collimation for the first time - years back all most of us had was a collimation cap and for the scopes back then with long focal lengths it was adequate.  A cheshire tool makes life simpler (note most modern Cheshires are in fact combination sight and cheshire tools).

Lasers in my opinion cause beginners more problems than they solve - its perfectly possible to get a good laser response when in fact the mirror are not aligned.  Solid lasers like the Hotech or the Blug are a lot better in this regard but also a lot more expensive (I have never used a blug but some people who know about collimation swear they are the bomb).

A handy tool to have with you as well is a short tube refractor collimator - they are useful for quick field collimation of the primary mirror and can also be useful on some large and fast reflectors as they give a wider view down the tube.  Some combi/schesire tools have too long a sight tube which makes them cranky at times to use with modern fast reflectors.

Half the problem with collimation, especially of the secondary, is the confusing reflections hence the paper stuffed down the tube.

I am currently revising my own collimation guide to include alignment of the focuser to ensure its square.  I originally quite intentionally left this out as it seemed to make the process even harder and more daunting for the beginner but quite a few people have asked me to include it.

Writing a collimation guide is no easy task - if you make it too simple people get bad collimation, if you make it thorough people complain its complicated  I tried to capture all of the major issues and cover them step at a time in a logical manner with drawings and pctures to help the beginner get a view of what things should look like.  I would earnestly encourage anyone with time on their hands to write a guide of their own because a) you will learn stuff yourself and you may just make a guide thats useful to others - there can't be enough resources for this kind of thing.

The funny thing with collimation is that once you have got your head round it you kind of wonder why it ever seemed so hard before.  It is a very confusing thing as I am sure most of you would agree.

If you want a really comprehensive guide that covers everything (but at the risk of your head exploding ) I can recommend Vic Menards 'New Perspectives on Newtonian Collimation'  Jason Khadder who did the illustrations for that learned tome was kind enough to review my guide and peer review to make sure its all accurate as well as to graciously allow me to use some of his drawings/schematics.  That reminds me I must get another copy - mine got lost in a recent move.

Mel

[StarcrazyGeoff]

Astro Baby.

Wendy and I are now dreading getting our new scope, after reading all this about collimation. 

We will definitely have to read your guide and no doubt buy a Cheshire. Oh aren't we going to have some fun and games. 

[ghostdance]

Astro Baby.

Wendy and I are now dreading getting our new scope, after reading all this about collimation. 

We will definitely have to read your guide and no doubt buy a Cheshire. Oh aren't we going to have some fun and games. 

Don't be worried Geoff. My 4.5" arrived from Belgium (direct from Orion Europe via Amazon) in perfect collimation, and then when I changed to the 6" Starblast that arrived only slightly out, needing a small adjustment to the primary (using the three adjusters) to collimate. The centre dot on the primary makes this easy with the supplied collimation cap you'll get with the scope. With both Orions, the secondary was fine out of the box.

Assuming yours arrives in the same condition, you'll be good to go within minutes!

[StarcrazyGeoff]

Don't be worried Geoff. My 4.5" arrived from Belgium (direct from Orion Europe via Amazon) in perfect collimation, and then when I changed to the 6" Starblast that arrived only slightly out, needing a small adjustment to the primary (using the three adjusters) to collimate. The centre dot on the primary makes this easy with the supplied collimation cap you'll get with the scope. With both Orions, the secondary was fine out of the box.

Assuming yours arrives in the same condition, you'll be good to go within minutes!

Thank you for that ghostdance. The latest information on my Orion delivery is that it will ship from Holland this Friday and I will be emailed tracking info as soon as it's on its way.

I just hope that it arrives like yours did, although I should be able to manage to get it lined up correctly, if it is slightly out. Meanwhile, we have been using the Sungar bins over the past few nights, viewing the Moon and Jupiter. Wendy was amazed how bright Jupiter was and how clear it was on the lowest magnification of 30x  Anything above that, was hard to focus on really.

Our serious stargazing will start, once we get the Orion, weather permitting    Watch out for our first report 

[ghostdance]

Holland...of course.... Thought it was Belgium, tsk

Looking forward to your experiences and thoughts with the 4.5. Mine was a faithful companion and a great introduction to the stars. I've just now improvised a stand for the 6i using a sturdy tripod and wood platform, so don't be put off by the table-top nature of these small Starblasts - stand options are easily fashioned, while keeping the utter portability benefits.

Hope you enjoy yours as much as I did and do.

[Jason D]

Lasers in my opinion cause beginners more problems than they solve - its perfectly possible to get a good laser response when in fact the mirror are not aligned.  Solid lasers like the Hotech or the Blug are a lot better in this regard but also a lot more expensive (I have never used a blug but some people who know about collimation swear they are the bomb).

Hello Mel,

Unfortunately laser collimators get a bad rap due to a basic misunderstanding about their intended use. I ran into countless frustrated beginners who would use laser collimators correctly but get frustrated because they end up with only partial view of their primary mirrors -- not being not able to see all primary mirror clips. No matter what they do, they just can't get the whole primary reflection into their secondary mirrors. Then out of frustration they would seek assistance in astro forums. Most of the time, they get the wrong typical responses about checking the accuracy of their laser collimators using V-blocks and about wrapping them to reduce slop. Many beginners give up and use their laser collimators as paper weights. 

Many miss the fact that there are two independent alignments for secondary mirrors. The first alignment has to do with rounding/centering the secondary mirror under the focuser for optimal FOV illumination. The second alignment has to do with eliminating the focal plane tilt between the eyepiece and the primary mirror by redirecting the laser beam to the primary center. A typical laser collimator handles the second alignment -- not the first one unless it comes with a holographic attachment. The first alignment is what ensures the whole primary mirror reflection is visible through the secondary mirror The laser beam does not interact with the secondary mirror edge and it can't tell you if the secondary mirror is placed optimally under the focuser -- again, unless a holographic attachment is used which spreads the laser beam to interact with the secondary mirror edge. 

In summary, it would be helpful if collimation guides explain the above. A sight-tube or a holographic attachment is needed in addition to a typical laser collimator to complete the task of collimation.

Jason

[Uranium235]

I can definitely echo the above statement in that lasers by themselves (unless its a glatter with attachments) are pretty useless. But when used in combination with a cheshire/sight tube, they do start to prove their worth. Cheshire first, laser second (then repeat if need be).

But it is still possible to get a (very) duff laser. I was given a Seben laser with one of my telescopes and bloomin' awful it was. It couldnt hit the side of a bus, never mind my primary spot!

[phoobar]

If its any consolation at all I almost tore my hair out when doing collimation for the first time - years back all most of us had was a collimation cap and for the scopes back then with long focal lengths it was adequate.  A cheshire tool makes life simpler (note most modern Cheshires are in fact combination sight and cheshire tools).

Lasers in my opinion cause beginners more problems than they solve - its perfectly possible to get a good laser response when in fact the mirror are not aligned.  Solid lasers like the Hotech or the Blug are a lot better in this regard but also a lot more expensive (I have never used a blug but some people who know about collimation swear they are the bomb).

A handy tool to have with you as well is a short tube refractor collimator - they are useful for quick field collimation of the primary mirror and can also be useful on some large and fast reflectors as they give a wider view down the tube.  Some combi/schesire tools have too long a sight tube which makes them cranky at times to use with modern fast reflectors.

Half the problem with collimation, especially of the secondary, is the confusing reflections hence the paper stuffed down the tube.

I am currently revising my own collimation guide to include alignment of the focuser to ensure its square.  I originally quite intentionally left this out as it seemed to make the process even harder and more daunting for the beginner but quite a few people have asked me to include it.

Writing a collimation guide is no easy task - if you make it too simple people get bad collimation, if you make it thorough people complain its complicated  I tried to capture all of the major issues and cover them step at a time in a logical manner with drawings and pctures to help the beginner get a view of what things should look like.  I would earnestly encourage anyone with time on their hands to write a guide of their own because a) you will learn stuff yourself and you may just make a guide thats useful to others - there can't be enough resources for this kind of thing.

The funny thing with collimation is that once you have got your head round it you kind of wonder why it ever seemed so hard before.  It is a very confusing thing as I am sure most of you would agree.

If you want a really comprehensive guide that covers everything (but at the risk of your head exploding ) I can recommend Vic Menards 'New Perspectives on Newtonian Collimation'  Jason Khadder who did the illustrations for that learned tome was kind enough to review my guide and peer review to make sure its all accurate as well as to graciously allow me to use some of his drawings/schematics.  That reminds me I must get another copy - mine got lost in a recent move.

Mel

Hi Astro Baby

For what its worth I found the hardest thing to judge right is getting the secondary mirror square to the focuser by rotating it.

[Charic]

I find the actual task of collimation straightforward. Understanding the theory and deciphering what you see through the focuser during collimation is what scares most folk away. I'm fortunate enough from training to become proficient with the eqipment i had to use. Repetitive stripping and re-assembly of the components instills confidence in the product. This just comes with practice. Understanding for some folk cannot be learnt just from reading a guide book. I reckon most folk given a one-to-one session of no more than 60 mins, if they are unfamiliar with collimation, and they'll wonder what all the fuss was about. Like most things in life, once you have been shown, you wont look back. There are several videos on the Tube, perhaps this may be more helpfull for some folk

I cant read music or play a guitar, but I can re-string and tune them! and tested by a more competent person, they found no fault.

There's no quick fix for overcomming any fears, just be patient, relax and have a go.

[why all the clouds]

When using a laser rotate the ota so the focuser is at the top, insert laser, DO NOT tighten the eyepiece locking screw, gravity will center it, as said before check collimation of the laser first and adjust as needed, SIMPLES.