Best collimation tool/system

[adamsp123]

Hi Folks,

I use a cheshire collimator at the moment, is there another type/specific model that can actually beat it for accuracy and is easier to use for a F/4 Newtonian scope.

I get the impression that the Cheshire is the most accurate but can be fiddly to use or am I wrong?

As always your opinions most gratefully received.

Ta Pete

[arad85]

Cheshire is "best" as it relies on you seeing with your own eyes the alignment of the mirrors. Laser (particularly barlowed) is easiest as you can see what the laser is doing as you twiddle with the collimation knobs on the primary. The problem with the standard laser method is that it is very sensitive to where the laser ends up in the focus tube - hence the SC Hotech laser collimator at £100...

[Ben Ritchie]

My vote is for the Catseye autocollimator, although I have a cheshire I use too.

http://www.cloudynights.com/item.php?item_id=2019

[dark knight]

I've ordered a SCA Hotech laser collimator at £120 for my SW and the wifes Lightbridge as it compensates for any slop in the eye piece holder as it always projects the laser dead centre every time. It may not be the only way to get accurate and consistent collimation,,but it is probably the easiest Imho

[John]

.....always projects the laser dead centre every time.....

Yes ..... as long as the laser remains perfectly aligned within the collimator body - the problem is that they don't always - perhaps the Hotech people have solved this problem, which has blighted the laser collimators that I've tried so far.

John

[Astro_Baby]

Depends what you want really....

All round simplicity and cheap plus accurate to within the degree that most amatuers would find useful - get a Cheshire

Simple for doing the primary with but can cause arguments amongst collimation afficiandos - get a laser - good ones are are expensive, bad ones arent worth bothering with.

Want the ultimate in accuracy - for those with OCD or a penchant for the very best optical collimation possible - get a catseye system - bear in mind it may end up costing as much as the scope.

I gave up in the end and just stick with a Cheshire - I feel comfortable with it.

By the way its never the collimator thats fiddly - its the act of collimating. I have done it witha Chesire and with a laser and its just plain maddening each and every time.:)

[dark knight]

The Hotech people do not use the type of modified hand held laser found in some collimator's. they use one that is specific and factory set into the housing, this company specialises in Industrial and commercial laser diode modules, so should be well qualified in working to fine tolerances.

[dark knight]

AB has reviewed one of the Hotech versions recently (not sure which one though) so is well qualified, I'll let you know what I think of the SCA version when it arrives..

[John]

The Hotech people do not use the type of modified hand held laser found in some collimator's. they use one that is specific and factory set into the housing, this company specialises in Industrial and commercial laser diode modules, so should be well qualified in working to fine tolerances.

That sounds promising then

John

[albedo0.39]

Cheshire - every single time. But, don't listen to what I say...take a look here

BTW - I'm pretty sure that if you get a decently collimated laser, you will get close to accurate as most people expect and of course, the Star Test might help you in the long run

Cheers

Steve

[Ben Ritchie]

Want the ultimate in accuracy - for those with OCD or a penchant for the very best optical collimation possible - get a catseye system - bear in mind it may end up costing as much as the scope.

Unless it's a very cheap 'scope that's a bit unfair! My set was £60...

edit: also the question was best and for a f/4 system, and the catseye system really comes into its own for critical collimation of very fast systems.

[Astro_Baby]

Ben that was said very tongue in cheek by the way

I like the Catseye system and its beautifuly made stuff as well. I think I was qouted about £180 from memory but I was going the whole hog on it and having the full on set.

I did trial the Hotech and I have to say it was a very fine bit of kit ad if I were going to buy a laser system that would be the one - I cant say how it compares to Howie Glatters system not having seen the HG products but the Hotech was miles ahead of the Baader and the basic laser collimator I had.

The collimation on the Hotech I had was perfect straight out of the box. I used it in a focuser and rotated the laser and the spot was always in the same place each time. It seemed very reliable.

My biggest bitch with lasers is that its all too easy to end up with rotation eror creeping in to the secondary as you adjust the tilt screws. You have to recheck with a sight tube all the time so to my mind it was simpler to just use a Cheshire.

In part thats a defect in the way most secondaries operate. I watched Owen collimate his Obsession scope with a laser and the very fine engineering of the Obsession meant rotation error didnt creep in while adjusting the tilt. On my scope it always does and that seems very common.

With that said a laser is a good way of doing primary alignment if you have a longish tube as you can see whats happening from the back end - its not too much of a pain with my scope but I can see if you had a slowish 8" scope that was half a meter longer then it would likley be a headache.

[Ben Ritchie]

Don't worry AB, no offense taken! I realized it was tongue in cheek

It's just that the Catseye system really is very good, and not too expensive - although I have the full set, two thirds of it is really just the standard sight-tube/cheshire and you can use any of the normal ones. The Catseye ones are well made, but nothing magical. The beauty is in the final stage with the autocollimator, which I think gets a level of accuracy beyond what I (at least) can routinely get with a cheshire - you're using multiple reflections up and down the optical tube, so you're multiplying the sensitivity compared to anything else. On its own it's not too expensive either.

My f/5 holds collimation pretty well, so generally all I do is a quick check, takes a minute or so - depending on how the weather has been and how long the OTA has been sitting unused

[dark knight]

Ben or AB any chance of a link to the Catseye system please?? I am intrigued as I have never heard of this system..

[Ben Ritchie]

The link I posted earlier covers it, the Catseye homepage is

CATSEYE Collimation Main Page Frameset File

but it's not well written and rather confusing! The autocollimator bit (which is the thing i'm really going on about) is

ALL ABOUT AUTOCOLLIMATORS

or step 3 here

Passive Tool Collimation and the Newtonian - Article

edit: i've realized that there appear to be two "step 3s" in that article, i mean the one with the heading "Eliminating all residual errors with an Autocollimator". Worth remembering that the catseyecollimation.com links are trying to sell you something, but I think the CN one is impartial.

[Helen]

I have a problem with using the Cheshire peep hole, because I wear glasses I can't get close enough to the hole. Anyone got around this problem??

Helen

[dark knight]

Thanks Ben, after reading the first few paragraphs it confirms what I thought, the wife's dob appears out of collimation. Just done a quick star test using the supplied 26mm wide angle Meade QX eyepiece that came with the scope and as the view moves outwards from centre there is massive deterioration in the fov, starts out with flaring and then just gets steadily worse,,doh there goes any viewing tonight then....

[Astronut]

If you're thinking of getting a Catseye system, it's much easier to align the triangle multiple reflections if your focuser base is adjustable (such as a Moonlite). As the instructions say, there are less errors introduced back into the system than by doing the final adjustments with the secondary screws. I'm sure many people will agree that secondary adjustment is THE most frustrating and time consuming step in collimation.

I see the latest autocollimator (Infinity XLK) on the Catseye page now has 2 viewing pupils! (the default central one and an offset one for even greater accuracy). Whichever tools you decide to get eg. sight tube, cheshire and autocollimator, I recommend the white triangle (for centre spotting the mirror) rather than the default red one as the multiple refections are much easier to see.

[adamsp123]

Thank you all for the info/ideas etc, much appreciated, I get the feeling that a Cheshire does the job accurately, all be it in a low tech fashion.

The catseye looks interesting, maybe that could be my Xmas pressy from brother who lives in the USA.

Cheers Pete

[psjshep]

Bit late to this party...

Been using a cats eye for about 2 yrs now... you can get a couple of spoting triangles for all the scopes you (will) have...

Been very useful for the faster scopes... the f/4.8 is the one which gets the most attention.

If you are at all unsure of what to get, Jim Fly is very helpful... just email him.

Phil.

[Astro_Baby]

Sorry Helen cant help on that question about using a Cheshire with glasses. No idea what a solution to that would be.

I was going the Catseye route but I keep putting it off - theres so much stuff I want to buy is the problem

Definitely agree with Ian - seconday collimation is never less than slow and quite often very frustrating.

[Helen]

Thanks AB - might just have to get a laser...

Helen