What tool for collimation

[Tim Armes]

Hi,

I'm waiting for clear skies in order to use my new scope for the first time.

I've just read this post and I've realised how important good collimation is. I had previously collimated the scope by eye, but clearly this isn't going to cut the mustard.

What's the best tool for collimation - an eye piece such as the one linked to in the above post, or a laser?

I have a Meade LightBridge so I assume that I can't go far wrong with the Meade Laser Collimator - or am I misled?

Tim

[Moonshane]

hi Tim

Personally I am not a fan of lasers but many are.

Others can comment on those but I use the following:

• home made 'collicap' (basically you can use a film canister with a 2mm hole drilled in it for this) to rough check the alignment of the secondary - i.e. can you see all three clips
  
• standard Cheshire / sight tube (with cross hairs) but with the angled face covered to check the fine alignment of the secondary
  
• cheapo plastic Cheshire (no cross hairs) to align the primary.
  

once you have properly aligned the secondary then this hardly moves and it's just a cash of checking it each time and then doing the last stage of checking the primary and making an adjustment.

after a while you'll find it easy and it takes me either no time (other than a quick check) or just a minute max to do the collimation.

good luck and worry not!

Shane

[Tim Armes]

Hi,

Thanks. For my culture, why aren't you a fan of lasers?

I ask because these instructions make it sound simple:

http://www.meade.com/manuals/TelescopeManuals/collimator.pdf

Tim

[cyborg421]

Have a look at this thread. I stand by my comment on there.

http://stargazerslounge.com/beginners-help-advice/135289-hotech-sca-laser-collimator.html

Simon

[Moonshane]

in principle they are very simple to use but there's always the worry that they may be out of collimation themselves (some are adjustable and some not) and the slop (if there is any) in the focuser might mean the alignment is not reliable.

I take the view that if I collimate using my eye then this is how I will observe too and more a match.

technically, only a star test will confirm collimation is totally accurate but in the UK the conditions are rarely good enough to do this properly.

to get it close enough to perfect for excellent visual viewing I find that the tools I use work for me and that's the point I suppose. if you do it your way and it produces good sharp, contrasty images then it's no problemo!

many people use lasers (and barlowed lasers - google 'barlowed laser collimation') successfully and happily but I prefer it 'my way'.

[twotter]

Much as I like gadgets, I also like rugged simplicity. I was very taken with the chunky alloy Astro-Engineering Colli-Mate Deluxe, which is a groovy cheshire

Astro Engineering AC656 Colli-Mate Deluxe eyepiece for collimating Newtonian and other telescopes

[Moonshane]

I tried one of these and they do look good but it was truly awful with very shiny insides and I sent it back. maybe I just got a bad one.

my used £15 standard one is a million times better.

[RikM]

I use a normal Cheshire for exactly the same reasons as Shane.

It seems 'easier' to use a laser and just twiddle the knobs until the dot's in the right place, but have never found them as 'accurate' as a good old fashioned Cheshire. The barlowed laser method is pretty good though.

[Rob L]

in principle they are very simple to use but there's always the worry that they may be out of collimation themselves (some are adjustable and some not) and the slop (if there is any) in the focuser might mean the alignment is not reliable.

This is why I stopped using my Hotech with my 250px, I got a different result every time I used it.

Now I use a collicap and Cheshire for results I trust.

[Damo636]

Even though i own both a laser (Baader Mklll) and a cheshire its the cheshire and a collicap i trust the most. To be honest i find it just as accurate. I suppose the laser might be useful in bad light but other than that i don't see any other advantage.

[spaceboy]

Another vote for the cheshire! I find a laser collimator too fussy to be reliable. Besides you need a collimation cap which the cheshire has anyway to align the secondary.

[Moonshane]

I use the Cheshire at night by shining my red torch onto the angled face. works a treat

[star_chaser]

another vote for the cheshire tho ive never tried a laser

star

[DOBBY]

It's gotta be the cheshire... & yes I have tried the laser, it's in a box somewhere

[Tim Armes]

Well, since the overwhelming majority of responses go the the cheshire, I'll take that as wise advice.

Any particular model recommended?

Tim

[Moonshane]

you can get them from FLO for £25 I think but they also come up used every now and again for £15 or so. they are all pretty much the same.

[EasyFlier]

Hello all!

As a newbie, I just collimated my newtonian the other day for the first time with a laser (the model with a target at the end).

I had never done it before, read a few articles, and got it done within 15 min. It was extremely misaligned and now I've good beautiful, crisp and sharp images.

Coming from the noob, the laser was easy and straightforward.

Cheers!

[RikM]

Hello all!

As a newbie, I just collimated my newtonian the other day for the first time with a laser (the model with a target at the end).

I had never done it before, read a few articles, and got it done within 15 min. It was extremely misaligned and now I've good beautiful, crisp and sharp images.

Coming from the noob, the laser was easy and straightforward.

Cheers!

Did you check your laser was collimated properly before you started? It is good that you have seen an improvement in your observation, but you might be able to get it even sharper. It is easy and straight forward to put the laser dot in the middle of the target, and for many people just getting the primary pointing in the right direction may be sufficient, but that is not the same as a proper collimation of the whole optical train.

If you can afford a laser and you are happy to trust it (or you collimate it properly before you start with a V-block or something) that is great.

[EasyFlier]

Thanks for your reply.

I checked before starting if the laser was properly collimated by using a jig (it was).

I not only aligned the primary, (which was grossly misaligned, outside of the target actually), and then the secondary which was quite off as well.

The most stressful part was putting a dot dead center on the primary mirror without goofing!

All went well, and I am flabbergasted at the result in comparison to what I would see before! The 114/900 has many years ahead of it!

[spaceboy]

I agree with Rik. You need to be sure the laser itself is collimated, the laser is square in the focuser IE: if you rotate the laser it still shows a collimated scope and that the secondary is correctly positioned. The only way you can be sure the scope is correctly collimated is to do a star test. I regularly do star tests when setting up my scopes to make sure all is well after carting it into the garden or dark site.

I only recently figured this one out myself Try to make sure the scope is pointing at Polaris when star testing if possible as depending on the orientation of the scope (IE: the opposite side of the meridian) flexing of the OTA, incorrect balancing, pinched mirrors or warm tubes can show errors on star tests DOH!!!

SPACEBOY

EDIT:Slow typer alert

[Damo636]

Thanks for your reply.

I checked before starting if the laser was properly collimated by using a jig (it was).

I not only aligned the primary, (which was grossly misaligned, outside of the target actually), and then the secondary which was quite off as well.

The most stressful part was putting a dot dead center on the primary mirror without goofing!

All went well, and I am flabbergasted at the result in comparison to what I would see before! The 114/900 has many years ahead of it!

Just a word of caution. The secondary mirror first has to be centered in the focuser tube and presenting itself as a circle. This cannot be done with the laser. To do this you still need some sort of collimation cap or Cheshire eyepiece. The laser is then used to align the secondary mirror with the centre doughnut on the primary.

[Tim Armes]

My scope has a doughnut on the mirror where they collimated at the factory.

If I buy a chesire, will I have to place a dot in the middle of this, or will the doughnut suffice?

Regards,

Tim

[Moonshane]

hi Tim

yes, the donut is best, for the primary, you collimate the reflection of the hole in the cheshire to the centre of the donut.

[RikM]

Take a read through Astrobaby's nice guide to collimation with a Cheshire.

[davehunt]

Hmm....I have both Cheshire and Baader Mk 3;for the record,you can check the secondary with the Baader Mk 3,and you can see the laser dot on the screen while doing the primary without dashing to and fro from the eyepiece. With my Skyliner 200p with a good solid focusser,there is no flop and wobble,and the laser produces the goods;I used to be a non-believer,but am now convinced by the laser.