What Collimation tool to buy

[Blackant]

Hi all,

I've been lurking on this site for a while, reading threads and learning heaps. I've been gazing at the stars on and off since I was a kid, and I've had a lot of fun the last few years with a pair of 10 x 50 and 15 x 70 binoculars, a couple of star charts and some binocular astronomy books.

I'm getting pretty excited though, cause I've got the go ahead off my financial adviser and wife to buy an 8" GSO Dobsonian from Andrew's communications at tax time.

I need to get a collimation tool for it, and I wouldn't have a clue what to look for, or what would be best for an 8" Dobsonian.

Confession time now, it won't be my first telescope. I inherited a 114mm York Skyrover newtonian on an equatorial mount off my uncle many years ago, but to be honest, I never really got along with it. It 's been a bit of a relief to read a lot of the beginner threads on here to see that an equatorial mount isn't always the best way to go as a beginner. After reading up on how to collimate though, I'm beginning to think that this was half the problem with it, and while I wait for my 8" dob, I may as well pull this out and give it another go ;)

Previously I've just used a film cannister with a hole cut in it, but I'm thinking there must be a reason there are all these tools around for collimation :)

So, what would be recomended as a collimation tool which would suit a 8" dob, and a 4.5" newtonian reflector?

Thanks all,

Kind regards

Ant

[multiweb]

A laser collimator is handy to do a quick alignment but a cheshire is needed to do a precise alignment. I bought a kit from http://www.catseyecollimation.com/ a while back. Money well spent.

[Paddy]

I find that a laser collimator is sufficient as long as it is itself collimated, which is not difficult.

[torana68]

dont know there are any duds (but cheaper is rarely better) but I do like my laser one, and I can see that its better barlowed, so maybe if you think you will be around long enough to get the advantages v cost look for a barlowed laser , someone on here might be able to recommend one. (search the forums for colimation and read all the info , it will help you in your decision)
Roger

[Rick Petrie]

(http://www.propermotion.com/jwreed/ATM/Collimate/Chesire.htm) Hi Anthony and :welcome: to IIS.
A good and reliable tool for the job would be a collimating cheshire eyepiece which you can obtain for about $89. I use the Orion brand and have found them to be the ideal reasonably priced and good quality tool for the job.
If you check the following link it will explain most or all that you would need to know to collimate a Dob.
It will take some time to master all the reflections that you see but persevere and you will eventually become competent at it.
Good luck and enjoy your scopes.
Cheers Rick
http://www.propermotion.com/jwreed/ATM/Collimate/Chesire.htm (http://www.propermotion.com/jwreed/ATM/Collimate/Chesire.htm)

[Paddy]

I use an astro systems barlowed laser available from SDM telescopes for $198

http://www.sdmtelescopes.com.au/shop/index.php?cPath=47&osCsid=35c023fa7c88f22a3f1258f8a0d5 c738

This works really well in a truss dob which enables an easy view of relfection of the barlow end in the secondary whilst fiddling with the primary adjustment screws. I haven't tried it in a tube reflector, but would imagine its a little trickier.

[astro_nutt]

Hi Anthony,
Congrats on getting a new scope..I'm sure you'll enjoy many years of viewing...as to collimation tools I use a cheshire crosshair to align the secondary under the focuser..(after ensuring the focuser has itself been squared against the tube and aligned)..then to align the secondary to the primary...generally the crosshairs on the chershire should align on top to the spider and the crosshairs should centre on the primay's collimation ring..after this I would use a laser to "fine tune" the collimation until the beam returns precisely to it's source...
Cheers!

[norm]

Hi Ant,

Check out this site if you haven't already:

http://www.andysshotglass.com/ and drill down until you find collimation.

My preference is the AstroSystems laser collimator - might appear pricey, but works a treat.

Once you have it sorted, collimation takes only a few mins - literally.

Clear Skies
Norm

[ausastronomer]

This is the best information given so far in this thread.

A laser collimator on its own is not capable of properly collimating a telescope from scratch. It is only suitable for adjusting the primary and secondary mirror tilts. In other words touch ups on an "almost" collimated telescope. The laser is not capable of helping with the lateral positioning of the secondary mirror, or its rotation. Note, that once these adjustments are correct they rarely have to be adjusted again. The laser is handy once these adjustments are made and known to be correct. More importantly, with a laser collimator the secondary mirror and primary mirror tilts can be adjusted so as the telescope "appears" collimated, when in fact it is way out because the lateral positioning and or the rotation of the secondary mirror is out. Someone that is very experienced in collimating newtonians can "eyeball" the secondary and get it right, thus allowing them to get away with "just owning a laser". This isn't something for anyone that is not very experienced in collimation IMO.

Cheers,
John B

[Blackant]

Wow, thanks everyone for the welcome, advice and the quick replies :)

Unfortunately money is going to probably be an factor, but having said that both the Cat's eye ones and the Orion Collimating eyepiece are both within my budget.

With the cat's eye cheshire kits, are these the one's people meant?

http://www.catseyecollimation.com/cekit1s.jpg

I did a fair bit of reading about what you can use before posting, but to be honest I was a bit bamboozled by all the information :sadeyes:

This has helped a lot, ta.

Kind regards

Ant

[multiweb]

Ok, get a small laser collimator for the field (approx $150). Reason: when you're in the dark you want something quick and painless to "finish off" your collimation and you won't see any mirror central spot in the dark. The cheshire won't be practical.

At home in daylight it's a different story. You can make a sight tube (PVC pipe + fish line) with a reticule to center the secondary and buy a cheap cheshire (approx $50) to do the primary rough alignment. Later on invest in the CatEye tool kit. ($$)

If you ever get a very big aperture dobsonian a holographic laser collimator (approx. $300) is the way to go. It projects a grid and a central dot but you need to see the reflection into the secondary from the front of the tube so it needs to be pretty wide (might not work on your 8" DOB). For a big DOB that's the quickest way to align and collimate on the field. Literally 1 minute or so.

You also have to make sure your laser collimator is itself "collimated". If you stick it in a lathe or rotate it and project the dot on a wall at let's say 2-3m the dot should "reasonably" stay centered and not circle around. They rarely come aligned out of the box. Worth checking because then you'll really screw up your scope collimation if you use it and do more bad than good. Once your laser collimator is set put it in a safe place and don't drop it or it'll go out again.

Have fun. :)

[scumbag1010]

Not the same Blackant from EK

[bmitchell82]

If you get one of the standard skywatcher cheshire collminators they have a 45deg cutout, you can shine your red light and do it in the dark of night if your worried about collmination and in anycase is actually better than using just daylight! it highlights the central spot and the cheshire spot...

My best advice to save your hair and pain, is go and get somebody to show you only suffer the pian of learning yourself when there is no other option.

With my standard Skywatcher cheshire i can obtain accurate collmination for 20min exposures for astrophotography! so im happy presently. and i made a laser collminator for ease of getting the secondary angle. but in anycase you can use a cheshire to do that once you know how.!

[GrahamL]

I've stuck with my $29 andrews chesire and find it meets my needs .

http://www.piscescs.com/astro/collimat/notools2.html

[Blackant]

Hmmm I'll have to think about this one. I'd really like to spend less than $100 just to start with, so I'm thinking either the skywatcher cheshire or the orion collimating eyepiece. I have another rather expensive hobby which I've spent a lot of $$ on this year, so I don't want to push it too far, LOL.

The vast majority of the time I'll be observing from my backyard, so hopefully I won't have to collimate in the field much to start with and won't need a laser just yet. The plan is to collimate inside, very gently carry it the 10 metres from the spare room to out the back and set up.

I might even have a go at making one of these while I wait for it to arrive:

http://www.atmsite.org/contrib/Carlin/collimation/kolli2.htm#DIY

has anyone had any luck with them before? I can imagine one small measurement off while making it equals one big collimation error when using it LOL

If I have any trouble I'll join the Astronomical Society of Tasmania again, I probably should anyway. I've been a member before over the years, and they are a lovely helpful group. Only prob is I live out in the country and I find I hardly ever get to meetings to make the membership worth while...

Thanks again for the advice,

Kind regards

Ant



Yep, thats me :)

Astronomy goes well with powerkiting I find :D As the days get short and the wind too light for kite jumping and landboarding after work, all my gear starts to come back out for astronomy :thumbsup:

[Blackant]

$29 sounds good, great article too, ta :)

[TrevorW]

For a Newtonian for visual observation you can't go past collimation by eye

It works

Cheers

[Rick Petrie]

It probably works to a degree for an experienced observer like yourself, but for a beginner wanting to see all that they should, some sort of tool other than eye would be necessary to correctly collimate their scope and learning is part of the fun. We don't want new people to the hobby losing interest due to poor images when they could have nice crisp ones.

[ausastronomer]

That is without question the "worst" advice given so far in this thread IMO.

You can do it, I can do it and their are dozens of other people that can do it. All those that can do it have been collimating newtonians for years. It isn't the way to go for someone that is inexperienced in collimation IMO. Moreso, it isn't the way to go for someone that has just asked, "what collimation tool should I buy?"

Cheers,
John B

[erick]

Ant, whatever tool you end up with, it would be best if it were a snug fit into the focusser. I had a GSO laser and still have one of the el-cheapo (like $29 or whatever - someone threw it at me in disgust!) cheshires, both with 1.25" barrels. I was shown a trick which I have used successfully on both. I wrapped one layer of contact (yes, what we put down in the kitchen drawers!) around the barrel and both became a snug fit in the GSO 2"-->1.25" reducer. Both did a good job (sufficient for me) after that.

http://www.iceinspace.com.au/forum/showthread.php?t=28643

I have graduated to a Hotech self-centring laser collimator, but still happily use my cheap, contact wrapped, Cheshire from time to time.

[Blackant]

Thanks guys, this looks like the one I'll go with:

http://www.myastroshop.com.au/products/details.asp?id=MAS-133

Seems to be a good compromise between cost and quality, from what I've read on the forum Skywatcher seems to be a good brand?

Thanks for the hints on size and the contact trick too Erick :thumbsup:

Kind regards

Ant

[Starkler]

My thoughts on collimating tools:

Lasers - As said elsewhere only good for touching up an almost collimated scope. Must be a quality (read expensive) unit, as cheapies are diabolical to adjust and get right on a V-block.
No function for aligning the secondary under the focuser. You WILL need to do this sooner or later on cleaning your secondary mirror or otherwise disassembling your scope.

Catseye teletube: All in one cheshire sight tube, but I find the cheshire function hard to use in poor light when setting up around dusk. The reflective ring isnt anywhere near as bright as other models which have a window and a 45 degree slanted ring.

Skywatcher cheshire combo tool: The one I have came with a slightly bent crosshair wire. The Orion one appears to give a much better fit in the focuser.

Andrews cheshire: Too short to be useful as anything but a cheshire for final primary mirror alignment touch ups only.

I have read elsewhere that the Astrosystems lightpipe is a great choice amongst 1.25" combo tools. Peter Read of SDM may be able to get one for you.

[TrevorW]

I've used tools and I've seen tools used and I stand by what I said and as a beginner the best way to learn about collimation is doing it by eye IMHO especially for the smaller mirror sizes we use.

This is the way I taught myself from books and articles and I would say a lot of others did too. I'm not denying using a tool helps however it should be used as an adjunct to visual collimation.

FYI please refer these sites

http://www.piscescs.com/astro/collimat/notools2.html

http://web.telia.com/~u41105032/myths/myths.htm (http://web.telia.com/%7Eu41105032/myths/myths.htm)

As too the worst piece of advice, I don't think so.

Regards

[GrahamL]

I found the crosshairs a pain geoff I thought they were to thick.
I also had had a camera threaded 1.25 "adapter that I thought might of had some build issues as the skywatcher combo tool never seemed a snug fit in it .. though it worked ok .. and its new owner dosn't seem to have a problem with it..my andrews cheshire does work as a sight tube in my scope ..just .. I bought the skywatcher tool thinking it wouldn't .

Yeah to understand whats going on I found that no tools article most helpfull trev .. .. sometimes I dont bother with my cheshire If i can see things are pretty close .. you will need some tools for collimation and some info to help understand what your trying to do and how to do it. imo. .. that article well takes care of the info part :)

cheers graham

[Blackant]

Hey all,

Changed my mind and just finished ordering the Orion Collimating tool online, should hopefully get here in the next couple of days. I read a few more reviews and people only seemed to have good things to say about it.

Thanks for all the help and advice, having all the theory that people have posted for me is gonna be really helpful. Last time i gave it a stab I only had the vaguest idea of what I was doing and why :sadeyes:

I'll have a go with the 114mm York skyrover I've got, and then when my tax return arrives it will be time for the 8" Dob :D

Kind regards

Ant

[ausastronomer]

Smart Move. The Orion Collimating tool is only $20 more expensive than the Skywatcher, but is a lot better quality with much tighter machining tolerances. The Skywatcher is in fact a poor quality clone of the Orion tool.

Cheers,
John B

[wavelandscott]

Agreed, you are making the right choice!

[bmitchell82]

Yes it does work for what i need it for, and collmination seems to be fine for 30 min dslr exposures! :) though i must agree those gastly cross hairs :S when i got it i attacked it after figuring out it didn't help with a screwdriver :) now its all happy! thankyou once again :)

[Starkler]

The crosshairs are for aligning the secondary tilt. You adjust the secondary so that the crosshairs align with the primaries centre donut and this ensures that the optical axis is square with the focuser.

Ripping them out is not recommended. The trick is to get your eye to focus on the centre spot and see past the crosshairs.

[Rick Petrie]

Hi Blackant
With the Orion collimating tool the cross hairs are blurry with your eye up close. If you position your eye away a little from the hole, it is easier for your eye to focus on the cross hairs to position the centre spot on the primary. It won't take long to find the ideal position.
Once you have adjusted the secondary mirror, the primary can then be adjusted to align the reflection of the cross hairs over the centre spot.
Wahla collimation!
Cheers Rick:)

[bmitchell82]

hehehe well i actually use the outside rim of the colmination tube it proves to be rather accurate because if you can see any part up the tube your seconadary isn't right, tilt or rotation. then you place the primary mirror spot in line and your done. doing it this way my home made laser pointer which is collminated to 15 meters is dead on. the cross hairs only made getting accurate collmination almost imposible as it obscures the primary spot (not that its all that accurate anyhow being so thick. untill i get a cats eye i wont be to worried.

[Blackant]

Thanks everyone, my orion collimating tool arrived yesterday, and it's definitely a nice, solid looking bit of kit. I had a bit of a play with it yesterday, and spent a bit of time familiarizing myself with all the different parts of my telescope for collimation. Thanks for all the info in this thread about general collimation, it was really helpful :thumbsup:

Now the problem, my primary mirror has no central dot or doughnut :scared:

This means I'll have to take the mirror out of the back, mark the centre of it and put it back in. I'm going to use some of those little doughnut type stickers you use as reinforcements on sheets that go into a ring binder.

I just wanted to check I'm unscrewing the right screws to take the mirror out :shrug:

Here is a picture of the ones that I think are right:

http://farm4.static.flickr.com/3407/3659737074_fbab84ff4d_o.jpg

If anyone has any easy links to the best way to mark the centre of the mirror as well that would be appreciated.

The only other screws around are at the bottom of the telescope, and to me they seem to be the actuall collimation screws. The ones with the phillip heads and springs are the collimation screws, and the ones with the allen key heads are locking screws to use once collimation is correct:

http://farm4.static.flickr.com/3650/3658939769_4182bc99bd_o.jpg

Thanks for any advice. I'm quite happy to take the mirror out and mark it, I just want to make sure I'm undoing the right screws and seeing if there is an easy, effective way to mark it :)

Kind regards

Ant

[Don Pensack]

Though this is version 1, and I've since released version 3 of this article,
this might help to get you to visualize what's going on:
http://www.iceinspace.com.au/63-390-0-0-1-0.html
Send my your email in a private message, and I'll send you the updated v.3
Don

[Blackant]

Thanks for that Don, the article looks great :thumbsup:

I'm gonna give it a go tonight after the kids are in bed. It's the first clear night I've had down my way for nearly a week, so any luck I'll have it sorted out in time to have a look at the moon before it sets.

Kind regards

Ant

[Blackant]

Just got back inside, and yep I've rejoined the land of telescope users :D

After reading through all of the info pointed out to me on here, I pulled the mirror out, put a dot in the centre and then used my new Orion tool to collimate the telescope. Took it outside real quick as the sky was starting to cloud over, pointed it at the moon and hoped for the best :whistle:

To be honest, I wasn't to hopeful that it was gonna work alright, it seemed all a bit to easy using the tool compared to last time I'd given it a go but wow, twiddled a bit with the mount and the focuser and all of a sudden the moon leapt into clear relief :eyepop:
I was using my highest power eyepiece, a 9mm with a 2x Barlow and the mountains and craters were just so clear I felt a bit stunned to be honest. The fact that the mirror didn't have a centre dot on it may mean that it had never been collimated properly at all, but anyway I know I've never seen the moon through it that clear before.

I can imagine the real test will be when I start trying to look at DSO's like 47 tuc, but that will have to wait till tomorrow when hopefully the sky clears up a bit :)

Regards

Ant

[bmitchell82]

congratulations :D

Collminating isn't hard its just daunting! but after a few times of doing it correctly :) youll be happier than a pig in mud :)

[Blackant]

Thanks Brendan :)

We just finished our tax return, and it looks like an 8" Dob is still on the cards :rofl:

Just have to hope it stops raining by the time it arrives...