Its collimation time!! tips tricks and help.

[M00NMonkey]

Hi SGL-ers!

Ok, so I think its time i sorted out the collimation. I have a (pretty cheap) laser collimator, but i am able to adjust the laser so the collimator is collimated and I have and understand all the instructions to do this.

I have also watched and read as many videos and guides i can find on the matter, so, although a little apprehensive, I am feeling fairly confident about doing it.

The thing is, i have heard that laser can't set the secondary. But at the moment, i dont understand this?! (but i want too!!)

I have seen a youtube guide where one person completely messes up both mirrors on 200p, with the other guy not watching. Then the other guy (using the same technique used in most guides) resets both the mirrors so the scope is perfectly collimated. or so THEY say.

Does this not mean that the secondary has been set correctly? I am pretty confused over this issue, so if anyone can clarify the info for me, or point me to a link or anything. It would really help settle the old grey cells down.

Sorry if this seems a stupid question, and thanks in advance

Jez

[cosmojaydee]

http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

[Moonshane]

I don't use a laser but prefer Cheshire collimation. there are several stages to collimation and some require different processes to others. some can be achieved with either tool.

a laser cannot e.g. see that the secondary is centred in the focuser and presents a round face but in general will get collimation good enough for visual use if aligned properly which you seem to have done.

my advice is follow the guide linked to above for the first stages and then use the laser for the primary. you won't be far off.

collimation seems really hard at first but it's simple once you get your head around it.

[M00NMonkey]

Hi SGL-ers!

Ok, so I think its time i sorted out the collimation. I have a (pretty cheap) laser collimator, but i am able to adjust the laser so the collimator is collimated and I have and understand all the instructions to do this.

I have also watched and read as many videos and guides i can find on the matter, so, although a little apprehensive, I am feeling fairly confident about doing it.

The thing is, i have heard that laser can't set the secondary. But at the moment, i dont understand this?! (but i want too!!)

I have seen a youtube guide where one person completely messes up both mirrors on 200p, with the other guy not watching. Then the other guy (using the same technique used in most guides) resets both the mirrors so the scope is perfectly collimated. or so THEY say.

Does this not mean that the secondary has been set correctly? I am pretty confused over this issue, so if anyone can clarify the info for me, or point me to a link or anything. It would really help settle the old grey cells down.

Sorry if this seems a stupid question, and thanks in advance

Jez

I don't use a laser but prefer Cheshire collimation. there are several stages to collimation and some require different processes to others. some can be achieved with either tool.

a laser cannot e.g. see that the secondary is centred in the focuser and presents a round face but in general will get collimation good enough for visual use if aligned properly which you seem to have done.

my advice is follow the guide linked to above for the first stages and then use the laser for the primary. you won't be far off.

collimation seems really hard at first but it's simple once you get your head around it.

Thanks, I have read through Astro_Baby's link already, and as it is so widely refereed to it must be the best guide.

The thing is i learn and understand things much better when i actually see someone do something, rather than pictures and notes. This is because i always find that i end up questioning myself whether i have understood correctly and what i am doing is right. The niggle turns to doubt and then onto fear of making a mistake.

Appreciate the replies. I am just gonna re-read the article several times and take it slow. And not attempt anything unless I am sure.

Thanks

Jez

[Moonshane]

I completely agree with you about being shown. it's far better. try and team up with someone down your way - I bet they'll be happy to help.

[M00NMonkey]

I completely agree with you about being shown. it's far better. try and team up with someone down your way - I bet they'll be happy to help.

I will be going to Herstmonceux Obv at some point, sure they'll be someone there who will show me if I cant figure this all out before.

Im pretty sure the scope needs doing as there is a polar glare (as in glare lines going north, east, south and west) when the objects are in focus. I dont know for definite this is collimation issue, but sure i read it in one of the many articles I am reading that this is collimation probs. I am sure someone will put me right if im wrong though

[rwilkey]

I find it is helpful to do it with someone else close by, while you check the view through the cheshire, get someone else to turn the screws on the mirror, it will help get perfect collimation.

[paul mc c]

I will be going to Herstmonceux Obv at some point, sure they'll be someone there who will show me if I cant figure this all out before.

Im pretty sure the scope needs doing as there is a polar glare (as in glare lines going north, east, south and west) when the objects are in focus. I dont know for definite this is collimation issue, but sure i read it in one of the many articles I am reading that this is collimation probs. I am sure someone will put me right if im wrong though

This is the effect of your secondary spider veins,you will get this in any 4 vein spider.

[M00NMonkey]

This is the effect of your secondary spider veins,you will get this in any 4 vein spider.

Ahh, i see, well this should mean that my scope probs wont need collimation then, for at least the moment. I can take my time learning the procedure without the need of urgency.

Thanks Paul

[paul mc c]

No problem mate,give it a quick star test and this will let you know how close you are.

[M00NMonkey]

No problem mate,give it a quick star test and this will let you know how close you are.

Is there a guide anywhere, preferably with pictures. for star tests?

I found one on Astro_Baby's website. But what I am seeing through the scope (although not as bad as pictured on her site) is described as astigmatism. There isn't any mention of spider veins, or none that i can find.

Cheers

Jez

[Crimson Sunset]

Hi Jez,

What you're describing sounds just like the diffraction spikes cause by the spider veins when looking at a star, the effect is strongest when looking at a bright one. This is normal and a side effect of owning a Newtonian reflector!

For the actual collimation it's best to just have a go and see what you can do. While it is frustrating at first, you'll get the hang of it just by fiddling around. It takes your brain a little while to get used to what you're trying to do but as soon as you get the hang of it, you'll suddenly think "Why did I ever worry about this?!".

Do you have a cheshire collimator?

[M00NMonkey]

Hi Jez,

What you're describing sounds just like the diffraction spikes cause by the spider veins when looking at a star, the effect is strongest when looking at a bright one. This is normal and a side effect of owning a Newtonian reflector!

For the actual collimation it's best to just have a go and see what you can do. While it is frustrating at first, you'll get the hang of it just by fiddling around. It takes your brain a little while to get used to what you're trying to do but as soon as you get the hang of it, you'll suddenly think "Why did I ever worry about this?!".

Do you have a cheshire collimator?

Hi Jez,

What you're describing sounds just like the diffraction spikes cause by the spider veins when looking at a star, the effect is strongest when looking at a bright one. This is normal and a side effect of owning a Newtonian reflector!

For the actual collimation it's best to just have a go and see what you can do. While it is frustrating at first, you'll get the hang of it just by fiddling around. It takes your brain a little while to get used to what you're trying to do but as soon as you get the hang of it, you'll suddenly think "Why did I ever worry about this?!".

Do you have a cheshire collimator?

Hi Cameron, thanks for the post.

Yeah, Paul (above) said about the spider veins. The effect really isn't bad it didn't really bother me. It was just when i was on AB's site, I noticed the picture and thought 'oh, my scope looks like that!' so the natural assumption was to think something was wrong. Hence, I started this thread.

No, I just have a laser, which is adjustable. I started to collimate the laser itself today, but Im suffering from tendonitis in both wrists and have them strapped up and even the act of turning an allen key was causing pain. (seems to be the small fiddle movements that cause it) So I didn't finish it. Its all good though, what weather the weather being so bad, just gives me more time to totally understand.

Thanks

Jez

[Crimson Sunset]

Hi Cameron, thanks for the post.

Yeah, Paul (above) said about the spider veins. The effect really isn't bad it didn't really bother me. It was just when i was on AB's site, I noticed the picture and thought 'oh, my scope looks like that!' so the natural assumption was to think something was wrong. Hence, I started this thread.

No, I just have a laser, which is adjustable. I started to collimate the laser itself today, but Im suffering from tendonitis in both wrists and have them strapped up and even the act of turning an allen key was causing pain. (seems to be the small fiddle movements that cause it) So I didn't finish it. Its all good though, what weather the weather being so bad, just gives me more time to totally understand.

Thanks

Jez

Ouch, sorry to hear about the tendonitis. As you say though, it'll give you plenty of time to read up!

Getting someone to show you in person would be ideal. Collimation looks terrifying on paper (it took me WEEKS of frustration to get my head around it using only online guides) yet a simple demo from someone in the know would get you up to speed in no time.

If you've got more queries at all, fire away! (not that I'm qualified to answer anything, I've only been doing this for a year )

[M00NMonkey]

Ouch, sorry to hear about the tendonitis. As you say though, it'll give you plenty of time to read up!

Getting someone to show you in person would be ideal. Collimation looks terrifying on paper (it took me WEEKS of frustration to get my head around it using only online guides) yet a simple demo from someone in the know would get you up to speed in no time.

If you've got more queries at all, fire away! (not that I'm qualified to answer anything, I've only been doing this for a year )

Thanks Cameron,

I will be getting membership to Herstmonceux observatory soon, so that will be the place to get an inperson demo. As you say it'll be a lot easier to see whats going on.

From a beginners point of view, the images i get through the scope look fine. The view of the moon last night was amazing! so i don't think any adjustments are needed, for the time being at least. If the skies are clear tomorrow i will do a quick star test, i know what to look for with that now, so i will get a rough idea of how well its collimated.

Im sure there will be more questions though. If not collimating, then something else no doubt

Thanks for your interest and help

Jez

[yesteryeargames]

I am yet to collamate it perfectly , i end up making it much worse every time i have followed all the beginner guides

but the best i can get is this,

the black solid circle i cant seem to centre? is that the reflection of the callmation cap ?

[Astro_Baby]

I spunt very muct you have astigmatism to any great degree in a modern production mirror and if you did unless you were under a faultless sky I doubt you would see it.

The star test images are for reference only. A log of star test patterns particularly roughness of the mirror do look like the average star test under UK consitions where the atmopshere is nt stable. An easier test is to defocus and see id what you see looks like a doughnut or a polo mint. If thats wha you can see and the polo mint is conventfic and equal you probably have good collimation.

Hope that help some.

For a laser you will alao need a sight tube or collimation cap to set up the secondary mirror. You can ake a collimation cap feom an old 35mm dilm container or an old focuser tube cap.

If you look ag my

guide theres a pic of a collimation cap and thats what you need to handle the sceondary alignment.

[M00NMonkey]

I spunt very muct you have astigmatism to any great degree in a modern production mirror and if you did unless you were under a faultless sky I doubt you would see it.

The star test images are for reference only. A log of star test patterns particularly roughness of the mirror do look like the average star test under UK consitions where the atmopshere is nt stable. An easier test is to defocus and see id what you see looks like a doughnut or a polo mint. If thats wha you can see and the polo mint is conventfic and equal you probably have good collimation.

Hope that help some.

For a laser you will alao need a sight tube or collimation cap to set up the secondary mirror. You can ake a collimation cap feom an old 35mm dilm container or an old focuser tube cap.

If you look ag my

guide theres a pic of a collimation cap and thats what you need to handle the sceondary alignment.

Thanks for reply AB!

Yes, i was going to try the defocusing image to estimate the collimation, and get a rough idea. And the pictures on your site are very helpful, its only because im new that its just taking time to get my head round it all!

Thanks for the tip about film canister cap too, I got a few of them so i will dig them out.

Again thanks for the time you have put into your site, and also sharing your thoughts and advice on SGL. It seems the humbling nature of astronomy really brings out the best nature in people. Its a shame more people don't take up the hobby/past-time/ career, as there is no doubt in my mind it would make this small planet a much better place.

Jez

[Astro_Baby]

To be honest id the are tis and tricks its these......

1 wear some cotton gloves when near optics. Ou can get cotton surgical style gloves from Boots for a few quid. A worthy investment as it will reduce the risk of any sweat getting on the seckdnary if you have to adjust it.

2 remove all jewellry before handling optics, rings, watches etc are a hazard near glass optical stuff and ai have seen a few posts in my time of people scratching or chipping optics thanks to a wristwatch.

3 firts time round collimate with the tube horizontal so that if anything is dropped it doesnt go down the tube and hit the primary mirror.

4 biggest tip of the lot, go slowly and exercise patience, STOP and THINK between each step and if things arent going well then take a break. Allow plenty of time and dont rush. If its all getting too much, your brain starts melting etc go have a cuppa, watch the box, walk the dog...just get away from it for a bit.

[yesteryeargames]

Uploaded with ImageShack.us

as good as i can get it :S

[Lee M]

I read through AB's guide when I first got my scope. I only had a collimation cap and worked through the first three parts (vaguely) not feeling at all confident in what I was doing.

I couldn't see anything obviously wrong so I just got on with it and went and used the scope.

A few weeks on and now with a Cheshire I thought I'd got through again. What a difference a few weeks make. Having a bit more confidence with the scope, not having to think twice over which is primary and secondary, etc. I rattled through the first three sections feeling far happier that they were indeed correct or at least close enough that I couldn't be sure they were out to any significant degree.

So, onto the primary mirror with the Cheshire for the first time.

NOTE FOR THE UNINITIATED - you are not trying to focus on the crosshair wires inside the Cheshire, you are looking at the reflection of the crosshairs on the mirror.

I probably spent a good few minutes thinking:

'This crosshair is far too fuzzy to line up'

'I should have bought a more expensive Cheshire, this one is rubbish'

'I can't see how this process can be precise!'

Then the penny dropped that the spder vanes on the image don't (can't) go all the way to the middle and the Cheshire crosshairs were just lined up with them. And that's what I was supposed to be looking at.

Eureka!

And it was spot on. So I haven't needed to adjust a thing yet.

Hope that's helpful to someone and saves someone a bit of head scratching.

Lee

[Lee M]

Sorry, I forgot to add, many many thanks to Astro Baby for the excellent guide it really is a fantastic help.

Cheers

Lee

[bingevader]

To be honest, I know it's miserable outside and the urge to do something astronomical is growing by the day, but if you've not had your 'scope long I'd leave the collimation for a bit and just enjoy the few clear nights we're getting.

Most Skywatchers are pretty good straight out of the box.

Unless you've reason to doubt it, I wouldn't worry too much.

Yes, it is theoretically possible to incorrectly align a 'scope with a laser collimator, but if you use Astro Baby's guide and align your 'scope in order starting with the secondary mirror, you shouldn't go far wrong.

Cheers

[M00NMonkey]

To be honest, I know it's miserable outside and the urge to do something astronomical is growing by the day, but if you've not had your 'scope long I'd leave the collimation for a bit and just enjoy the few clear nights we're getting.

Most Skywatchers are pretty good straight out of the box.

Unless you've reason to doubt it, I wouldn't worry too much.

Yes, it is theoretically possible to incorrectly align a 'scope with a laser collimator, but if you use Astro Baby's guide and align your 'scope in order starting with the secondary mirror, you shouldn't go far wrong.

Cheers

Hi Bingevader,

Agreed. Yes I have astro-fever bad!! haha. but I am in no rush to possible mess anything up

The views I had the other night were amazing and seemed really crisp, so Im sure collimation will hold off for a while, while I just enjoy the scope. I will do a basic star test (defocusing) the next clear night we have (maybe tomorrow, but rather than clouds it looks like wind could be a problem!! ) and that will give me a rough idea of the collimation.

Thanks

Jez

[M00NMonkey]

I read through AB's guide when I first got my scope. I only had a collimation cap and worked through the first three parts (vaguely) not feeling at all confident in what I was doing.

I couldn't see anything obviously wrong so I just got on with it and went and used the scope.

A few weeks on and now with a Cheshire I thought I'd got through again. What a difference a few weeks make. Having a bit more confidence with the scope, not having to think twice over which is primary and secondary, etc. I rattled through the first three sections feeling far happier that they were indeed correct or at least close enough that I couldn't be sure they were out to any significant degree.

So, onto the primary mirror with the Cheshire for the first time.

NOTE FOR THE UNINITIATED - you are not trying to focus on the crosshair wires inside the Cheshire, you are looking at the reflection of the crosshairs on the mirror.

I probably spent a good few minutes thinking:

'This crosshair is far too fuzzy to line up'

'I should have bought a more expensive Cheshire, this one is rubbish'

'I can't see how this process can be precise!'

Then the penny dropped that the spder vanes on the image don't (can't) go all the way to the middle and the Cheshire crosshairs were just lined up with them. And that's what I was supposed to be looking at.

Eureka!

And it was spot on. So I haven't needed to adjust a thing yet.

Hope that's helpful to someone and saves someone a bit of head scratching.

Lee

Thanks for the moral support Lee

I can sort of understand the guides, but similarly to you, I am questioning whether I have understood. To me, its an expensive bit of kit and the last thing I want to do is rush something that could possible damage it. Not that I think I would damage, mind you.

I need to get some cotton gloves first though. I wouldn't have thought of that unless Astro_Baby had mentioned it here and on her site.(Thanks AB!).

I am just gonna enjoy using the scope as is for now though. Saturns hot on the list, hopefully clear skies and a tad less wind 0200am thurs!! Here's to hoping

Cheers

Jez