Collimation - how often?

[MrPloppy]

I think the title says it all really. I've had my scope for a good month or so now, and I've only ever collimated when I first set it up. I collimated it over the weekend, and it was quite out. Are you supposed to collimate everytime you use the scope?

Thanks,

MrP.

[Moonshane]

it depends on a few factors. the bigger the mirror and the faster the scope the more you have to 'collimate'.

what you mean by collimate depends on what you have to do.

for me there's a difference between collimating and checking.

if you check the secondary and it's aligned then are you collimating? I think you are checking. the only thing that needs adjusting more often than not, is the primary mirror alignment. this is the most important in many ways and needs to be accurate.

thankfully this is easy and takes the least time to adjust.

in summary, it's worth doing a check on the secondary alignment every time you observe. this will hardly ever need adjusting. also check the primary alignment every time you observe. this will sometimes need a minor tweak and sometimes not.

even with my big dob I rarely spend more than a couple of minutes on checking and adjustment so it's not a major chore and ensures your scope performs as best it can.

[Islander]

Collimate as often as necessary - there's no hard and fast answer to this question. Focus on a bright star and then defocus very slightly. If the star remains a true circle then you're fine. If it becomes a distorted comet-like shape then it need a tweak.

[Mikea]

You shouldn't need to collimate every time with a 200P. Maybe something was not fully tightened last time? Just do a star test every so often to check and only collimate if you need to - you can do it on the fly if only small tweaks needed (and you're brave enough!).

[8kids]

I check mine everytime I use it but that dosn't mean I need to collimate, as said above, collimate as often as is necessary. Usually it's just a tweak of the primary and takes a few minutes to do.

Gary.

[muttley]

I know every expert is going to be very concerned for my sanity, but I have never collimated my Skywatcher 200p in the 9 months I have owned it. Everything is absolutely perfectly in focus, and when I defocus I get a perfect little circle - so I am pretty sure that all is well. If everything starts to look a little blurred, or not quite as good as it used to be, then I will break out the collimating notes. I learned long ago not to tinker with things if they are fine, and collimating looks like something which can go badly wrong for the novice.

Simon

[Spec-Chum]

I'd avoid the term "badly wrong" to be honest. That implies to me something that is unfixable, or at least very hard to fix, which may scare beginners.

Anything that you do "badly wrong" in collimation can be fixed in minutes if you've had a bit of practice. I can completely unscrew my secondary, spin it round so it's shows no primary at all and have it back in prime collimation in about 2 minutes and I'm not an expert by any means. That's about as "badly wrong" as it gets.

That'd still leave the primary, but that really is child's play.

[MrPloppy]

Thanks for the tips guys. I have a laser collimator, and as has been said, putting it in and checking is no hardship, so that's what I'll do when I set up.

Much appreciated.

MrP.

[Islander]

I know every expert is going to be very concerned for my sanity, but I have never collimated my Skywatcher 200p in the 9 months I have owned it. Everything is absolutely perfectly in focus, and when I defocus I get a perfect little circle - so I am pretty sure that all is well. If everything starts to look a little blurred, or not quite as good as it used to be, then I will break out the collimating notes. I learned long ago not to tinker with things if they are fine, and collimating looks like something which can go badly wrong for the novice.

Simon

"If it ain't broke, don't fix it"

Sounds like you're doing ok to me. Don't be scared by collimation though - it's presented as some sort of black art whereas it's just moving mirrors around. Not hard to master at all really

[Mr Spock]

I check with a star test every session just in case. Can you imagine wasting a session thinking the seeing is bad when its actually your scope?

Fortunately, once properly collimated, a SCT holds collimation for quite some time. My previous scope, a 250mm Newt, needed doing every couple of months or so.

[stuffedhaggis]

I have a 200p explore. I do it every time I take scope out.

It become 2nd nature. Only really got in the habit of it once I got my laser collimator

Sent from my GT-I9300 using Tapatalk 2

[Carbon Brush]

Is this of interest?

http://stargazerslou...ation-overdone/

[Dellis]

I check mine every time I use it and adjust as and when it's out which isn't that often unless I take it apart to transport it then I have to collimate but it takes a couple of minutes at the most, that's on a 12" Lightbridge.

Dave

[cotterless45]

I check my Newts before use. Temperature changes and tube flex amy kick collimation out a bit. Once you've got the 2ndry placed all your tweaks will be the primary adjusters.

The bugbear is the Lightbridge, which just needs a tweak every time it's moved to a different part of the sky. It helps to move the ota with 2 hands and be gentle.

I'm considering changing the struts to a folding box structure.

Nick.

[Bart]

I do mine every time I use it. Sometimes recollimate during a session. Takes a couple of minutes tops with the barlowed laser technique. No messing going from EP to secondary, found that frustrating. I'd imagine any trusstube needs ti regularly. My rigid 10" kept collimation very well, only needing once or so a month, despite being pulled in and out of the garage on a sack truck. I only worry about it though if I plan to observe the planets at high mag. Also for the 16", collimation helps reduce the coma, I find.

Barry

[DaveS]

When I was using my home-made single-beam newt, many a long year ago now, I would check before every session, but would only have to tweek the primary every so often. Only after the first (Re-)assembly would I have to do a full collimation, then I'd forget about the secondary.

But then again it was (Will be soon ) working at a forgiving and now un-fahionable f/8

[cotterless45]

The barlowed laser is the easiest way to tweak collimation in the dark. It takes just a few seconds to check and adjust.

Only really fussed with planets at high mag, makes little odds with fuzzies,

Nick.

[RikM]

I check the collimation every time and adjust if necessary. Just the same as I check that my guitar is in tune before a session. It's no great hardship and ensure you are always getting the best out of your kit.

[Bart]

Only really fussed with planets at high mag, makes little odds with fuzzies,

Nick.

Dead right, meant to say this

[brucen]

Thanks for the tips guys. I have a laser collimator, and as has been said, putting it in and checking is no hardship, so that's what I'll do when I set up.

Much appreciated.

MrP.

I thought there was something wrong when I checked mine with a laser collimator as it seemed out every time although a star test suggested it wasn't. Now I have collimated the laser and use the barlowed method I haven't had to adjust anything for several months. As I keep the scope just inside the patio doors and only move it a few yards I am hoping that, now it is set up correctly, that will be it for the foreseeable future!

[Jannis]

I bought my explorer 200PDS 2+ years ago or so, never needed collimation. Neither before first use, or even today. Maybe i've just been overcareful when handeling my scope? lol

Out of focus stars make nice round circle when scope is cooled down. Been thinking about buying a laser collimator, but then again, if it isn't broken, why try to fix it?

[RikM]

A nice round circle when out of focus (like a polo mint) does not necessarily mean in good collimation. You need to use a very high magnification with very steady seeing and defocus just a little bit then look for a series of fine concentric rings. These need to be all perfect circles. Think of an archery target with very fine circles.

[Moonshane]

like many topics, I'd never criticise people for choosing to do what they do (unless it hurts others). some will never collimate, others will every time they are out (like me) and others somewhere in between. for me it's such an easy thing to do that I don't even think about it now, it's part of my short setting up procedure while I wait for my mirror to equalise with the outside temps.