collimation (how often?)

[garyp]

I've been reading threads about collimation and all the fun that goes with it

My question is how often do you usually have to collimate? I am new to astronomy and have recently bought an 8" reflector. Iv'e had it 6-8 weeks and used it 2-3 times a week on average.I haven't transported it any where just taken it ouy to the back yard every time.

I haven't done any collimation yet simply because I don't think it needs it. I based the assumtion on the fact that I am happy with what I see. Everything is clear and sharp on good seeing nights. I also test it on stars by taking it out of focus as the instructions say and it seems fine.
Someone experienced might say it needs collimation but to my eye I am happy with the view.

I know my question may be like "How long is a peice of string?"
I just wondered what experiences others had and how varied they may be.

[renormalised (Carl)]

How often??. As often as you have to, and is necessary. It all depends on how well your mirror has been setup in the first place. It may need collimation every time you use it, or it may not need it for a month of two. But I would suggest that any time you have to move your scope about or it takes a bump, knock, whatever, that you check the mirror's alignment and then adjust it accordingly. It might only need the slightest of tweaks, or a good general re-alignment.

[madtuna (Steve)]

"I haven't done any collimation yet simply because I don't think it needs it. I based the assumtion on the fact that I am happy with what I see. Everything is clear and sharp on good seeing nights. I also test it on stars by taking it out of focus as the instructions say and it seems fine.
Someone experienced might say it needs collimation but to my eye I am happy with the view."

Hi Gary,
If you are happy with the sharpness and clarity leave it alone.

The more experience you get and especially if you look through a few other people scopes, you'll get to know if it needs collimating or not.

Don't attempt it without the right tools and until you really think it needs it lest you make it worse.
As for the best and easiest collimating tools and how to...you'll find that all on here and heaps of people who will walk you through it.

[iceman (Mike)]

I collimate every time I take the scope out - at the beginning of the session.

And for imaging, I usually re-collimate when the scope changes where it's pointing significantly. So i'll collimate at the beginning when it's pointing lower, then check/correct collimation when it's pointing near to straight up. Sometimes it doesn't need any adjustment, sometimes it needs a tweak. The mirror can shift slightly as the scope moves around the sky, so when you're after the best resolution to get the best images, it's worth checking and re-checking collimation as often as you can spare the time for it.

[AlexN]

I've got an 8" also... Had it for about 3 months now and have only needed to collimate it once... Its done 3 or 4 200km round trips to dark skies, and gets taken out side AT LEAST 3 times a week...

My understanding is that as the scope gets bigger it will require collimation more often....

Alex.

[Kevnool (Kev)]

I Colliamate every time i use any one of my scopes because just say i spent $1000 or $3000 or $300 on my scopes i will want every cent i spent to get the most perfect image available (money for image).

But thats only me.......cheers kev.

[erick (Eric)]

I check collimation everytime I get one of my scopes set up for use. Typically my scopes get pulled apart and transported some distances between observing sessions. In general they stay in good collimation. The 8" seldom needs any adjustment.

If you are enjoying what you are seeing, that's what it is all about.

[Jen]

Im still learning how to get this collimating thing down pat first before i wonder how often i need to do it

[vash (Ashley)]

I collimate every time I get the scope, once you learn how to do it you can get it done in a couple of minutes.

[Chippy (Nick)]

I have an 8" dob and find that it doesn't need collimating very often. If yours is F6 then you'll likely find the same. F6 is a lot more forgiving than F4 or even F5, and as mentioned the smaller (and lighter) mirror probably helps as well. If it ain't broke - don't fix it, I say.

Sooner or later you'll have to get your hands dirty though ;-)

[huckabuck]

hi guys(and gals), i've been away from the confuser for awhile. hope everyone is doing well. anyway i have been looking into buying a collination tool(s). what is the prefered instrument you folks use? i always just collimate with the star test. is there anything more accurate? most instructions i've read end with the star test......so why bother with anything else?

[Liz]

I had/have an 8" Dob which I didnt collminate at all in its ? 7 year use , now with the new(ish) 10" I have done it twice, tho have also taken the mirror off twice!! I use a little Newtonian Collimator (Andrews) - which is quick and easy to use.

[ngcles]

Hi Gary,

The answer in the end is basically each to his/her own. Some people can become so retentive about it they spend more time collimating than observing. I like to think I'm a bit more relaxed than that. Collimate as often as you feel you need to do it. Don't sit around feeling guilty about it — enjoy the 'scope.

Collimation is like riding a bicycle and the more/more often you do it the better you become at it. At the start, it can be tremendously frustrating once you start fiddling but eventually, once you learn the ropes and become familiar with the routine, it won't seem like a burden at all — just like a guitarist tuning up before they play. The first time you do it you will likely make a dog’s breakfast of it (like many, if not most of us) but don’t worry at all, there’s nothing (well, very, very little) that can’t be fixed with a few simple turns of the knobs – and there’s plenty of advice on tap here – just search the threads for a start and ask more questions. Join a club

If a newtonian is permanently mounted somewhere and it has a reasonably solid mirror cell it likely won't need collimation often — and then only an occasional tweak to fine tune.

Solid tubes that are assembled/disassembled moved around/transported and used a lot require it more.

A truss-tube dob basically needs collimation every time you assemble it because it simply won't go together precisely the same way every time -- no matter how well made it is. Even so, with my 18”, I rarely have to collimate the secondary and provided I've got an assistant to turn the knobs while I look in the cheshire, it rarely takes more than a minute.

My home-made solid tube 31cm on GEM has very robust cells (Novak) and hardware and even after the longest/bumpiest trip it rarely needed more than a tiny tweak. More often than not, it was spot on — so, well engineered 'scopes also need less attention. Mass-market solid tube dobs probably need a bit more attention for best performance.

Best of luck with it and remember — don’t feel guilty about it. Equally, don’t feel frightened of the telescope either, newtonians are not easily broken!

Best,

Les D
Contributing Editor
AS&T

[garyp]

Thanks for all your responses. your experiences give a far better understanding than any instruction manual ever could.

Now I can relax and enjoy the view.