What is collimation????

[legoalan]

Hi everyone, sorry for the newbie question but what is collimation? I've read that it only really applies to reflectors (which I own one) and about how well it focuses? Can anyone please enlighten me on the subject.

Thanks

[legoalan]

I would just like to add that I am looking to upgrade to a Skywatcher 200P dob but if it is plagued by bad collimation and I can't solve it then it would be very disappointing.

[Doc]

Basically collimation means aligning the telescope optics. Refractors can also be collimated but normally don't need as often as reflectors.

[brantuk]

Collimation is about lining up the light path between the primary and secondary mirrors and focuser tube so you get good sharp focus.

Astrobaby's guide is probably the best one to explain it all in detail

[bcfcciderhead]

Collimation is the alignment of the 2 mirrors (secondary & primary) so that the light hits both mirrors in the centre and this gives you the best possible view.

It is very important to get this correct and WILL make big difference in the viewing.

Collimation will NOT stay set once it has been done once, movement of the scope the odd bang will knock it off a bit, but dont be put of, it all sounds quite scary and can put a lot of people of (me being one) but once you do your relise it really is quite simple and after all if you do struggle doing it, you can't break the scope.

Loads of advice on here how to do and videos on youtube...it is simple and takes me about 5mins now.

Go for the 200p Dob, i have one and it's very good wont regret it.

[acey]

It's probably something you don't need to worry about.

Your scope has got two mirrors: they need to be properly aligned. Most scopes are well enough collimated from the factory. How much needs to be done subsequently depends on the size of the scope, the amount of hauling around that it gets, and the kind of observing that you do. A large scope that travels a lot and is used for high-resolution work (planets, double stars etc) is going to need very regular collimating. A small scope that gets gently carried in and out of a house and is used for low-resolution work (deep-sky) is not going to need so much. I used to use an 8" scope for deep-sky and occasional planets, often driving to dark sites. I collimated it once or twice a year. I now use a 12" and collimate it every time I use it. My advice would be to learn to observe before you worry about collimation. Whenever you start doing it, use a simple method such as a colli-cap.

As a comparison, think of a piano. It's tuned when you first get it, then slips out of tune. If you use some high-tech device then you'll discover it's out of tune after about a week. But does it need tuning? Depends if you can hear that it's out of tune. Once you're an experienced observer then you'll notice the difference between a well collimated scope and a poorly collimated one.

BTW the Skywatcher 200 is much like the 8" I formerly used. I didn't try collimating that scope for about a year after I got it, and collimated it rarely after that. But I could still see the discs of Jupiter's moons with it, if the air was steady enough. So I'd say go ahead and upgrade.

[bcfcciderhead]

must learn to type faster

[legoalan]

Thanks for all hte replies. I will youtube how to collimate a telescope. Just out of curiosity what is the difference between a laser collimator and an eyepiece one? Also is this collimator decent - Collimation - Cheshire Collimating Eyepiece ?

[acey]

That's the one that I use - does the job perfectly. With a laser you have a beam that goes from the focuser to the primary and back again. It's more prone to inaccuracy if it's not perfectly centred in the focuser. Stick to the Cheshire which is simpler and more reliable.

[legoalan]

Thanks for the advice I think will invest in one right now then =]

[Horus]

I just googled this.............. What is collimation anyway