Advanced Newt Collimation With Cameras

[Guest AstronomyShed]

This is the result of a long and very enjoyable conversation with Doc on a forum I shall only refer to as the star wars bar, a long time ago, and he even gets a mention, so here's the method, I reckon this will get a fair bit of feedback lol :-

[media]http://www.youtube.com/watch?v=8ROvNH5uwDo

[Doc]

Thanks for giving me a mention Dion but all the credit has got to go to you, you put our idea into practise and made it work in a very simple way. As you say it is extremely accurate way to collimate. I've watched it three times now and I must say I'm impressed with the simplicity and accuracy of it, well done Dion on a great tutorial. It's a shame I haven't got a newt or dob anymore but when i get one I will be using this tutorial for sure.

[Guest AstronomyShed]

it was the result of input from the pair of us, without someone to bounce ideas back and forth with it wouldn't have got to this stage.

It works brilliantly Mick, double checked with a cheshire and it really does come out text book picture collimated, spider vanes aligned with crosshairs the lot, here's the strange one though, I actually found it easier to do my F4 Quattro 10CF using this method than I did on the 200P in the vid, i think it's possible that the big mirrors and aperture just grabbed more light and made everything easy to see, but from what i'd read i was expecting the F4 to be a mare to collimate, full procedure took about 10 minutes to complete.

At the end of the day, simplifying the procedure, it's just an adjustable digital cheshire, but that makes everything easy because it's on a screen. But hopefully now those people I keep telling that laser collimaters don't work will believe me lol IMHO the laser collimater is only good for one thing, and thats putting in a barlow to collimate the secondary or aligning the focuser. meaning that the massive expense of one of the so called 'self centering' collimaters is a total waste.

Edited February 20, 2012 by AstronomyShed

[Doc]

It is a great way to perfect your collimation but not everyone has access to video camera and a laptop while out observing so the next best thing is a Hotech laser colliator IMO. I must admit that I do have a hotech laser collimator and after practice and in conjunction with a collicap you can get the secondary very circular under the focuser, no where near as accurate as the video method as I have tried both but pretty darn close, unless you want perfection it is close enough for most folks.

Your idea is perfect for people with astrophotography set ups as they will already have a lap top beside them and cameras or prretty cheap, or someone who has a pier mounted set up and only need to do collimation once to perfect it.

As for the Quattro being easier perhaps you are getting better

[Guest AstronomyShed]

It's old age and the eyes Mick, in a Quattro 10" everythings bigger. I agree re using sight tube you can get close, but that's not what the laser collimater people say, they just say adjust secondary to get the dot on the primary and the secondary is now completed, and that's tosh, I bet there's loads of beginners out there who think they're collimated and really it's a mile out. And for primary, barlowed laser is unbeatable, and for that, centering isn't important.

What the camera does show though that you don't notice as much in a cheshire due to all the too-ing and fro-ing, is that the relationship between primary and secondary is very tight, I find with camera you need to go between primary and secondary at least twice.

[Doc]

They say that because thats what a beginner wants to hear, basic, simple and easy to read instructions. As you say adjust secondary to get the dot on the primary and the secondary is now completed. How much more simpler is that for someone who has just started out and who wouldn't know any difference between the two set ups anyway.

Beginners are quite happy to stick in a laser collimator or cheshire and follow simple instructions to get it collimation pretty good, as long as the view looks nice they are happy, it's not till you get to the semi experienced level that you start tinkering and trying to improve collimation.

And your set up is the ultimate in collimation, but then not everyone carries a laptop and camera around, in fact not everyone is bothered with perfection.

So yes while I agree that the laser collimator is not perfect and companies are wrong saying "adjust secondary to get the dot on the primary and the secondary is now completed" I can understand why they do it.

[Daz Type-R]

Nice compromise between the 2 camps Mick, I must admit I rushed out to get a laser collimator thinking it would do the trick, quickly learned it's not the case!

Thanks Dion for the excellent collimation method though, if I ever have some spare cash lying around then I will purchase a webcam for this very method but until then, i will have to put up with what I have.

As I am not into astrophotography (YET) I hope my (semi) collimated scope will do.

[Guest AstronomyShed]

Funnily enough, you can use a normal astro webcam with this method and collimate SCT's, for an SCT, use your normal astro modded webcam, do the same setup as in the vid with sharpcap and the mire de collimation, now point at a star (real or artificial) defocos to get the 'airy disk' and then colimate airy disk to center,