What tool for collimation

[spaceboy]

While I agree some laser collimator's are well designed (at an above average cost) the majority of laser collimator's are single point with out grid and given the alternative in that price range a Cheshire is hard to beat IMO.

[Damo636]

Hmm....I have both Cheshire and Baader Mk 3;for the record,you can check the secondary with the Baader Mk 3,and you can see the laser dot on the screen while doing the primary without dashing to and fro from the eyepiece. With my Skyliner 200p with a good solid focusser,there is no flop and wobble,and the laser produces the goods;I used to be a non-believer,but am now convinced by the laser.

The laser is indeed used to align the secondary with the primary centre spot. The trouble is though it can still do this even if the secondary is way off centre! This is where the collimation cap or cheshire come into play. If the secondary is not centered in the focus tube first the collimation will never be right. Don't get me wrong, i think the Baader is a cracking piece of kit and i use it all the time but imho it cannot completely replace the humble cheshire.

[russ.will]

As a collimation n00b (it was my post the OP referred to) the Cheshire route seems to have three advantages.

It's cheap, it won't require collimation as it's a solid lump of metal and finally, it's way better than no collimation at all.

As a £25 investment, it would seem to be a no brainer that sidesteps the laser-or-not debate. The important message lost in the background noise is simply to start collimating with something IMHO.

Russell

[Nova]

So is it possible to achieve perfect collimation with just a collimating cap? after alligning the secondary, I could then center the 2mm colli cap hole reflection into the centre of the dohnut on the primary?

[Moonshane]

some experienced people can collimate by eye and then do a star test to fine tune.

personally I would tend to rely on a Cheshire.

a collimation cap is OK for the secondary but not really accurate enough for the primary.

the problem is that is the hole is too small, you cannot see the secondary placement and if the hole is too big, you can get your eye placement accurate enough to do the primary. this is why you need a collicap with a larger hole and a Cheshire with a smaller hole (as far as I'm concerned anyhoo).

cheers

Shane

[Nova]

Cheers

[Telrad]

I use a Colli Cap and Chesire, seems to do the trick fine

[Treewick]

I have an Orion brand laser collimator that I purchased with my new telescope (Orion XT6 Dob). Unfortunately I came to realize after the first time I used it that the play in the sight tube was enough to render the laser useless. Even when tacked down with the tension screw the laser is just wobbly enough to swing the dot almost a full range to the left or right of the alignment grid. I ended up using the collimation cap to re-fix the collimation as I went through a full adjustment with the laser before I realized what was happening.

Is it possible to correct, reduce, or eliminate the play in the sight tube? If so how? Is it even worth it to try? Has anyone else had a similar issue specifically with an Orion XT6?

Also, would a collimation EP (Chesire) have the same issues given the play in the sight tube?

[spaceboy]

As long as you can correctly sight up the secondary you should be able to use a barlow with the laser to collimate the primary.

[Madhatter]

Is there any issues with the cheshire method when you travel to dark skys? it would seem best when your at home but at a dark site is the lazer method better?.

[spaceboy]

Moonshane has mentioned he uses his cheshire while shining a red light for illumination. At a dark site I prefer a star test to collimate the primary but a laser would make life easier that is if I knew for sure it was centered perfectly in the focuser.

[RikM]

At dark sites I still use the Cheshire, with a red torch shining on the reflective disk just like Shane described.

[Telrad]

laser collimators sometimes need colliamting

[Telrad]

At dark sites I still use the Cheshire, with a red torch shining on the reflective disk just like Shane described.

So do I. It's the only way I can collimate when it's dark.