Cheshire collimator....long/short?

[Alanmads]

I'm just about to purchase a collimator for my scope and have read that laser collimators for beginners may not be the answer as they too need collimating. Therefore i have been advised that in order to keep it 'simple' (lol) a cheshire would be a good option.

My questions are as follows.....

a) Is this person talking gibberish or is what he says true?

Is there any difference between buying a long or short tube cheshire (other than cost)?

If it helps with the answers I have (for my sins) a Konusmotor 130 1000mm f8 (I think)

Cheers folks

Alan

[umadog]

Yes, a cheshire is a good idea.

A cheshire doesn't have a long tube. A sight-tube has a long tube. You are probably talking about a cheshire/sight-tube combination tool but it's hard to tell based on what you say.

[John]

While it is true that low cost laser collimators can often be out of collimation themselves, I don't think a laser collimator would work with your scope - I believe the Konus 130 F/8 has a correcting lens at the bottom of the eyepiece drawtube which means that the laser beam gets dispersed before it reaches the primary mirror.

So a cheshire is definitely the way to go.

[Alanmads]

(Umadog) With regards to the long/short cheshire, i have seen on several sites that they stock both which are just listed as 'cheshire collimating tool long tube, and cheshire collimating tool short tube.

Obviously i dont want to get the wrong one as they are over £20 a pop, small potatoes in the grand scheme of things where telescope accessories are concerned but 26 quid is still 26 quid lol

So the short tube is generally the norm then?

(John) Yes you are spot on with regards to my scope. IF i had on known this when i got it i would have made a different choice in scope but at the time i knew nothing about scopes at all as its my 1st ever one. (will know better next time though lol)

Thanks for your help guys.

(is it the short tube cheshire i should be getting?)

Cheers

Alan

[umadog]

I know they all call them cheshires, but they're all wrong. A cheshire is a tool for adjusting the primary mirror tilt. The long tube with the cross hairs at the end is a sight tube, for adjusting the secondary mirror tilt and rounding the secondary. Usually these tools are integrated into a combination tool. The distinction matters because if someone tells you to "use a cheshire to adjust the primary mirror" you may do different things depending on what you define as a cheshire.

I was wondering if the "short-tube cheshire" was a cheshire alone and the long tube was a combination tool.

[Moonshane]

best thing would be to put a link to the two you mean. in reality I am sure they will both be combination tools with different length tubes.

I actually have a cheapie Cheshire with no cross hairs which came free with a scope I bought ages ago. I use a home made collimation cap for initial alignment of the secondary and combination too for the fine alignment of the secondary and then the cheapie Cheshire for the primary.

I bet you'll be ok with either of your Cheshire's for all tasks. let us see the links though so we can be sure?

[rory]

best thing would be to put a link to the two you mean. in reality I am sure they will both be combination tools with different length tubes.

I actually have a cheapie Cheshire with no cross hairs which came free with a scope I bought ages ago. I use a home made collimation cap for initial alignment of the secondary and combination too for the fine alignment of the secondary and then the cheapie Cheshire for the primary.

I bet you'll be ok with either of your Cheshire's for all tasks. let us see the links though so we can be sure?

i too wondered if it mattered which length mattered. i was guessing that the short sighting tool was maybe to do with diagonals, i cant think of another reason.

heres what i think he's talking about

http://www.skysthelimit.org.uk/collimators.html

[Moonshane]

I use the cross hairs in one like the long one in the link for my secondary alignment (stage two) and one like the short one (that has no cross hairs) for my primary alignment. I have just newts.

I don't think in the end it matters as such; if you collimate your way, with your tools and get good sharp lunar/planetary detail at higher powers then there's nothing to worry about