Colli cap limitations

[Tiki]

How well can a fastish (say f4.5) newt be collimated with just a colli cap and a standard focuser?

Thanks

[Tiki]

By standard i mean not with tons of back-focus.

[RonVen]

Take a look at; www.garyseronik.com/?q=node/169.

Ron

[Moonshane]

there's no difference between collimating an f4 or an f10 scope. you would be able to get it pretty close but you'd be better with a cheshire.

[AlexB67]

.....you'd be better with a cheshire.

....or wait, you may have Umadog on your case, did you mean a sight tube . In any case I just use the cap aka a Cheshire, but it is hard to do the secondary with that, but I feel it is good enough for visual for now, In intend to invest in a sight tube or combination tool at some point but do not feel an urgent need, it is that kind of tool that often commonly gets called a Cheshire fi I understand correctly. Even if my collimation is not 100% not doing imaging anyway. Probably it is close enough and the cap is okay for now.

I was actually surprised how close the collimation was to what is should have been when I did it first time, doing it just by eye having no tools at all, the primary just needed a tiny tweak when I got the cap, but the secondary is hard to judge with just a cap I find.

Star test looks pretty decent though I feel in my case ( as far as I know with limited experience thus far).

[umadog]

....or wait, you may have Umadog on your case, did you mean a sight tube .

Yay! Someone listened! :hello2:

[Moonshane]

ha ha quite right but I have in a way given up saying sight tube / cheshire and people worry they don't have the sight tube. you can easily check position and rotation of the secondary by using an extension tube with the cheshire (sight tube ).

[umadog]

ha ha quite right but I have in a way given up saying sight tube / cheshire and people worry they don't have the sight tube. you can easily check position and rotation of the secondary by using an extension tube with the cheshire (sight tube ).

True, but then they learn. You get problems either way, though: If you don't distinguish the two components then the term "Cheshire" loses it's meaning, which is worse. e.g. "A Cheshire is used to set primary tilt" moves different things depending on what you think a Cheshire is.

[Moonshane]

yeah, fair comment