Offset Mirrors???

[bullettooth]

Hey all. was just wondering if anyone knew if my secondary is meant to be offset or not on my scope.

Been trying to get my collimation spot on for a couple of days now. seems like when i can see my eye in the centre of the secondary holder (when looking through the focuser) i cannot see all three primary clips. and when i get all 3clips perfectly centered my eye is offset in the secondary holder.

i have made sure the secondary is perfectly circular (well, as close as) and there is the same amount of the focuser tube visible all around it.

so could this be that my secondary is meant to be offset or is it a problem with my focuser or are my spider veins not meant to be all the same lengths?

i can get my collimation close but its never spot on as stars always shoot off a bit.

someone please help its going my head in lol

thanks alot

Martin

[bullettooth]

just to add. i dont have a cheshire or lazer yet so just doing it best i can by eye and then doing a star test.

[bullettooth]

Nevermind. i think ive got it. its not totally perfect but its alot closer than it was

i think my focuser is out abit. thats the only thing i can put it down to now.

Clear skies

Martin

[faulksy]

i have heard of peeps having to shim there focusers, dont know if that helps

[bullettooth]

yeah it looks at though im going to have to do mine. as i can get my mirrors pretty much perfect but when the focuser is all the way out one of the primary clips is really close to the 'edge' if you know what i mean

[John]

The secondary mirror should be offset from the centre of the tube in fast newtonians, slightly away from the focuser I believe. This is built into the design of the Skywatcher secondary holder though so you don't need to do it yourself.