Problems with GSO crayford :( ....

[elusiver]

Well.. first night tonight with the crayford in action, and I've having a few issues with it. I can't seem to get enough travel to focus with the 9mm or 15mm barlowed, the 9mm is right at the end of the travel. Has anyone had this issue with the 8" before? I've heard that you can move the primary, would this help? Is it hard to do?

any suggestions greatly appreciated.

thanks,
el :)

[Starkler]

Not enough inwards or outwards travel ?

Im guessing insufficient inwards travel, meaning that the path from primary to eyepiece is too long. Check that your secondary mirror is properly positioned under the focuser first, then you may be able to get a few more mm by loosening the main collimation screws on the primary cell. Be careful you dont go too far and unscrew them right out of the mirror cell.

[rmcpb]

I'm having no problems with my GS Crayford. It appears to have approximately the same travel as the R&P I replaced so I would be looking at the position of your primary due to repeated collimation creep. You may have to move it up or down the tube, depending on whether you have too little in travel or out travel.

Cheers

[elusiver]

thanks for the replies.. it's actually outwards travel.. but i'll try moving the primary out more.

thanks.
el :)

[ving]

hi el, is it for all of your EPs or just one?

[elusiver]

using the 9mm it focuses just before the end of the outward travel... anything under 9mm, i.e barlowing the 9mm or 15mm i just don't have enough outward travel.

el :)

[Starkler]

Before you do anything else, undo the bottom of the two screws on the underside of the crayford. The top one is to adjust focus tension and the bottom one is a focus lock. This focus lock can cause the drawtube to not fully extend if it is part way in.

[elusiver]

ohh ok thanks for that starkler.. that may be it.. i was playing with them before the sun went down to see what they did :P...

el :)

[ballaratdragons]

Any luck yet Ellex?

[elusiver]

still at work mate!!! will give it a shot once i get home.. haven't even checked if it's cloudy outside yet.. knowing my luck it probably is :(

el :)

[ballaratdragons]

:thumbsup:

[elusiver]

starkler.. u are a champ!

it was the focus lock knob.. she goes right now :) got the scope out at the moment cooling down.. but got a quick look and focused on jupiter no probs..

el :)

[ballaratdragons]

Our Geoff!!!! :clap: :clap: :clap:

Ain't bad is he! :thumbsup:

[Starkler]

:ashamed: Aww shucks guys !

This is the biggest weakness I think with this crayford.
With mine it seems any pressure whatsoever from the focus lock screw causes loss of about half of the barrel travel. I leave mine totally loose but the danger then is loosing the screw as I almost did on one occasion when it fell out into the grass. :doh:

[rmcpb]

Great to know this little problem. Will keep an eye on it for my focuser. Thanx :)