Is collimation required after replacing focuser.

[Captain Rex]

I am looking at options on the Skywatcher 102 and 120mm refractors and considering replacing the standard focusser with the Dual-Speed 2" Crayford Focuser .

Will the OTA need to be collimated after the exchange?

Many thanks.

Marty

[MarkAR]

Shouldn't think so.

[johninderby]

The new focuser only has to be the tiniest bit out of line to throw off the collimation.so you should do a star test to check.

[johnturley]

I have some thoughts of upgrading the focuser on my Esprit 150 to a Feathertouch, but worried as to whether retro fitting one could affect the collimation, especially as when Es Reid checked mine, he told me that it was one of the best he had tested.

John 

Edited July 4, 2020 by johnturley

[johninderby]

A laser can also be used to check refractor collimation. A good collimated laser though. Print out a target to fit the objective..

Edited July 4, 2020 by johninderby

[wookie1965]

My Meade 127mm had a terrible focuser on it a friend gave me a Skywatcher dual focuser that needed tweaking. I also needed a an adaptor to make it fit.

I contacted Mark at Moonraker He said send the old and new focusers and plenty of measurements and diagrams and he would see what he could do.

He rang me about how much infocus I had to make sure the skywatcher would work properly said the Meade focuser was it out of a lucky bag  and said he would look at the skywatcher focuser.

6 weeks later rang me all finished with a price he had made the adaptor araldited the focuser in the adaptor and told me he had tweaked the focuser told me there was a ballbearing missing and a couple of small grub screws.

Sent it back to me I put it on and the view was terrible took the whole thing to Peter Drew brilliant bloke he looked through it and said I know exactly whats wrong the two pieces of glass at the front had been swapped around.

He took it apart and they where swapped them did a star test on a artificial star and it was bob on,  I brought it home checked collimation and it was collimated to perfection I was lucky I guess. 

Edited July 4, 2020 by wookie1965