Aftermarket Focussing of a Mak?

[Mike21 (Michael)]

Hello All,

I am the proud new owner of one of Andrews' heavily discounted SW Promak 180's. Many sites have suggested that focussing a Chinese Mak can be a tad agricultural: bugger-all sophistication. The focussing mechanism is somewhat remote in feel and in the opposite corner of the Galaxy to the feel of my Williams' focuser. Williams, however, do offer a cassegrain, one-size-fits-all focusser for $300. Has anyone used one? If I choose to fit one, will this mean that my scope has two focussers; one that moves the primary mirror and one that moves the diagonal? If so, is there an easy way to lock the primary mirror to minimise shift?

Ta, Mike.

[qld]

Originally Posted by Mike21

Hello All,

I am the proud new owner of one of Andrews' heavily discounted SW Promak 180's. Many sites have suggested that focussing a Chinese Mak can be a tad agricultural: bugger-all sophistication. The focussing mechanism is somewhat remote in feel and in the opposite corner of the Galaxy to the feel of my Williams' focuser. Williams, however, do offer a cassegrain, one-size-fits-all focusser for $300. Has anyone used one? If I choose to fit one, will this mean that my scope has two focussers; one that moves the primary mirror and one that moves the diagonal? If so, is there an easy way to lock the primary mirror to minimise shift?

Ta, Mike.

i have an 8 inch mak and didnt like the mirror shift when using the focuser provided, so i put on the visual back a bintel sct focuser and a diagonal and works just fine,you first ocus with original focuser to get in the ballpark and then moove over to the sct focuser and you get a finer result and no mirror shift.

[Mike21 (Michael)]

Thanks QLD. At least I know I have options now too.