Revelation Crayford Focuser and base plate for 6" Newtonian

[Uplooker]

I truly hope someone can help me, otherwise i have made a complete fool of myself

I have purchased a Revelation Crayford focuser as shown here:-

Telescope House Revelation Newtonian Crayford Focuser Dual Speed

and a base plate:-

Base for Newtonian focusers for tubes with D= 160-205mm

to attach said focuser to a SW 6" F5 newtonian.

I detached the base plate that comes with the focuser and tried to fit the replacement base plate - it does not fit:confused:

The diameter of the hole in the base plate is 2-3mm too small.

Have I made an inexpensive mistake and purchased the wrong base plate or a more expensive mistake by buying the wrong focuser and base plate to fit to my scope.

I have read the various posts by johninderby

http://stargazerslounge.com/diy-astronomer/119323-fitting-2-focuser-skywatcher-150pl-newt-ota.html

All suggestions appreciated

[johninderby]

Hmmm....I wonder if they've changed the dimensions slightly?

I took a look at Telescope Services website and while they used to list this base to fit the Baader focuser they now offer a Baader focuser modified to fit the base.

I'll look into it tomorrow and see what info I can dig up.

John

[johninderby]

Well it now looks like there are two very slightly different mounting flange sizes. Some focusers will fit the slightly smaller diameter opening in the TS base-plate and some won't.

Apart from the focusers on TS's website that show the base-plate as an option, it looks like the replacement crayford for the Skytwacher MN190 will fit. Perhaps you could ask FLO to see if they could check the diameter of the mounting flange of the MN190 replacement focuser.

http://www.firstlightoptics.com/proddetail.php?prod=skywatcher_focuser_190MN

Of course this means you would have to return the focuser to TH but they're pretty good with customer service so it shouldn't be a problem.

John

[spaceboy]

I would like to bet if you took the base plate to a local fabricator they would drop it on the lathe and take that 2-3mm off in no time and only exspect a drink to cover their time. A sharpie marker will soon get it back to black.

Just a thought.

SPACEBOY

[johninderby]

It's only about 1.5mm off in dia. so it would be a very simple job for anyone with a lathe handy.

Begs the question why have two sizes of flanges that are almost the same?

John

[Uplooker]

Thanks all for your suggestions / advice, particularly John.

Why are base plates so hard to come by? Is there anywhere else I could purchase one, obviously, apart from Telskop Service. How would I know if it would fit?

[johninderby]

Thanks all for your suggestions / advice, particularly John.

Why are base plates so hard to come by? Is there anywhere else I could purchase one, obviously, apart from Telskop Service. How would I know if it would fit?

For some reason most makers of focusers seem to only produce baseplates that fit 8" scopes and over. The TS one is the only inexpensive one for a 6" scope that I've found.

Moonlite makes a base to fit one of their focusers to a 6" scope, but then there's the cost of the Moonlite focuser it's self. £££

I suppose the only guaranteed way to make sure a focuser would fit would be to get one from TS.

John