OO Newtonian OTA's and Mirror removal

[Mr Fiery Jack]

I few weeks ago I bought a gallon of distilled water with the intention of cleaning my Europa's primary. I unscrewed the three screws that hold the end plate which holds the assembly but the tube is fixed tight to it. Has anyone cleaned an OO dob mirror? Maybe I have missed something?

[John]

When I had an OO Europa I stood the tube upright on the mirror cell, unscrewed and removed the 3 screws holding the tube end cover / mirror cell unit onto the tube then lifted the tube carefully straight up and away from the end cover / mirror / mirror cell. If yours is the same design that mine was that should work.

Mark the tube and end cover first so that you put the mirror and cell back oriented the same way.

[NGC 1502]

Yes I've removed the primary cell from my early model OO Dob, I'm guessing it's the same as your Europa. Best to place the tube on a sofa with the mirror end protruding a short distance from the end of the sofa. That way the tube cannot take a dive when the weight of the mirror & cell comes free.

Having removed those 3 external screws, only friction is keeping the mirror cell in place. Maybe someone could hold the tube while you pull the cell free. Make sure you don't rub the mirror surface on the end of the tube while you pull it firmly off.

Hope it goes well, Ed.

[NGC 1502]

Edit - duplicate post removed, Ed.

[Mr Fiery Jack]

OK thanks chaps, I'll give it another try. The scope is 8 years old now and could use a clean I think.

[Mr Fiery Jack]

Sorry, double post.