Skymak focuser problem.

[banjaxed]

I am thinking of adapting an auto focuser to fit my Skymak 127 and was trying to remove the focuser knob which proved to be very difficult, I didn’t want to use brute force so I left it as it was and went back to the drawing board. The next time I used the scope I noticed that to get focus I needed  to push the knob in towards the body as it was backing out about 2/3mm. Any help or advice would be greatly appreciated.

[nightfisher]

sounds like you need to get some local to you to have a look at it, if your near halifax welcome to bob it round at some point, or post some pics of the focuser

[banjaxed]

Thank you very much for your offer but I live near Southport which is a good distance way. The focuser looks like normal it’s just when you turn it to focus, the knob backs out from the body by about 2/3 mm. If the knob is pushed back in it will focus but it is a bit of a nuisance. Do you think I might have done some damage by trying to ease the focuser knob off ?

Edited August 18, 2019 by banjaxed

[banjaxed]

Can anyone tell me if there are any places in the north west of England that might be able to help me with this problem as it looks like I might have inadvertently damaged my focuser.

Edited August 18, 2019 by banjaxed

[banjaxed]

Any suggestions ?

[knobby]

Did you maybe miss the grub screw at 39 mins on this video ...

https://www.youtube.com/watch?v=im7DV2O4Eh8

 

[banjaxed]

Thank you for the suggestion but I have tightened both the Allen screws and it makes no difference. It looks like I might have to send it to someone for repair 🙁

[JamesF]

I'm not sure how that could happen, unless the focuser knob isn't properly engaged on the spindle.

Internally the spindle is threaded and passes through a threaded hole in a plate fitted to the mirror carriage.  Turning the spindle moves the carriage backwards and forwards.

Does it feel as though it's just the knob moving back and forth when you push it back in, or the spindle as well?

James

[banjaxed]

Hi James,

 It’s hard to tell but unless I push the knob in towards the body it will not focus.

[JamesF]

Were it me I'd probably unscrew the entire rear cell from the rest of the OTA at this point so I could have a look at what was happening inside, having previously stuck a bit of tape over the join and cut it along the join with a craft knife (just to make sure it goes back together in the same orientation, though I don't think that should really be a worry in this case).

James

[banjaxed]

Thanks for your input James. Pardon my ignorance but I thought the screws on the rear of the OTA were for collimating but they are obviously not.

Do you know which screws to undo to detach the rear cell, is it the small ones or the larger ones ?

Maurice.

[johninderby]

Best have a read of this fpr an explanation of what the screws do.

http://www.company7.com/library/orion/Inst_makcasscollim.pdf

I think rear cell simply unscrews but you will probably need a strap wrench to shift it. There is also a large rubber O ring arpind the rear cell which pften breaks when removing the rear cell.

[banjaxed]

Thanks for that info John, I have been in touch with FLO and they want me to send it to them for repair.

This might be the cheapest option in the long run as I might do more harm than good.

[nightfisher]

It is sounding like best idea to send it to FLo and get it sorted correctly