Quote:
Originally Posted by mldee
Marc, am I correct in assuming that the cork and rubber mirror attachment ring is now assisted by the bonding material you used to hold the mirror to the new plates, so that there is no flop? Sounds very interesting.
The reason I ask is that my "remote focussing" concept, using a rear-mounted Crayford moving an internal tube attached to the mirror assembly, might not then be needed if I just emulated your attachment bonding. Seems simpler.
My approach also probably removes the ability for the scope to operate in normal mode, as the focus tube would be internal to the baffle tube, partially blocking it. I'll use my RC8 for longer FL stuff, so no concern to me.
Finally, do you think it would be a relatively simple engineering task to machine three 120deg radial lengthwise slots about 5mm wide by (say) 50mm long in the baffle tube for (say) 4mm diam focus attachment points to connect to the inner (Crayford-attached) mirror-push-pull tube? Since the baffle tube basically provides all the mirror support and movement dimensional accuracy, damaging it would be a no-no. How does it attach to the rear OTA plate, I can't see from the outside?
Sorry for the endless questions. What I'm trying to ascertain while it's still fresh in your head is whether I should proceed with my concept or just bond up the mirror for rigidity and concentrate on motorising the existing FT focuser.
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Good points being made here.
May I ask what advantage you see in having a rear crayford with a drawtube extension going up inside the baffle tube? I'm trying to picture this and seem to end up with the image of an unnecessary obstruction to the light path that doesn't give any added benefit.
A good crayford on the rear end is what I use now - using the original focus knob for coarse focus and thereafterusing only the crayford for fine tuning - requiring a travel of only a few mm either way.
And MArc, I can't picture what you have done. Any chance of a bit of a graphic?
I'm happy to have this discussion continue here without a new thread being opened.
Peter
Peter