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MicroFocuser for SCT


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I wondered if anyone was using one of these on an SCT? I quite like the idea of having a better focuser without attaching a crayford type. But, are they any good?

This is the one I'm looking at:

Feathertouch_FTM-CPC925.jpg

Any advice or insight welcome :)

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They are lovely, Mr Spock :smiley:

I've had one on a C11 and now one on an 8 inch SCT. Nice and compact and fine focus is a doddle, very smooth movement. For visual, it's all the focuser I need.

For DSO imaging, I am not sure but think I may remember some folks prefer a Crayford, can't remember if it was something to do wtih helping combat mirror flop?

EDIT: forgot to add that they are very easy to install :smiley:  Two minute job if you take your time!

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I will get one when I can afford one, using a dual speed focuser and then going back to the rubberised knob poking out the back of my mak makes me really appreciate the difference. I can see it is being a huge benefit especially for photographic reasons.

However I can see that Crayford would likely be the best upgrade as then you (I'm assuming) are moving much less weight to focus?

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Alma,

On the Celestron the way the focusing screw attaches to the rear of the mirror cell is completely different to the Meade.

It's a solid connection - the Feathertouch actually improves the fit of the focuser nut and gives good results.

The residual mirror flop - is always there - even with a Crayford.

The trick is to re-spread the grease on the baffle by running the mirror up and down the baffle (in and out of focus) this significantly reduces the small amount of flop.

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I had one on my CPC1100.  Superb.  Need a dab of grease every now and then though I found.  I am buying a C9.25 shortly.  I will be buying another one of these focusers for that too.  The 1/10 focusing is essential I think on a SCT.  I cannot see why Celestron don't do them as standard.

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Alma,

On the Celestron the way the focusing screw attaches to the rear of the mirror cell is completely different to the Meade.

It's a solid connection - the Feathertouch actually improves the fit of the focuser nut and gives good results.

The residual mirror flop - is always there - even with a Crayford.

The trick is to re-spread the grease on the baffle by running the mirror up and down the baffle (in and out of focus) this significantly reduces the small amount of flop.

Yes, I know - I have one on my C8. I just wanted to remove any impression that microfocusers remove the problem of mirror shift - they don't.

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Alma,

On the Celestron the way the focusing screw attaches to the rear of the mirror cell is completely different to the Meade.

It's a solid connection - the Feathertouch actually improves the fit of the focuser nut and gives good results.

The residual mirror flop - is always there - even with a Crayford.

The trick is to re-spread the grease on the baffle by running the mirror up and down the baffle (in and out of focus) this significantly reduces the small amount of flop.

Spread the grease out - that an old 'fix' offered for the original Meade LX200 classic, unfortunately the modest improvement didn't last very long. When I took mine apart and re-built it I tried to fix as many of these issues as I could and for the mirror slider (running on the baffle tube) I made a new tube with adjustable ball bearings to take out any slop/play between the two. The whole thing looked like this:

psn00013_zpsa8d7d0c9.jpg

psn00014_zps1670a178.jpg

psn00015_zpsa26fa594.jpg

and you probably worked out from looking at it that when the two halves are screwed together using a very fine thread the bearings are pushed inwards by the wedging action. That's how it is adjusted for clearance. Here it is fully assembled.

psn00017_zps28219bd0.jpg

I spent a lot of time on that LX200 OTA fixing stuff that should have been done at the design stage. I'm pretty happy with it now but there isn't much of the internals left which hasn't been modified in some way or other!

ChrisH

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