Improving focussing control-Celestron 9.25" Go-to with XLT coatings

[SteveNickolls]

Hi,

I am looking into the options for improving focussing control on my SCT for the forthcoming 'season'. I use the 'scope for both visual and photographic uses (CCTV camera and DSLR). I have come across the Starlight Instruments Feather Touch Microfocuser Celestron 9.25 SCT retailing for around £259 which replaces the standard small standard SCT focussing knob, and the Baader Steeltrack SCT Crayford Focuser at £209 (and cheaper SkyWatcher Dual Speed Focuser For SCT Telescopes for £129). I would be grateful for comments/personal recommendations from members who have either of these already fitted on their 'scopes before I break the piggy bank open. I already have a Bahtinov mask to help when taking photographs.

Regards,

Steve

[m.tweedy]

I have both the featertouch microfocuser and also the moonlite crayford on mine. The feathertouch is very good but on the C11 there is still some mirror shift. I get a rough focus then fine tune with the crayford as it is not moving the mirror. Hope that helps (might hurt he wallet) I think if I was doing it from scratch (the feathertouch was already fitted to mine) I would keep the existing focuser and get a crayford as this achieves the fine focus needed.

[JamesF]

I think I'd agree. The focusing mechanism on SCTs and Maks is their weakest feature. It needs ripping out in its entirety and replacing with something else to really make it better. Far more sensible to add a new focuser to the back of the scope than fiddle about with something that isn't that well designed in the first place.

James

[Merlin66]

I have the 10:1 Feathertouch focuser on the C9.25. Works very well - no issues, no concerns.

Even if you fit a rear Crayford etc - you really still need some method of roughly focusing the main mirror and holding it from shifting.

The focuser mechanism in the Celestron is IMHO much better than the "linkage" system used in the LX200 etc.

Just my 0.02euro

[SteveNickolls]

Thanks guys for your accounts of experience and useful comments to add into my ruminations. One thought just popped into mind. I currently use a prime focus adaptor and Canon EOS 'T' ring to connect my DSLR camera to the SCT-with the Crayford in place I presume I would also need a different connector to attach the camera/eyepiece in the future?

[m.tweedy]

the best thing is to try some imaging BEFORE you invest in anything else. You may be lucky and have no image shift and not need anything else. If you get a crayford you will need something like this

http://www.firstlightoptics.com/adaptors/flo-2-inch-t-mount-camera-adapter.html

[SteveNickolls]

Thanks again Michael.

[perfrej]

If your 9.25 is the EdgeHD model there will be problems fitting an R&P at prime. At least that's what they told me. I have the Feathertouch micro and it is good. I have no severe shift problems and use a very light tightening of the mirror lock knobs after focusing, then check it again and maybe adjust a little. Basically, if focus changes a tiny bit when you tighten the lock knobs, just loosen them slightly and move focus knob a notch, then re-tighten. It usually gets perfect focus with zero to two iterations.

/p

[SteveNickolls]

Thanks perfrej, the 'scope is a vanilla SCT 'advanced' model not a more modern EdgeHD one so hopefully this will not be an issue ifI go down the Crayford path.

Cheers,

Steve

[BlueAstra]

I had a C8 SCT to which I added the microtouch focusser and later a SW autofucusser for remote control, as described here. The focusser was a great improvement on the original. Not sure why people get hung up on mirror shift. I generally slew to the target, which appears in the centre of the FOV, and focus with a Bahtinov mask. The image shift tends to be marginal, and if its a problem then I just recentre the image.

[ollypenrice]

I can't comment on the FT mirror-moving mod since I haven't used one. I have a Revalation Crayford on my own 10 inch SCT and use a Baader Steeltrack on Yves' resident 14 inch ODK. The Revelation is not bad but the Steeltrack is much more convincing.

Olly

[SteveNickolls]

Thanks BlueAstra and ollypenrice, I value your comments.

Cheers,

Steve

[Willarnold]

I changed my focuser to a Feathertouch. It was really easy to do, and I am very pleased that I did.

[SteveNickolls]

Cheers Willarnold for sharing your experiences with installing the Feathertouch.

[Carbon]

I have a C11 and up until recently had the C9.25 as well. Focus shift on the 9.25 was very minimal compared to the C11. I ended up getting the Feathertouch crayford for the C11 because the focus shift on that scope was rather annoying. It's a very nice focuser.

[SteveNickolls]

Thanks for this Carbon. I feel the pull towards a Feathertouch is slowly growing.

Cheers,

Steve

[usingen1]

I have a Moonlight CS with the internal option for the Fr 6,3  C9,25 and a feathertouch micro, pretty expensive but with the C 9,25 brand new i thought this would be the way to go since i have

 great results with the feathertouch with my C8

 

C8

C 9,25 moonlite focuser w/6,3 Fr - raci finder (Cel), star sense Avx mount + self built concrete pier (absolutely NO shakes) use head of avx with custom adapter- star sense  -

Canon EOS

[garryblueboy]

I found also fitting the feather touch simple and works great on my 9.25 Evo I had the crayford but sold it in the end as the feather touch did the job fine and is less of a weight problem when attaching accessories and big eyepices etc .