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JMI Motofocus mod


cgarry

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I originally bought a JMI Motofocus for my 6SE many moons ago. To fit it you just remove 2 of the screw from the focuser, pop the Motofocus onto the focus knob and screw in place with the screws there were removed earlier.

This is a great piece of kit allowing very accurate focusing without causing the the OTA to shake. The only downside is that once it is fitted all focusing needs to be with the Motofocus. This can be slow if the focus knob needs to be turned multiple times and a disaster if the battery runs out.

When I bought my C9.25 I was very pleased to find the focuser was exactly the same as with my 6SE and I duly moved the Motofocus over to the C9.25. It worked perfectly allowing perfect focus for observing, webcam imaging and DSO imaging. The main issue I have comes when adding or removing a focal reducer, meaning the focus knob needs to be turned many times which can take over a minute with the Motofocus.

Anyway, today I finally made the effort to look at improving this and came up with a pretty simple solution that does every thing I want.

Some pictures:

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JMI Motofocus.

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JMI Motofocus with Velcro on the bottom.

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C9.25.

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Close up of C9.25 with matching Velco strip.

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C9.25 with Motofocus pushed on.

Now the Motofocus cam be fitted and removed in seconds and still works exactly as well as when it was fixed to the OTA with screws. The reason this works so well is the Motofocus naturally fits securely onto the focus knob and the purpose of the Velcro is just to stop the Motofocus from turning rather than hold it in place.

Time will tell how well the Velcro lasts, but replacing it is hardly a complicated job!

Cheers,

Chris

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Very Nice Mod Chris. I read this with interest as I am contemplating putting an AutoFocuser on my C9.25. I had looked at First Light Optics - SkyWatcher Auto Focuser at £45 but apparently it won't fit :-(

Not sure I want AutoFocusing that much to spend £145 on the JMI though but thanks for the info at least I know it can be done should I win the EuroMillions on Tuesday :-)

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Very Nice Mod Chris. I read this with interest as I am contemplating putting an AutoFocuser on my C9.25. I had looked at First Light Optics - SkyWatcher Auto Focuser at £45 but apparently it won't fit :-(

Not sure I want AutoFocusing that much to spend £145 on the JMI though but thanks for the info at least I know it can be done should I win the EuroMillions on Tuesday :-)

Yes, they are ridiculously expensive for what you get, probably 10x what you would pay if they were not astro related! However, they they do their job very well.

Chris

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  • 3 years later...

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