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Hi Folks, I have one Focus Cube en route, I have two scopes i use equally, a 115 Triplet Refractor (805mm focal Length), Aluminium tube and 8" Ritchey Chretien (1600mm focal length) Steel Tube.  and here is my conundrum, ? Which one do i fit it to, I cannot reconcile in my mind which would benefit the most given the expansion rates of the Materials and focal lengths.  or am i over thinking it , chip in folks if you've got any thoughts, or better any experiences ... gary

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  • 2 weeks later...

Just thought of another alternative, if you have a Pegasus power box then you could get a Lakeside motor focuser for about £90. You'll just need a bracket to mount it and a shaft coupler. Lastly a cable to connect it up.

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Thanks for chipping in MarkAR,

1) reconfiguring my equipment may well be what i do, I go thro spells on using the RC8 or the Altair Astro 115EDT.

2) I guess doubling up on everything is an option but not for free. This focus cube works in concert with my UPBv2 so there is that valid option to purchase a second lesser expensive Pegasus Motor Focus Kit v2 Universal kit  and end up with one on both OTAs.

My initial motive for the question is to gauge the benefits of a Focus cube as it is a new device to me and thus i did not want to be disappointed with what it can do. give it the best chance to impress.

many thanks ... Gary

 

 

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I have a focus cube; I  fitted the supplied bracket to a separate dovetail itself fitted to the top holes on the rings of the refractor. I bought in a timing belt pulley with the same pitch as the thumbwheel on the focuser and use a timing belt to connect them.  On the "upper" dovetail I also have the guide scope, power distribution box, usb hub  and dew heater controllers. The upper dovetail is attached with thumbscrews. I made this assembly to be deliberately modular in nature so I don't have to set up the entire imaging rig in one go. Also, when the muse is upon me, so to speak; I can leave the upper dovetail off and just do a bit of boggling.  

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folks, just an update, in the end i decided to fit the Pegasus Electronic Focuser to my 72EDF Rig whilst i am still learning with it, it was a little easier to attach and so i will have a play with it on that setup for a while. Also, to be honest I need to get my head around all the settings and terminology associated with Auto focusing, maybe it's easy but the penny has not dropped yet. 

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Early experiences:

hi,

a couple of things that caught me out in deploying the Pegasus electronic focuser.

1) firstly, it made some horrible noises to start with because I had incorrect settings for max speed, I have this running through a Pegasus UPBv2 and although I use NINA for my sequencing these settings were made in the UPBv2 dedicated Application, I had ‘starlight….’ set and it should be ‘Pegasus default’, also checking the ‘rabbit’ recommended.

now whisper quiet.

2) secondly I got a bit confused when setting the steps to 5755 ( see focuser specification for one rotation ) and the electronic focuser only rotated 180°., all down to these focuser cubes employing half step drives, effectively doubling resolution. 11510 gets you a full rotation.

 

image.png.7417b5da7daf0efbdad2e783034a8321.png

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Success I think, did a bit of Maths to determine my Step size, established 'in-focus' as best I could by eye then final clamp of the Focuser. I then used NINA autofocus and let it run through its routine to state I was 600 Steps off (which i think equates to about 19° on the coarse focus knob). Image looked good so i will resist the temptation to tinker any further.

image.png.46018783bf1e585c34b1f6cc319d0409.png

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