Focus Cube 3 compatibility with different focusers

FocusCube v1 & v2, Zero, Motor Focus Kit (Universal or Zero)
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Joined: Tue Oct 25, 2022 1:32 pm

Focus Cube 3 compatibility with different focusers

Post by givememu1 »

Hello, I recently bought Focus Cube 3.

I tried to install the Focus Cube onto my telescope, but I came to some compatibility issue with the focuser on my telescope.

I own a CFF 140mm refractor equipped with 3.5" Feather Touch Focuser (model 3545B).
The shaft diameter of the coarse focuser knob is 6.5mm, and the couplers provided with the Focus Cube are 4, 5, 6, 7, 8mm, where non of them really fit with the 6.5mm shaft.

Previously, I have used 3 different motorized focusers previously, and all of them had the exact sized coupler.
On this particular FT focuser, I used Primaluce's Senso Sesto 2, which connects to the fine adjustment focuser knob, so I never knew it wouldn't fit.

Is there any way to get a fitting coupler, or any way to use the Focus cube with what I have now?

Furthermore, I tried to install it onto Baader Diamond Steeltrack Focuser, which I was planning to put the Senso Sesto 2 on.

This time, the coupler fits perfectly.

However, I couldn't really fit the mounting bracket onto the focuser unless I remove the tension adjustment knob.

The bolt diameter is bigger than the central cavity on the mounting bracket.
I really don't want to be removing the tension adjustment knob in this focuser because the tention knob is made of two parts.
The bigger one that you use your fingers to adjust the tension has cavity inside the bolt thread, which house a small rod that pushes against the focuser tube.
The inner rod does not come off even when I remove the bigger knob, because it's held inside.
If I were to remove it, unless I completely disassemble the focuser.
If it's left dangling, I'm afraid it might have bad impact on the tension adjustment mechanism of this focuser.

The product description page on the Pegasus Astro website clearly indicate that the focuser cube 3 can be used on both feather touch focusers and steeltrack focuser. (but I coundn't figure out with years of experience in astrophotography...)
How did you install the Focus Cube onto the focuser when you were testing?

I bought the Focus Cube because I had good memories with your products and am currently using Advanced powerbox, ultimate powerbox, uranus meteo sensor and Nyx-101 mount.

I hope there's something I can do..

Best Regards,

Dae-Woong Hwang
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