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PLL dovetail

Rainbow Astro RST-135 Rainbow Astro RST-135E Equatorial Mount Equipment
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Dunk avatar
Dunk avatar
Hey folks,

I'm close to pulling the pin on an RST135E. Since the mount doesn't come with a dovetail, and I already own a PLL "Medium" dovetail clamp I'm hoping to save some pennies and am wondering if anyone else can confirm this will work?

From my research it looks like there's a 30mm gap between the screws on the mount - which I think would allow the PLL clamp to fit.

Many thx.
Alex Nicholas avatar
Alex Nicholas avatar
Unfortunately, looking at the PLL clamp diagram, I don't think it will.

The two slots would be your best bet to make it work, but they are 36mm apart at their minimum distance, which is too far for the RST135 (if it is 30mm apart as you say) and the slots themselves only have 23mm of variability, which obviously falls short of the required 30mm. So you can't do an offset clamp fitting either. 

I looked at the PLL plate for my Avalon Instruments M-Zero too, and found the exact same issue. There simply is not a clamp on the market that provides the hole spacing I need with the Avalon Mount, So I'm looking at $350 minimum to get the Avalon Instruments losmandy plate (which I think I'm just going to not bother, and stick with Vixen clamps on the mount. 

Obviously with the RST135, you don't have the option of not buying a clamp. 

Alex.
Helpful
Alex Nicholas avatar
Alex Nicholas avatar
Just realised who you are ;) AvalonDunk from IIS ;)
Dunk avatar
Dunk avatar
Alex Nicholas:
Unfortunately, looking at the PLL clamp diagram, I don't think it will.

The two slots would be your best bet to make it work, but they are 36mm apart at their minimum distance, which is too far for the RST135 (if it is 30mm apart as you say) and the slots themselves only have 23mm of variability, which obviously falls short of the required 30mm. So you can't do an offset clamp fitting either.

Oh, I totally missed that in the diagram! Many thx - looks like you've answered my question ;-)
Dunk avatar
Dunk avatar
Alex Nicholas:
and the slots themselves only have 23mm of variability, which obviously falls short of the required 30mm. So you can't do an offset clamp fitting either.

What if I were to use the centre hole and then one of the slots? If I have 23mm of distance in the slot, then I only need 7mm more - which it looks like there is more than enough?

Alex Nicholas avatar
Alex Nicholas avatar
I didn't consider the center hole… silly me! 

Yep, that will work!