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How to chose tube ring diameter for 120mm refractor?

Equipment Refractors
2 replies•72 views
Photon_Collector avatar
Photon_Collector avatar
Hi all, 

I am looking to replace the stock tube rings that came with my Askar 120 APO refractor with some beefier ones that are more compatible with a losmandy mounting plate. 

I am looking at these: https://www.highpointscientific.com/primalucelab-125mm-plus-support-rings-pllandu125p but I can't for the life of me figure out if they will fit snuggly on my OTA. 

Does anyone have some advice? Thanks!
Well Written Engaging
Photon_Collector avatar
Photon_Collector avatar
Realizing the obvious answer is just measure the diameter yourself…I don't have a ruler/tape measure on hand!
Daniele Borsari avatar
Daniele Borsari avatar
I found this drawing of the Askar 120 APO just by googling. The tube diameter where you would place the rings is 110mm. I almost certainly think that 125mm rings are too big,

PrimaLuceLab makes 105mm and 115mm rings, but not 110mm. I don't know which diam would be the best, maybe you should try to contact PrimaLuceLab and ask what's the best option.
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