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Newtonian Secondary Mirror Glue Question

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#1 jkevn

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Posted 19 June 2025 - 07:20 PM

I am storing my Sky-Watcher 12" collapsible dob telescope in my backyard shed, in Tucson, AZ. The temperature outside this afternoon reached 112 degrees today, and the temp inside the shed reached 125. Temperatures will get as high as this during the rest of June. I am worried about the glue holding the secondary detaching because of the heat. There is nothing in the manual about storage temperatures, and I don't know what kind of glue was used to hold the secondary. I'm keeping the tube near level to safeguard the primary In case it falls. Does anyone store this scope at high temperatures like this? Is this something to be worried about?



#2 Bob4BVM

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Posted 19 June 2025 - 08:33 PM

How does the sec holder attach to the spider hub ?

Most are a single center screw.  30 second job to unscrew the holder and keep it indoors when not in use.

IIWM, i'd be moving somewhere meant for humans :)


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#3 azure1961p

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Posted 22 June 2025 - 08:22 AM

I always assumed it was silicone but don't qoute me.  Frankly despite "glue" I'd have a very short fine chain attached to the secondary back (epoxy?) So in the event the glue failed the chain still keeps it from falling.  I'd say just remove the secondary altogether and leave the spider intact.

 

Pete


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#4 jkevn

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Posted 24 June 2025 - 05:01 PM

It turns out that my Sky-Watcher 12" newtonian secondary is supported by double stick tape, not silicone or other adhesive. According to SW technical support, the factory temperature specification for the tape is 80° C (176° F) max. So this should not be a problem.




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