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Double Stack Stuck on Lunt Objective Lens?

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#1 phemmert



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Posted 27 May 2024 - 01:53 PM

I have a new Lunt 60 with the double stack, and decided to add the stack to the scope today. I screwed it into the objective lens on the scope - just light finger tight - and now it will not come off.


Have anyone else experienced this? 

I'm in Tucson and it will be easy to bring it to Lunt for some assistance, but curious in the meantime if anyone else has experienced this, and if so, what you did to get them apart?

#2 MalVeauX


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Posted 27 May 2024 - 01:54 PM

If it's snug, has sand in the threads, and gets hot, metal expands. It just needs a turn with assistance. Strap wrench does it without marring it.


Very best,

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#3 Highburymark



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Posted 27 May 2024 - 02:12 PM

I have double stacked 70mm Solarscope filters which I use with my TV85, via a machined adapter. After a couple of years’ use, the inner etalon/filter became completely stuck to the adapter, which meant I couldn’t tune it at all. It had to go back to the factory - now I’m careful to keep everything relatively loose. It also allows me to vary the position of the filters by slightly unscrewing them for best contrast - this is sometimes known as ‘clocking’

#4 hamers


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Posted 27 May 2024 - 02:25 PM

I have the large (LS100FHa) 100 mm etalon that has very fine threads on it and have had similar issues.  Occasionally I get some spray Teflon, spray it into a Q-tip (well away from the etalon) and then use the Qtip to apply a little bit to the male threads.  I let it dry for a hour or so.  That has helped a lot.  

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#5 bigdob24



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Posted 27 May 2024 - 03:48 PM

I do exactly what hamers does. 
Im always careful not to screw the pieces together tight, they can be difficult to unscrew

In fact after reading this it’s been awhile since I’ve treated my threads , a good project for a cloudy day.

#6 SeymoreStars



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Posted 27 May 2024 - 04:38 PM

All good suggestions. Like Marty I use something like this - https://www.amazon.com/dp/B0CMGLRNL4


Worse than the front mounted etalon getting stuck is the Hyperstar getting stuck. A set of strap wrenches is in the observatory.


Note: this is what I use - https://www.harborfr...iece-69373.html

Edited by SeymoreStars, 27 May 2024 - 04:43 PM.

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