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How often do refocus

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#1 iwols

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Posted 23 January 2022 - 08:10 AM

Hi after years of focusing and using that setting for the session on every filter I've realised that I neeed to refocus more often as well as every filter, just wondered what you do.. Thanks

#2 terry59

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Posted 23 January 2022 - 08:28 AM

Every 1 degree F for the FSQ-106, 2 degrees F for the SV70T


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#3 ChrisWhite

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Posted 23 January 2022 - 08:35 AM

I refocus on filter change (Or use offsets) and/or every 1 hour for both my scopes (130 and 92).  My gear lives outside in an observatory though so it's basically always at ambient temp.  I open the roof at least an hour before imaging. 


Edited by ChrisWhite, 23 January 2022 - 08:35 AM.

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#4 NMCN

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Posted 23 January 2022 - 08:35 AM

I have the same scope you have and I refocus every 1 degree C and on every filter change.


Edited by NMCN, 23 January 2022 - 08:36 AM.

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#5 aaube

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Posted 23 January 2022 - 09:52 AM

Every 5 frames (normally 10 min. subs) and, on filter change / every 1.5 C.


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#6 don314

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Posted 23 January 2022 - 07:51 PM

Every 1 degree F, every hour, after every auto-center (100mm f/5.8 refactor)

I started doing every hour after a bad experience at a dark site.  It did an auto focus based on temperature, but apparently through thin clouds, so focus was off.  The clouds cleared but the temperature was stable, so no new auto focus. Ended up with 6 hours a out of focus data at my dark site.



#7 Sacred Heart

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Posted 23 January 2022 - 08:07 PM

I guess I'm the odd ball,  I refocus every 10F I don't change filters in the cold. I have only 1 filter, Ha.  I either start out using it or not.  Joe



#8 dswtan

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Posted 24 January 2022 - 02:06 AM

Every hour, and/or every filter change if less; also after a meridian flip. 



#9 squarefrustration

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Posted 24 January 2022 - 03:08 AM

Every 1 degree F, every hour, after every auto-center (100mm f/5.8 refactor)
I started doing every hour after a bad experience at a dark site. It did an auto focus based on temperature, but apparently through thin clouds, so focus was off. The clouds cleared but the temperature was stable, so no new auto focus. Ended up with 6 hours a out of focus data at my dark site.

That is like "scary stories you share by a campfire" level material! Had a bad focus experience myself recently, but only lost 40min


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