#1  
Old 09-09-2019, 08:54 PM
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Bobbyoutback
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Can't remove secondary mirror '''

I'm asking for help here as the scope I'm trying to get the secondary out of is new to me ' being a 12" GSO F/5 .

I can remove the plastic holder with the mirror but after then removing the one clip the mirror won't pop out ?

Hope they don't glue it in

Bobby .
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Old 09-09-2019, 09:55 PM
Saturnine (Jeff)
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Hi Bobby

You will probably find that the secondary is held in the holder by a silicon adhesive. That being the case, they can be a bugger to unattach, why do you want to remove the secondary mirror anyway.
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Old 10-09-2019, 12:17 AM
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Quote:
Originally Posted by Saturnine View Post
Hi Bobby

You will probably find that the secondary is held in the holder by a silicon adhesive. That being the case, they can be a bugger to unattach, why do you want to remove the secondary mirror anyway.
Hi , I wanted to see if i could remove it when needed , also the stock size is to big for ultimate performance .

Bobby
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Old 10-09-2019, 12:48 AM
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Ukastronomer (Jeremy)
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Quote:
Originally Posted by Bobbyoutback View Post
Hi , I wanted to see if i could remove it when needed , also the stock size is to big for ultimate performance .

Bobby
Two things confuse me

1. Why would you want to see if you can remove it without needing to remove it
2. How can it be too big
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Old 10-09-2019, 01:20 AM
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Quote:
Originally Posted by Ukastronomer View Post
Two things confuse me

1. Why would you want to see if you can remove it without needing to remove it
2. How can it be too big
Hello ,
My calculations say the supplied secondary is oversized for a 12" F/5 system ,
I can drop down a bit ( secondary size ) to get less visual defects by going to 20% central obstruction .

Cheers
Bobby .
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  #6  
Old 10-09-2019, 05:55 AM
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xelasnave
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Gcc
Quote:
Originally Posted by Bobbyoutback View Post
Hello ,
My calculations say the supplied secondary is oversized for a 12" F/5 system ,
I can drop down a bit ( secondary size ) to get less visual defects by going to 20% central obstruction .

Cheers
Bobby .
Work out the area difference between the two and you will find it is a very very small percentage of total area. And I bet the difference between your current secondary and you envisioned reeplacement will make no practical difference.
Alex

Buy more silver with your savings
Alex

Last edited by RB; 08-10-2019 at 08:00 PM.
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Old 10-09-2019, 06:17 AM
Startrek (Martin)
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No real benefit replacing the secondary unless itís pitted, scratched or broken
More bother than its worth
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Old 10-09-2019, 07:27 AM
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multiweb (Marc)
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If you really want to remove it I'd get a little piano wire and try to cut the bond at the back this way. That's the only way I can think of doing it unless the baffle can somehow be removed. Sometime it's screwed on.
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Old 10-09-2019, 08:17 AM
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Oversized secondary is good for photohraphy.. especially with "full frame" (or larger) sensor. And, difference between "ideal" and 20% larger obstruction is negligeable.
Visibility will be your limiting factor, not the size of the secondary.


Leave it be.


BUT.. if you really want another one for whatever reason, why not replace the whole spider and keep original mirror as spare?
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Old 10-09-2019, 10:15 AM
Saturnine (Jeff)
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Some wise words here, if it ain't broke, don't fix it.
As has been said, the difference of a few percent in secondary obstruction in anything but perfect seeing conditions will be almost unnoticeable.
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  #11  
Old 10-09-2019, 11:04 AM
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Thanks guys for all the advice , I will have to reconsider going smaller now .

Cheers
Bobby .
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