#1  
Old 09-09-2019, 08:54 PM
Bobbyoutback's Avatar
Bobbyoutback
Registered User

Bobbyoutback is offline
 
Join Date: Oct 2009
Location: Broken Hill
Posts: 361
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 .
Reply With Quote
  #2  
Old 09-09-2019, 09:55 PM
Saturnine (Jeff)
Registered User

Saturnine is offline
 
Join Date: Jul 2008
Location: Wollongong
Posts: 2,134
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.
Reply With Quote
  #3  
Old 10-09-2019, 12:17 AM
Bobbyoutback's Avatar
Bobbyoutback
Registered User

Bobbyoutback is offline
 
Join Date: Oct 2009
Location: Broken Hill
Posts: 361
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
Reply With Quote
  #4  
Old 10-09-2019, 12:48 AM
Ukastronomer (Jeremy)
Feel free to edit my imag

Ukastronomer is offline
 
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,381
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
Reply With Quote
  #5  
Old 10-09-2019, 01:20 AM
Bobbyoutback's Avatar
Bobbyoutback
Registered User

Bobbyoutback is offline
 
Join Date: Oct 2009
Location: Broken Hill
Posts: 361
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 .
Reply With Quote
  #6  
Old 10-09-2019, 05:55 AM
xelasnave's Avatar
xelasnave
Gravity does not Suck

xelasnave is offline
 
Join Date: Mar 2005
Location: Tabulam
Posts: 16,866
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.
Reply With Quote
  #7  
Old 10-09-2019, 06:17 AM
Startrek (Martin)
Registered User

Startrek is offline
 
Join Date: Dec 2017
Location: Sydney and South Coast NSW
Posts: 5,990
No real benefit replacing the secondary unless it’s pitted, scratched or broken
More bother than its worth
Reply With Quote
  #8  
Old 10-09-2019, 07:27 AM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
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.
Reply With Quote
  #9  
Old 10-09-2019, 08:17 AM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,932
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?
Reply With Quote
  #10  
Old 10-09-2019, 10:15 AM
Saturnine (Jeff)
Registered User

Saturnine is offline
 
Join Date: Jul 2008
Location: Wollongong
Posts: 2,134
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.
Reply With Quote
  #11  
Old 10-09-2019, 11:04 AM
Bobbyoutback's Avatar
Bobbyoutback
Registered User

Bobbyoutback is offline
 
Join Date: Oct 2009
Location: Broken Hill
Posts: 361
Thanks guys for all the advice , I will have to reconsider going smaller now .

Cheers
Bobby .
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 11:54 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement