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Screws on C8 Orange Tube

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#1 JosephATL

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Posted 15 September 2020 - 10:48 PM

I'm looking to mount a guide-scope to my Orange tube C8.  Which of these screws is safe to remove to mount another shoe/braket?

 

 

 

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#2 scngc7317

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Posted 15 September 2020 - 11:22 PM

No Meade are Glued on Celestron are not 

 

IMG 3150


#3 Glenn Graham

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Posted 16 September 2020 - 11:47 AM

Your C8 looks similar to mine. I've had it apart, mounted, unmounted, etc. In my attached photo the screw pointed to with the yellow arrow fixes the tube to the rear cell. There are a total of four around the circumference and have a nut on the inside (you can see for yourself looking down the tube with a flashlight) - don't unscrew these. The screws identified with the red arrows were used to hold the scope to the fork arm (there are two matching 180 degrees on the other side of the tube). When unforked you could use these to attach accessories. The other screws (identified with the blue lines) were originally used for spotting scope and other accessories. One thing to be careful of is that your screws aren't too long as the holes are drilled through and a too-long screw could make contact with the mirror and damage it.

 

Whether glued or not, just be sure not to loosen/remove the four (marked in yellow) screws that attach the tube to the cell as you might end up with their nut floating around inside the OTA.

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Edited by Glenn Graham, 16 September 2020 - 11:55 AM.

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#4 JosephATL

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Posted 16 September 2020 - 12:10 PM

Glenn, this is great information.  Thank you for taking the time to make this.


Edited by JosephATL, 16 September 2020 - 12:10 PM.


#5 Glenn Graham

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Posted 16 September 2020 - 01:24 PM

You’re welcome. Good luck with the guide scope. Are you planning on imaging through the C8 at f/10? If so, that can be quite a challenge and you will need to minimize flex between you C8 and the guide scope. I would recommend attaching a plate rather than using a bracket at the rear. There are pairs of accessory screws on the rear cell that match up with single screws at the front  for a full length plate. I’ve always used an off-axis guider rather than a guide scope as there can also be movement of the mirror that you can only correct for if the guide camera is looking through the same optics as the imager.



#6 Don W

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Posted 16 September 2020 - 04:45 PM

Mr. Augustus. If  you remove or loosen the screws indicated by the yellow arrow, you can release a nut inside the OTA. They are there to hold the tube to the rear cell!!



#7 Augustus

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Posted 16 September 2020 - 05:15 PM

Mr. Augustus. If  you remove or loosen the screws indicated by the yellow arrow, you can release a nut inside the OTA. They are there to hold the tube to the rear cell!!

My mistake. I thought OP was only asking about the top screws.


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#8 Don W

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Posted 16 September 2020 - 06:12 PM

With any luck we learn something every day.



#9 highfnum

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Posted 16 September 2020 - 07:16 PM

i agree with glenn middle screw hold bottom to tube

here is mine with original finder

 

c82.jpg

 



#10 highfnum

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Posted 16 September 2020 - 07:17 PM

finder side

c81.jpg




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