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14" LX200GPS OTA Primary Mirror Refresh/Cleaning


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#1 Leartech

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Posted 15 March 2016 - 11:42 AM

I'm looking to clean up the primary mirror on a used 14" I have purchased.

 

I've looked for instructions on removing the thing from the OTA, and have a couple of sites that had pictures on how to do it, but not very clear on instructions.

 

This thing weighs 80 lbs, and I'm afraid the mirror may be a bit much trying to pull out of the OTA with my T-Rex arms...

 

Isn't there a way to remove the mirror cell and telescope back from the OTA itself? I had read that it was pressed in, but is that true?

 

Anyone that has done this and has suggestions would be greatly appreciated.

 

Thanks!

 

Bill



#2 Marcus Runge

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Posted 21 March 2016 - 05:48 AM

I have done this last year with my 12"LX200GPS.

  • Use examination gloves all the time
  • Consider you are doing a human surgery
  • Choose a mostly dust clean room, bath room is the first choice, clean it before you start.
  • Get a compressor with air gun and filter
  1. Remove Focuser and Mirror Lock
  2. Remove corrector plate (mark Position before)
  3. Carefully remove the Little lent-screw located at the top of the baffle tube.
  4. Pull the whole assembly out of the the OTA and place it on a clean upholstered surface
  5. Rinse with destilled water
  6. Rinse with Meade suggested cleaning solution
  7. Rinse with destilled water
  8. Spray the water away with compressed air
  9. Reassemble the opposite way

If, after reassembly the mirror lock doesn't lock, remove the mirror lock and turn the gear until the end stop has passed. This Can happen, because the gear sits fixed on the Surface and if you rotate the mirror, you lock or unlock the mirror. Usually with the knob you have a certain range to lock/unlock, there is an end stop for unlock on the gear, but without the knob you Can pass it.



#3 wayne_meade_monkey

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Posted 24 March 2016 - 03:49 PM

LX200 Internal wash bay

 

I needed to clean the primary mirror of the 12" LX200 but did not want to remove the primary mirror so I made this water proof internal wash bay for cleaning the mirror using a sheet by of 0.5mm thick plastic. It takes around 20 minutes to make and install the wash bay and 5 minutes to wash the primary mirror, it was easy and worked very well. (see the photos attached)

 

After carefully marking the corrector position remove the corrector

 

1. Measure the circumference of the primary mirror using a strip of paper or cardboard and mark a point, you don't want it too tight to slide past the primary mirror so add 3mm to the length.

 

2. Measure the circumference of the inside of the corrector housing at the end of the front of the OTA tube using a strip of paper or cardboard and mark a point, you don't want it too tight to slide past the opening so remove 3mm from the length.

 

3. Measure the distance from the primary mirror edge and the corrector housing.

 

4. Due to the primary mirror being larger than the corrector housing you will need to mark the plastic sheet from a central line to form a slightly conical shape, then add 100mm to the front to allow water to flow out of the OTA and add 50mm to the back to allow the wash bay to slide past the primary mirror to the rear cell. Also add a 10mm tab down one side to allow the sheet to be attached together with gaffa tape.

 

5. Carefully slide the internal wash bay through the corrector assembly and past the primary mirror

 

6. Do a similar procedure to make a tube to cover the baffle tube and attach to baffle using gaffa tape.

 

7. Place the OTA in a slightly downward position with a bucket on the ground at the front and carefully use a large syringe to wash the mirror with cleaning solution or mild pure soapy water then with another large syringe carefully wash the mirror with pure water and allow to completely dry then carefully remove the internal wash bay and replace the corrector to its original position.

Attached Thumbnails

  • internal wash bay 1.JPG
  • internal wash bay 2.JPG
  • internal wash bay 3.JPG
  • internal wash bay 4.JPG
  • internal wash bay 5.JPG

12" MEADE LX200GPS Schmidt-Cassegrain Telescope (UHTC)

Photo Gallery at http://www.astrobin..../WayneAnderson/

“Raise your eyes high up and see. Who has created these things?”
(Isaiah 40:26)

#4 MistrBadgr

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Posted 24 March 2016 - 06:12 PM

Hi Wayne!  Welcome to the Forum!

 

What you did is really slick!!!

 

Thanks for sharing.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma




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