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Cleaning and Modifying the C11 Beast - Part 9: Installing the Corrector Plate and Closing the Tube


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Cleaning and Modifying the C11 Beast

By Joseph Guzmán

This article is part 9 in the How-To series “C11 Cleaning & Modification”:

  1. Part 1: Removing the Corrector Plate
  2. Part 2: Installing a Rail Carry Handle
  3. Part 3: Removing the Primary Mirror
  4. Part 4: Flocking the Interior
  5. Part 5: More Grab and control handles
  6. Part 6: Installing side control rails
  7. Part 7: Cleaning the optical surfaces - Primary Mirror
  8. Part 8: Cleaning the Corrector Plate
  9. Part 9: Installing the Corrector Plate and Closing the Tube

Part 9: Installing the Corrector Plate and Closing the Tube

Seems I like to work best at night , as I had time early in the evening to continue with the project, but it felt wrong with the Sun being out. Starting at 11:30 pm, I prepped to return the Corrector Plate back on.

Looking at the collar, it's seen a lot of duty, nicked, scuffed and paint coming off… it really needs a fresh refinishing and paint job - but not for this project.


Figure 9-1.

Perhaps in the fall - then I can blow out the inside of the tube.

I clean the front collar/cell… and it was quite dirty. The cork base still looked good and it slipped on nicely on the tube, with all the old and new holes aligning nicely…


Figure 9-2.


Figure 9-3.


Figure 9-4.

All my screws and hardware were safely organized in my little vial case, but I was confused on why there were two different size bolts in the same vial 2nd to last in line… (more on this later).

I bolt back on the clips and single screws around the collar and permanently attach the side control rails now…


Figure 9-5.


Figure 9-6.

Nice, solid and now more confident in carrying and guiding the C11… :)

I like to note what I did and when on my projects. Throughout my home are dates and signatures behind window sills, drywall and subfloors. This project is no exception and I write behind my Astro business card the project, date and sig…


Figure 9-7.

I place it under the front collar lip and covered with the mounting rail…


Figure 9-8.


Figure 9-9.

(More on those two different sized screws…

In a vial, I had four similar screws, but two were a bit shorter, but I did not know why. I installed the mounting rail on to the OTA, unsure why the discrepancy… but it was to be clear soon. Down by the Primary mirror side, I was screwing down one of the larger length screws for the mount rail, and noticed that the screw was heading for the lip of the mirror - with just a scant couple of millimeters to go before hitting it…!

And there was still some thread to go… dang!

I understand now. Shorter length screws Mirror side, larger ones up front.

Make a note kids… :'(

Next is the re-installation of the Corrector Plate, but first… some more cleaning with tape…


Figure 9-10.

… and some more…


Figure 9-11.

It looks good, but I'm sure some debris will find it's way onto the mirror when I close up… >:(

I remove the plate from the pizza box and give it a dusting. Still looks clean, but dust just settles everywhere… even a minute in the open, dust settles down. (Must learn not to shed skin cells so readily.)

I wanted to sign the Mirror before I returned it, but in all the excitement… I forgot. But, not this time, and I put my moniker along the edge of the plate…


Figure 9-12.


Figure 9-13.

I dig it.


Figure 9-14.

I brush off the rear of the plate again, (can't away from the damned dust), and quickly seat it in the cell/collar. Following the marks I made before I took the plate out, It looks good and in a similar position. I place the cork spacers back in…


Figure 9-15.

I clean off the ring holder and install…


Figure 9-16.


Figure 9-17.

Using just enough torque to have the screwdriver slip off the screw when tightened enough.

And there…


Figure 9-18.


Figure 9-19.

It's all put back together…


Figure 9-20.

I examine the beast… and yep..I got some dust behind the Corrector Plate and on the mirror… but some things just can't be helped…


Figure 9-21.

This took longer than I expected, but only because of the additional auxiliary enhancements. The actual cleaning was not as difficult as expected and the whole instrument is cleaner than it has been in years. I would like to have painted it, but I just wanted the project ended, as there are a host of other projects around the estate that needs my attention.

I'm hoping this scrubbing enhances the viewing, making good views great ones - and with all that haze and crud removed - just gotta be. There is a ever so slight haze on the primary mirror, but I will not attempt to remove that.

It's cloudy out now in Chicago, so a test run will have to wait… but glad it's over!… :P

Update on performance coming soon.


Figure 9-22.

Now… some deserved sleep.

The initial shake out session of the cleaned and modified C11 has been completed and can be found here: http://astronomer.proboards.com/index.cgi?action=display&board=StarParty&thread=2766&page=1


Figure 9-23.

Full narrative at the above link, but it needs serious collimation.

The newly installed handles and rails are great though…!




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