Post by Chicago Astronomer - Astro Joe on May 29, 2011 23:23:18 GMT -6
C11 Modifications - Revisited a Year Later
May 2011
PART 1
May 2011
PART 1
The C11 SCT Beast sees a lot of action.
It's been a year since the last major dis-assembling of the SCT...
astronomer.proboards.com/index.cgi?action=display&board=ATM&thread=2760&page=1#12566
Transported across the Chicagoland area, we have attended to thousands of visitors since put to use in 2009. And that all takes a toll on performance and appearance. Looking at the Corrector Plate, it needs a cleaning just one year after the major cleaning project of last year...and there's a spider web inside the OTA.
Also, the exterior of the C11 and Tripod needs some attention. With nicks, dings and scrapes others have put on before I came into possession of it...I too have included my own scars of action.
Time for a make-over...and dramatic one.
This Mod will include installing two sets of crafted billet aluminum rings, dovetails, a temp gauge and new paint job.
I needed to wait till the warmer nights arrived, but this spring has been awful...not only for astronomy - with cold cloudy nights, but for any ATM projects. This week started out cold, but is ending up hot.
Time to start.
I bring the C11 OTA into the workshop and prep it to start the disassembly..but first some tunes....
Chicago Astronomer Joe is all updated with all the modern HI-FI systems...and selects an 8-Track...
I got a boat load of 8-Tracks from a dude who was getting rid of his stuff and haven't heard most of them. I select "America"...and we start.
I had noticed near the end of last observing season that the Corrector Plate looked dull...and indeed - had become grimy...
Not only is the grime "greasy", but we spot the Spider web that has been obstructing light from stars billions of light years away. Let's explore this grime...
The C11 is out in the open a lot - parks and the lakefront mostly, I assume that it collects airborne detritus ... from picnics, vehicles, Adler exhaust vents...and from smokers - Cigarettes, cigars, pipes...it all got to go somewhere. And considering I cap the C11 after each use and keep it bagged while she's sleeping, it's not something that is collecting when not in use.
- No Smoking signs will be put up for Chicago Astronomer sessions.
We continue....
Taking off the retainer ring...
We check around the edge of the C.P. and find no chips or cracks, but a potential situation was discovered...
Two of the cork spacers were missing and the glass C.P was resting bare onto the ring collar and retaining ring. Space on top, contact on the bottom.
Not cool...
Removing the C.P., we take a quick examination of the secondary, and other than flecks and dust, (mostly from the C11 foam packaging), it's not bad...
We will clean the optical drive train later, so for now, I pack it away in a trash bag and a clean pizza box I get from a friend...
With the C.P. removed, I get to see the Spider web closely....
The arachnid spun it's little web from the top inside of the OTA to the secondary housing.
I remove the JMI focuser from the visual back...
...And the Primary focusing assembly. A cinch from last year's project...
I needed to remove the "Speed Rails" I installed along both sides of the OTA in order to remove the collar. (The Speed Rails are a great mod to the C11. I can control the OTA securely with gloves in the winter and guide the scope easier than the old clunky way of nudging the tube. They also are indispensable for carrying and heaving the 24 lb tube up to the mount. All SCTs should have them installed as standard equipment.)
With the rails off, we remove the front collar..
It's pretty banged up. With paint chipped off, glue and other gunk, it's time to give it a fresh coat and bring it back to decent appearances.
Reaching in, I pull off the snap C-ring on the baffle and remove the heavy primary mirror...
Giving it a quick once over, it's not in bad shape. Minor cleaning is called for, but for now, I put it away for later...
The flocking I installed a year ago is holding up very well and the adhesive solidly strong. I use some tape to try and find the little spider that spun a web in my scope....
But all I find is a winged creature...long dead. and snuck in through the visual back opening...probably while breaking down the site after an observation.
Plug your ports quick kids...!
I had just intended to install the rings, dovetails, temp gauge and paint the front collar...but things have a way of dominoing and we go for total breakdown and separate all C11 parts from each other.
More in part 2......
)
For the color coat, I use the bigger spray gun for better uniform coverage...
