I have long been disconnected from astronomy because of that I have good friends . A friend gave me a C14 optical tube, for I try to improve the quality of my images of Jupiter.
But the C14 was poorly constructed. Once completely disassembled, I found that the primary mirror was displaced from its axis and tilted several millimeters, so it was impossible to collimate, and always showed a severe astigmatism. Furthermore, the grease had liquefied, and was converted into oil, dripping over the mirror.
I have spent my time devoted to astronomy to reconstruct the optical tube, sticks it with black velvet, building a colimable barrel for the primary mirror, building a supplement to the position of the corrector and the secondary mirror and creating a system that allows me collimating primary correctly. It was hard work, but I think the results are worth the effort.
I added a secondary collimation screws. I do not have much experience with C14 but it is hard to understand that every good night the telescope needs a little touch up collimation.
I have a question for friends who also have a C14 and take pictures and of Jupiter: I am working with a x2 (F20) barlow, and I focus on a satellite extending the display image to x2. Is it normal for the disc of the satellite is not a crisp circle? I see a circle but is always surrounded by some light, as if the corrector plate had some moisture (but not, of course)
Well, now I need millions of experiments to find the right way to get all the information that has the raw image. I am discovering that the treatment process is one of the best kept secrets of the Universe .
Regarding focussing...probably best to use a star with a focussing such as Bahtinov mask, since the Galilean Moons are discs in a scope of this size. I used to do exactly the same to focus with my smaller scope and when I upgraded to the C11 I noticed they are no longer points of light but very small discs
Thanks for the tips. A question... the Bahtinov mask works when I use a x2 barlow? Hum! I´m writing it and I´m answering myself "of course, stupid!" I will do a mask. I have one from my 10" but I feel is nor usable. And It need a hole for the secondary support. OK. Next work!
About treatments... Somebody know somewhere with a thread for to talk about it? but in a friendly way
A question... the Bahtinov mask works when I use a x2 barlow? Hum! I´m writing it and I´m answering myself "of course, stupid!" I will do a mask. I have one from my 10" but I feel is nor usable. And It need a hole for the secondary support. OK.
Yeah the mask works at any focal length, or at least that's my understanding I didn't fancy an afternoon wielding scissors or a knife, so I bought mine but it worked at f/10 and f/25
After the C14 modification, I need a new mount. The EQ6 is really a great mount, but maybe I´m asking them too much mounting the C14 (and the filter wheel, finders, camera...). Because my pocket is not happy about to buy a EQ8, I have modified a DS16 Meade EQ. Basically I have mount the AR wheel and worm in the Dec. axis, and I have build a new 480 tooth wheel for the AR axis. The AR run really well, but the Dec. will need a modifications. But at least I´m sure that I not will find the C14 in the ground a night when I open the dome.
Now, I need a good seeing, but i don´t know how I can to do it And I ´m starting to process the images with Astra decons. And I have not idea ... but this is another war, I will ask in the adequate area.
That's really cool Pelu. So you've decoupled the baffle tube from the mirror cell and mounted the whole system on a tilt plate? How did you mount the mirror on the baffle tube? Gel?
Hello Marc. No, the baffle must be in their place. If not, the light of the sky will enter directly to the camera or eyepiece. If you see the new barrel images, you see the original aluminium trefoil between the two new trefoils. The first one is fixed to the original (in this way, the telescope can be focused with their knob) and the second one is floating with spring and screws as a normar Newton barrel; and the rear cover now have three holes to access to the colimation screws. The central hole in the second trafoil have just a slight play with the baffle, and a small collar fit the mirror centered. The mirror is glued to this second trefoil with silicone. Is difficult to write for explain it... will be easier with a pen in my hand (and a bier in the table )
Hello Marc. No, the baffle must be in their place. If not, the light of the sky will enter directly to the camera or eyepiece. If you see the new barrel images, you see the original aluminium trefoil between the two new trefoils. The first one is fixed to the original (in this way, the telescope can be focused with their knob) and the second one is floating with spring and screws as a normar Newton barrel; and the rear cover now have three holes to access to the colimation screws. The central hole in the second trafoil have just a slight play with the baffle, and a small collar fit the mirror centered. The mirror is glued to this second trefoil with silicone. Is difficult to write for explain it... will be easier with a pen in my hand (and a bier in the table )
I see. I did something similar on my C11 but I'm thinking, in future, to have the whole baffle tube moving instead of the mirror support.
PS: Looking at the original mirror mounting, it looks like they've used some kind of white cement. You can see the cork sticks embedded in it. My C11 had three paddle pop sticks. That's for support and initial spacing until the cement cures. I'm really interested in that compound they use. In my experience silicon is the worst thing you can put on a mirror mounting.
Very good work, Marc. The mechanical concept is the same that mine. I can´t see the need of moving the baffle. On the contrary, I used the baffle as reference for the colimation of the primary, because it seem well mechanised an centered in the tube.
Very interesting the way to collimate. I have create my own system, but I need to remove the lame for to do it; i will thing about your way a bit more
For to fix the mirror Celestron used a some kind of two component silicone, like is used for moulding. These silicone fill all spaces but not adhered parts. The silicone I used yes, is the same we used for the windows glass. And yes, is a good way to fix telescope mirrors, but requires some care: because the silicone have some contraction and produce a stress and deformation of the mirror, I put three coins between the three dots of silicone and when the silicone is cured I remove the coins and the mirror remain "floating", and the dots of silicone compensate its contraccions.
The white compound inside your primary bore looks like plaster? I wonder if casting plaster in the bore would set the glass without straining it, opposed to silicon. What do you reckon?
. A friend gave me a C14 optical tube, for I try to improve the quality of my images of Jupiter.
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I have modified a DS16 Meade EQ. Basically I have mount the AR wheel and worm in the Dec. axis, and I have build a new 480 tooth wheel for the AR axis. The AR run really well, but the Dec. will need a modifications. But at least I´m sure that I not will find the C14 in the ground a night when I open the dome.
