- This topic has 12 replies, 3 voices, and was last updated 8 years, 2 months ago by Massimo Marconi.
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1 March 2016 at 22:55 #7512
Even if I have not yet managed to start working the secondary , I fortunately found the time to complete the telescope project that will house the two Ritchey-Chrétien telescope mirrors, at least the design of the optical tube is complete, while the frame is still under development.
Based on previous experience with the self-construction of my ( ex) Dobson 300 F3.8 , He was born this new project that keeps intact many of the old features and also the Dobson “philosophy” constructive:
The optical tube fact, It is designed to solve some personal problems, namely, my total inability to work with machine tools , so all ( except one “piece” to work on the lathe ) It will consist of aluminum parts cut by laser / Waterjet (most likely by the same company that has pierced my primary ) and components of normal use found in good hardware.
I will not remain the task of assembling the components.then we start from the end ( design ), with some 3D render of the pipe:
1 March 2016 at 23:03 #7515For design lovers “classical” , here are two elaborate “standard” respectively for the cells of the primary and secondary:
https://www.grattavetro.it/wp-content/uploads/2016/03/T04-cella-primario-18pt-Layout1-1.pdf
https://www.grattavetro.it/wp-content/uploads/2016/03/T08-supporto-secondario-Layout2-1.pdf
1 March 2016 at 23:18 #7517Obviously I have not included in the project components that will be purchased
– focuser 2″ with step M90 attack 1
– diagonal 2″These are the “pieces” which will have to be cut from sheets / aluminum plates in thicknesses go, everything else is material to hardware…
https://www.grattavetro.it/wp-content/uploads/2016/03/T10-taglio-nesting-Layout1-1.pdf
2 March 2016 at 0:40 #7518The project seems to me nothing short of beautiful…
Great beautiful life exceeds rendering, congratulations…
I know so much that you will steal more than a few ideas for my next little project…eh eh eh…2 March 2016 at 3:21 #7519Thanks Mirco
a bit’ at a time we will reveal all the details, although some solutions may be “turn up one's nose”… anyhow, not having neither a mechanical workshop it the necessary experience to use, This is the most suitable to my constructive possibilities.Is’ clear that the type of optical configuration would require a much more level both in design and realization of, the tolerances are at stake “narrow” therefore do not be afraid, any improvement / suggestion / criticism is welcome !
Meanwhile, a particularly important project for us Grattavetro:
The primary lock can be easily disassembled by unscrewing the intubation 4 black knobs ( all black knobs are for clamping, blue ones are adjusting ). then unthreading the lens hood from the central sleeve can liberate the primary mirror from the cell. The rest intubation remains attached and tightened, the primary block is in fact independent.Important for all those who might be caught at any time, even in the dead of night, from “Test anxiety” or “Grattavetrite” generally
2 March 2016 at 21:24 #7526Bellisimo work.
Especially for the design feature that you indicated, the realization studied, few robust main pieces of the structure with the precision of the machine tool.I also like the design brainstorming, because I find it is always and definitely the way to have strength and also efficiency and simplicity, hence also weight control.
3 March 2016 at 18:54 #7528Thanks Giulio, Also I post the weights table, I have yet to finish entering all components.
In the meantime, let's see how he copes software ( Cinema 4D ) with the calculation of multiple reflections of parabolic surfaces.
The surfaces of the mesh of the mirrors were created “solo” parabolic with fire equivalent to that of the project, It does not seem appropriate to them hyperbolic…
To do this experiment I then took the telescope in the park , with my virtual assistant ( It is armed with a sword to protect the test from any hecklers… ) and I pointed the telescope at the vegetation about fifty meters .I positioned the assistant's eye squarely on the back-focus , I then inserted a tiny camera inside his pupil to realize what he saw…
then we go to verify the correct sizing of the hood and the resulting CPL, in the meantime, we observe how C4D gives us the image on the fire and verify CPL 30 mm moving later to the micro 15 mm left.I would say not bad, collimation is good ! also the image of the fire looks realistic, Whereas the objects are not infinite and therefore the resulting fire is slightly longer than planned.
I think that we, the sizing of the lens hood is properly.We do now to something more complicated software, positioning us with the virtual room in front of the first primary in a very off-axis position, and subsequently in front of the secondary.
I think it is quite realistic, However, the accuracy of the surface would be possible to further increase , and hence the realism of reflections, increasing the interpolation points of the parabola which, I am currently “solo” two hundred along a diameter. I do not know how about you, but according to me is C4D “promoted” honors !
3 March 2016 at 21:16 #7530Wow that forces…
What kind of a level of realism that can generate, and on curved surfaces, inter alia,…I'm amazed…
Not bad even your scientific-technical assistant…eh eh eh4 March 2016 at 3:04 #7531eh,eh… I knew that the assistant would have enjoyed “sympathy”. Here we talk about another kind of curved surfaces and I must say with a good “lambda”, but in these cases the “tests” They are made strictly live in a comfortable “laboratory”
4 March 2016 at 14:31 #7536I confess that I have to read it all… because it has very distracted me first the “back focus”…. Your assistant.
13 September 2016 at 19:04 #8324THE PROTOTYPE
I bet a Dobson RC had not yet seen ( Fortunately ), good! Also this gap was filled, Grattavetro now and we do not miss anything !
As already mentioned, I recycled much of my old Dobson, enough to build the prototype with plywood instead of aluminum, intubation test the project and test the mirrors while comfortably ( not so, no need for a hike in the base ) sitting. When the work will be expected to better construction, especially for the frame.
Do not mind the background, It is not a war zone, we are simply renovating…
Now I want to go on to post Dobsonians , I wonder if I am banned for life…
13 September 2016 at 22:34 #8326banned?? nooo! It's one beautiful instrument! Although it is not that “a wooden telescope”, as they say in Dobsonian (but much more well done of mine)… because it is always a noble RC, and even with fire Nasmyth
13 September 2016 at 23:07 #8330banned?? …but much more well done of mine)…
ah,ah by Giulio… better than your do not think so , We do not exaggerate… otherwise there bannano to both
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