ELT telescope is really huge and exceptional. I tried to model the mirror and then simulate the rays. I don’t think I have the last coefficient for the optics has some of the last coefficients are not the same on the ESO website, but as I need all parameters (see image at the end) I can’t use them. The ray converge to a 10 mm radius, I don’t know if it is correct or if there is a slight error somewhere.

Three mirror are aspheric so there are defined by coefficients that link the Z to the radius Z=\frac{r²/R}{1+\sqrt{1-(K+1)r²/R²}}+A r^4+B r^6
So I calculate Z for various radius, make an interpolation curve then I revolve this curve.
I just made a little C# to calculate the perfect ray reflection.

Why were so many intermediate mirrors used? It would seem that every time you introduce a new reflecting surface you have a chance of multiplying errors.

Hello
I am working for nobody I just questioned myself if a 3d model of the ELT was worth to be published on Turbosquid (I have already some other models on this platform). Before doing a model I search for information, drawings … and because I like to make things the most accurate I search for the optics. I found that interesting and I wanted to place the optics with the good distance and test if my model was realistic.
I am not very pleased with my Grasshopper script, not enough generic and simple. I will be happy to have a sort of description of the optics and an automatic Grasshopper to make it. But if you want to try I can publish it.

I am not an optic specialist but this telescope have many adaptive optics to cope with air turbulence, deformations of mirror (wind, heat …) and also to make the focus. There were lot of studies with differents optics configuration, size … and they choose this configuration.

This kind of telescope is named " Nasmyth Telescope’"

Hi Lauerent,
Awesome work. I can’t tell for sure but your rays should focus to a point if not you might have errors in one of your mirrors surfaces. Also can’t tell from your pic but the focal distance of the observer might be shorter closer to the scope sorry it’s hard to tell. When I have the time I want to build a Tri sheifspiegler. Thanks for posting can’t wait to see images from that scope it’s suppose to out perform the Hubble.
RM