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  • Ville Puoskari

Go fast, or go home! - Part I

Ever since I have built the first version of my travel telescope with a 3D printer - I have had a feeling I could make a larger aperture scope for my astronomical adventures. With larger aperture comes the inevitable problem of focal length - a 200mm f/5 telescope is almost a meter long! But what if you would go with a faster optical system? Well there is an idea! Que a long but fruitful conversation to India and the heart of this project is born at the hands of a master optician of Aperture telescopes. For a custom made mirror I wanted to go all in and boy did they not disappoint. The primary mirror is 200mm diameter f/3.3 light bucket with a measured Strehl ratio of 0.966!

With such a great mirror comes the need for a very good secondary mirror too. My first purchase of a 90mm diameter Hubble Optics secondary from Germany came in a million pieces due to poor packaging, although I got a full refund on that I have not been able to source another one yet in EU. Speaking of secondary mirrors - I have made some progress on the secondary mirror spider - the first iteration was 3D printed with an aluminum central piece for bolts. Then I had an idea that I could make the entire assembly if I just had a proper milling machine - or that was at least the excuse I gave myself (and the wife!) to buy a milling machine.

It remains to be seen which of these is a better solution, I'm keen to test them out for potential flexures once the OTA is completed. Stay tuned for part two!


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