Shortening a Newtonian telescope...?

[Chriske]

Didn’t want to hijack Astrofail's thread so started a new one.
His thread reminded me of a project I started ages ago.
In my case I wanted to test whether a larger obstruction in a telescope would degrade the image so badly as 'they' all say. Altough many parts were finished I had to abandon this project because at the time I started a new job, keeping me from finishing it.
And yes I did computer simulations using large obstructions in a Newt, but as always, I wanted to see with my own eyes if it would degrade so much that degradation would be seen visually.

Using that large flat, in the centre + that tertiary mirror(green), it's focuser is only at half the height of the focuser at far left.
To use that high placed(regular) focuser I need to tilt both(large flat + tertiary mirror) out of the optical path.
I mounted both focusing systems above one primary mirror. The idea behind it was to use the same primary mirror for both systems. To eliminate possible errors even more I made my own flats, and cut these three flat mirrors out of that one single sheet.

So... the only thing to do this all over again, is to look for all these parts. All of them are somewhere stored in a box gathering dust. If I only could remember what shelve....🙄
But I need to finish a few other large projects first right now...🤭

[Peter Drew]

I used to market a 8.5" F5 Newtonian with two secondaries and two focusers.  The secondaries were mounted on different length pre-collimated stalks that could be interchanged without losing the collimation.  The small secondary was on the short stalk, a 2x Barlow fitted to the focuser gave F10 and the larger secondary on the longer stalk operated at F5.  The telescope was optimised for widefield and high res lunar and planetary.     🙂 

[Chriske]

Woow... Got a picture...?

[Peter Drew]

Bit too long ago unfortunately.    😥