Hopefully the COVID-19 has not impeeded you cool project and you are able to complete your structure. Really interesting project.
My 2 cents, there is a very painful world of difficulty between someone making a few 500mm mirrors at F4-5 and figuring a perfect 800mm at F3.
The level of difficulty is really not linear from one size to another, especially at faster F-Ratios.
What places have you quoted for the mirror out of curiosity?
Hi Hugo thanks for checking out - as a matter of fact the assembly is taking place in Cremona which was the epicenter in Italy. All the guys supporting the project are doing well although the activity is halted as the lockdown is going to be partially lifted starting next week.
To make the most out of this situation we are having call confs to decide the strategy over the making of the mirror - a meniscus is one of the option. Mel's - and other people's - work is inspirational and somehow the complexity is recognized. We have slumped mirrors and have some experience in mirror making but as you are pointing out, a bigger faster mirror is a double step-up.
But hey, don't we like challanges?
I requested for quotation soem time ago...I think I recall Hubble Optics, Fullum and a couple of other chaps in the US.