might seem a bit far fetched but I've only been at this site a little while and have learned so much, no question unanswered yet - so I'll have a go with this:

Any advice/tips/starting points on how to go about grinding and polishing my own lens ?

... like I guess the old astronomers would have had to ...

some sort of lathe ? and then months of polishing ?

probably a maths degree ?

I dont want to make a super correct lens, and dont expect to be able to understand centuries of design in one go, but it would be nice to attempt to make one using the original old old (old) method/s