Re: VMs: RE: Re: Kircher's Moon

[Nick Pelling <incoming@xxxxxxxxxxxxxxxxx>]

Hi James,

> Now it is claimed that some culture knew, hundreds of years before the 
> invention of the telescope circa 1609, that Saturn had rings.  (This claim 
> is quoted in Velikovsky's _Worlds in Collision_, but be warned that 
> Velikovsky was a crackpot who makes Newbold look conservative and even 
> timid).  Some critic of Velikovsky suggested the following 
> hypothesis:  someone polished a shield or a brass bowl or something into a 
> good enough replica of a telescope mirror that s/he was able to make out 
> an image of Saturn good enough to show the rings.

I've had Robert Temple's book "Crystal Sun" suggested to me recently 
(though I thankfully managed to avoid actually having to read it): I'm told 
that the author reports having found some 250 rock crystal lenses (from 
Ancient Egypt), which might or might not be connected with some (ancient, 
lost, predicted) telescope and an (alleged) ability to resolve Jupiter's 
red spot. (I'm happy to let the astronomers here debate the magnification 
needed to resolve that vs Saturn's rings.) :-)

Now, while this ~may~ be evidence of ancient optical instruments, it's 
1000+ years away from my own point of interest - so I'll leave that for 
others to fight over gratuitously. :-)

David Hockney's recent work on mirrors and painting 1450-1600 might be a 
tad more relevant: certainly, by 1500, owning one of the (newly fashioned, 
and newly fashionable) curved mirrors was definitely the thing one did if 
one wanted to make a (fashion) statement to one's peers. But all paintings 
with these curved mirrors in the background appear to show them as quite 
modestly sized, convex & rotund (for want of a better word) - not really 
appropriate for astronomy etc.

Certainly Leonardo invested a great deal of time and effort trying to build 
machines to make very large curved mirrors circa 1500, with his German and 
French assistants - but the big question is why would he be so interested 
in making an ever larger curved mirror? The inference that he knew it would 
have interesting optical properties seems hard to refute... but AFAIK 
there's no definitive way to link this strand with astronomical practices. 
Anyway, it seems as though, like so many other things, da Vinci never 
succeeded in this enterprise anyway. :-(

I'm comfortable with the idea that by 1500, there was definitely what 
Thomas Homer-Dixon calls "an ingenuity gap" - people could feel a gap 
between what existed and what ought to be (cf Hume's fork) for curved 
optical instruments. But saying that gap had definitely been closed 
requires something rather more tangible as proof (either conceptually or 
practically) - neither of which I don't currently see. I'd love to have my 
view reversed on this, though! :-o

But Velikovsky''s "hundreds of years" before 1609? I can imagine stuff 
happening by (say) 1550, but significantly earlier doesn't really work for 
me, sorry. :-(

Cheers, .....Nick Pelling.....

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