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<Thierry> wrote in message news:4505e10c$1@xxxxxxxxxxxxx
> Hello,
>
> A question about historical truth.
> It is said that Galileo discovered the phases of Venus phases in 1610. OK.
> It is also said that he invented his scope only in 1610
> Two dates to be confirmed, and if possible in the month close...
Looks like the dates may be in error
Wikipedia
"Based only on sketchy descriptions of the telescope, invented in the
Netherlands in 1608, Galileo made one with about 8x magnification, and then
made improved models up to about 20x. On August 25, 1609, he demonstrated
his first telescope to Venetian lawmakers."
http://en.wikipedia.org/wiki/Galileo#Astronomy
> If I simulate the sky at that time, of Firenze, arcetri, we discover that
> in Jan-April 1610 Venus was in the East, 10° over the horizon with 80%+
> illuminated, thus very small, and at the end in the rays of sun. hard to
> imagine that he observed it at that time. It nevertheless could have did
> it.
> On the other hand, at the autumn 1609 venus shows a fine crescent, and was
> higher in the sky of the morning
Good work, and could well suggest that he observed Venus in Autumn 1609
rather than early in 1610.
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