On Apr 24, 7:57*am, Paul Hyett wrote:
On Thu, 23 Apr 2009 at 17:12:16, wrote in
uk.sci.weather :

Is there any *independent*
corroboration of a reduced solar output during 1645-1715? * In any
case a climatic deterioration had set in well before the Maunder
Minimum. * As far as I know there is no verification of the sun's
output being reduced during that period and futhermore it seems that
there is very little variation in solar output during a solar cycle or
from one cycle to the next, regardless of its intensity. *It would be
nice if someone could *confirm this, or deny it, come to that. *This
is like trying to get blood out of a stone and there seems to be
widespread ignorance and confusion on the issue.

I presume historic solar output is measured by some indirect means, as
with temperatures & ice-cores.

Unfortunately that doesn't tell you the solar output but only the
temperature on the earth.

However, it's possible sunspot levels *were* logged as early as the 17th
century - IIRC observing the sun was a major contribution to Galileo's blindness.

As to poor old Galileo it's interesting that he observed sunspots but
he cannot have measured the brightness, there being no means of doing
so at the time. In any case the figure required is that for solar
radiation above the atmosphere.


Tudor Hughes, Warlingham, Surrey.