----- Original Message ----- From: Krzysztof Kotynia <[EMAIL PROTECTED]> To: Rudolf Hooijenga <[EMAIL PROTECTED]> Sent: Saturday, September 25, 1999 11:34 AM Subject: Re: Equation of Time Graph wrong way up Down Under ?
> > While that in itself is commendable, I really like more the presentation > > which has the EOT negative in February and positive in November, because the > > dial is really slow in February and really fast in November, which is > > represented by the wavy EOT line, whereas Mean Time has always equal-length > > seconds, and days, and is best represented by the straight horizontal line > > of zero. > > > In 1930 International Astronomical Union agreed for > eq. of time to take role of an instrumental correction > to receive true (or apparent) time from the mean time > shown by clocks, > similarly to e.g. corrections added > to sextant measurements to receive true altitude of the > sun from instrumental measurements. > > So the equation of time should be taken with a minus sign > as a correction for sundial to receive a mean time. > > > > > Best regards > Krzysztof Kotynia >
