Axel,
from Astronomical tables of the Sun, Moon and Planets, Jean Meeus, second
edition, page 151: Semptember equinox in 2011 is on day 23rd at 9:05:44
(Dinamical Time). To convert to Universal Time one must subtract the value of
DeltaT.
Orologi Solari considers a value of DeltaT = 67.5 so
Alex
You say in your note But in mathematics uuuf, - but this is not
mathematics, it's astronomy! Nothing in the heavens moves with absolute
uniformity…..
If you want the very best astronomical calculations, then you must use the best
technology and that is provided free by NASA-JPL.
Gian et al:
I need to take back my last statement: it turns out that VSOP is accurate to
about 10**(-6) degrees.
Brad
On Tue, Sep 27, 2011 at 5:36 AM, Brad Lufkin bradley.luf...@gmail.comwrote:
Gian:
it's likely that the difference between your result and the result in Meuus
is due to (a) the
On trying to access the Courtyard Sundials website, I was saddened
to see a message that Richard White has died - and that the business
is therefore no longer trading. Was it previously reported, on this
Mailing List, or did I miss and/or forget notification of his death?
I am sure that Richard
Just for clarity:
http://aa.usno.navy.mil/data/docs/EarthSeasons.php shows the following
UT values:
20112011
Perihelion Jan 3 19Equinoxes Mar 20 23 21Sept 23 09 05
AphelionJuly 4 15Solstices June 21 17 16Dec 22 05 30
ie: 9:05 UT
from
Brad,
sun parameters are computed by OS using the VSOP87 theory as for Meeus results.
Aberration and nutation are taken into account (or they should be, this is one
of the points I have to check).
I did not interpolate but just manually changed the simulation time in order to
get 180.0
Gian:
I calculated the longitude using VSOP87D and all the corrections mentioned
in Meuus's Astro Algorithms and, if it makes you feel any better, my result
agrees with yours (i.e., the Sun's longitude is closest to 180 degrees at
9:05:41 DT).
Brad
On Tue, Sep 27, 2011 at 2:22 PM,
