Hi all
a couple of weeks ago I sent you news about a new app (on Sundial Atlas,
app 53) to get the equation of time of Mars.
I haven't heard of any spaceships leaving so I thought you might be
interested in the one for terrestrial resident as well :-)
There is no shortage of software to draw eot but this new app (app 29,
www.sundialatlas.net/atlas.php?ori=29) can draw the analemma starting
from the orbital parameters of the Earth:
- eccentricity of the orbit
- inclination of the ecliptic
- longitude of the perihelion
The app doesn't calculate these parameters but you can digit any values
to get the resulting analemma.
I found a web page of NASA (Goddard Institute for Space Studies) where
you can get the Earth's orbital parameters for the past or for the future:
https://data.giss.nasa.gov/modelE/ar5plots/srorbpar.html
I found interesting how the eot changes over the millennia and I
concluded that not all sundial time systems will survive.
Some sundials could become archaeological finds in a few centuries just
as we look at those of centuries, or millennia ago and the
understandable time systems in the future are: temporary, Babylonians,
Italians and local Sun time.
Not the analemma because eot changes over the millennia.
Not time-zone Sun time because the conventions change over the centuries.
Not mean time because leap seconds may be not updated over the decades.
Watching your wrist watch could become a goofy experience, one hopes to
be able to look at a sundial and know the local Sun time.
Also a Martian.
ciao Fabio
PS in the app 29 you can also enter parameters of other planets.
Remember that the longitude of the perihelion is a local reference, ie
it is measured from the vernal point of the planet's orbit.
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