metasofa sun-moon-earth clock

about the sun-moon-earth clock

the metasofa sun-moon-earth clock is an earth-centric planetary orrery for locating the sun (yellow disc) and moon (blue disc) in the sky at any particular time, and for estimating tidal forces influencing oceans and emotions on earth.

on the clock-face, the distance of the sun & moon discs from the center of the clock (earth) are proportional to their gravitational tidal forces upon the earth.  closer to the center is stronger.

the floating gray disc shows combined tidal force of sun and moon, which depends on lunar phase.  approx relative numbers - sun 5, moon 11, maximum 16 at new moon (11+5), minimum 6 at full moon (11-5).

the direction of the center of our galaxy is indicated by a small white "galaxy" disc within the outer blue "stars" ring  (influences unknown :)

from the northern hemisphere of earth looking toward the southern sky, left on the clock-face is east, right is west, up is above the horizon, and down is hidden below the earth.  as the earth rotates toward the east, the sun and moon and stars appear to rise in the east and set in the west.  (for southern latitudes, see "how to use" below)

when the sun and moon are aligned, it's a new moon.  when the sun and your winter solstice align, it's a new year.  when sun, moon, and winter solstice all align (every 19 years), it's a new "saros".  on the clock-face in the outer blue ring, metasofa saros phase is indicated by a small light square relative to the galaxy disc.  (the galactic center is currently near the december solstice)

a "metasofa saros" is exactly 235 (tropical) lunar months, just about 2 hours longer than exactly 19 (tropical) years, aka the metonic cycle.  maybe not as useful for predicting eclipses, but very relevant for weather.

how to use

the standard 12-hour clock (green minute-hand & purple hour-hand) follows your setting in the timezone menu, while the sun-moon-stars orrery follows your exact longitude in the long text-box.  enter +degrees for east of greenwich, or –degrees for west, or blank to calculate longitude from your selected timezone.

the clock can be set to automatically track the current time.  just set the refresh menu and click time now.  (on this planetary time-scale there is no second-hand, so you can relax! :)

you can also explore specific moments in the past or future with the date & time menus.  click this date or any +/– button to go there.  (this clock is limited to dates between 1902 and 2037)

southern latitudes

"clockwise" is evidently a northern-hemispheric viewpoint.  from the north looking south, left on the clock is east, right is west.  southern-hemispherians may mirror-flip the sun-moon-stars orrery with the lat menu.  choosing latitude "south" shows east on the right, and west on the left, which might make more sense when looking north from the south.

clock only

to open the clock in it's own window, click the clock-only link, or you can bookmark the link and open it later.  note that a clock made for a specific date-time (or shown with IMG) will not auto-refresh.  to make a clock that tracks the current time, set the refresh menu and click time now.

the clock is an SVG image which can be included within a webpage via IMG, OBJECT, IFRAME etc.  permission granted for non-commercial use only, please credit with this link - time.metasofa.org

accuracy

disclaimer about accuracy - compared with state-of-the-art interplanetary navigation instruments, this is indeed a "mickey-mouse watch" intended for quick estimates of the sun-moon-earth situation.  it assumes flat circular orbits, constant rotation etc, so please don't blame us if you can't parallel-park your shuttle pod with it :)

accurate times for solstices, equinoxes, and lunar phases can be found on the metasofa lunar calendar - metasofa.org/time/lunar

up to clock