Planetary Phenomena
Tables of Planetary Phenomena 3000 BC to 3000 AD

All these predictions (with the sole exception of solar and lunar eclipses) are derived from the JPL DE406 ephemeris, a numerical integration of the equations of motion of the planets spanning the period 3000 BC to 3000 AD. This data is available on the JPL Planetary and Lunar Ephemerides CD-ROM from Willman-Bell, which also includes the (older) DE200 and (shorter-span) DE405 integrations. The Fortran (ugh!) programs are not of much use, but you can learn how to evaluate Chebyshev polynomials efficiently from the explanations of the old "Almanac for Computers" (USNO), and the rigurous algorithm for "planetary reduction" appears in both "The Astronomical Almanac" (USNO and Her Majesty's Nautical Almanac Office) and the "Explanatory Supplement to the Astronomical Almanac" (P Kenneth Seidelmann, Ed., University Science Books, 1992).

The positions DE406 gives for Neptune and Pluto, and even Uranus, deviate significantly from those of prior integrations (and of the VSOP87 theory, based on DE200) when you go many centuries into the past (essentially, before Galileo's sighting of Neptune it's anything goes, I guess). Bill Gray's comment on the subject (I was using his GUIDE 7.0 program, which uses VSOP87, to view the predicted events): "VSOP87 matches wonderfully to the (older) DE205 and DE206 ephemerides. These, in turn, match fairly well to the (newer) DE405 and DE406 ephemerides... except that the newer ones use a different mass for Neptune, by about 1 part in 200, derived from the Voyager flyby. That adjustment results in a substantial change for positions of Neptune, and some change for Uranus."

The DE406 ephemeris is available on the CD only in what they call binary "Unix format", which is a binary file with two header records containing information about the timespan of the ephemeris and the constants used in the integration followed by blocks of IEEE 754 double-precision (64-bit) floating point numbers stored in most-significant-byte-first order. These were first converted to so-called "Intel format" (least-significant-byte-first) order.

These files can be significantly reduced in size with almost no real loss of accuracy (planetary positions are not known with the millisecond precision of the ephemeris listings) by chopping off about half the Chebyshev terms (the number of truncated coefficients is actually determined by specifying a maximum interpolation error for each planet within the given timespan: on the order 1 km for the Moon but 100 km for the outer planets, for example) and storing all coefficients as 32-bit IEEE 754 numbers. The result is that you can store an extremely accurate ephemeris of the Sun, Moon, and Planets at a little more than 1 megabyte per century, with the advantage that recovering the planetary positions from Chebyshev series is much faster than evaluating thousands of VSOP terms!

From 2001 AD to 2100 AD

Solar Eclipses in the 21st Century.

A simple list of all the solar eclipses in the 21st Century, indicating only the type and magnitude of each one. No information about regions of visibility is given.

Lunar Eclipses in the 21st Century.

A simple list of all the lunar eclipses in the 21st Century, indicating only the type and magnitude of each one. No informatino about regions of visibility is given.

Transits of Mercury and Venus in the 21st Century.

The two transits of Venus and fourteen of Mercury that happen in the new century.

Occultation of Planets and 1st-Magnitude Stars by the Moon in the 21st Century.

A long list with all the occultations by the Moon of Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Aldebaran, Regulus, Spica, and Antares. No info about regions of visibility though...

Mutual Planetary Conjunctions and Occultations in the 21st Century.

All instances of two planets approaching within 5° of each other, including five planetary occultations.

Occultations of Stars by Planets in the 21st Century.

Took the 626 stars magnitude 6.0 or brighter from the old Zodiacal Catalog (thanks to Paul Schlyter, there) and tested them against all eight planets. Computed star positions include proper motion, but neither parallax nor radial velocity.

From 3000 BC to 3000 AD

In these pages, negative years are "BC" years. That is, 1 AD appears as +1 and the previous year, 1 BC, appears as -1 (there is no "year zero"). Some people prefer to refer to the year 1 BC as 0, saying it is "the calendar year 1 BC, and the astronomical year 0". If you are comparing negative years, be aware of this difference: the "astronomical year" number is always one greater than the "calendar year" number for BC dates, so 100 BC appears here as -100, but may appear in other places as -99.

Occultations of Stars by Planets from 3000 BC to 3000 AD.

Tested all eight planets against each other, and recorded all instances where their minimum distance is smaller than the sum of their apparent equatorial semidiameters plus the parallax of the nearest minus the parallax of the farthest. This assumes all planets, and the Earth, are perfectly spherical. As we know, Jupiter and Saturn are far from spherical, so there might be a non-event or two hidden in that long list: always double check!

Close Planetary Conjunctions from 3000 BC to 3000 AD.

All planetary pairings where the minimum distance is smaller than 20' are contained in the conj20.zip file linked from the page. The on-page listing includes all conjunctions to within 15' for the period 1800 to 2100 AD.

Occultation of 1st-Magnitude Stars by Planets from 3000 BC to 3000 AD.

How many times have the planets occulted the first-magnitude stars (Aldebaran, Regulus, Spica, and Antares) in these 6000 years? I also thought that was an interesting question. The results may surprise you!

Transits of Mercury and Venus from 3000 BC to 3000 AD.

A brief discussion of the 243-year cycle of Venus transits, the 46-year cycle of Mercury transits, and the four and six (respectively) series currently active, followed by a list of all these transits.

Solar Transits of One Planet Seen from Another from 3000 BC to 3000 AD.

Why not? Did you know that the angular diameter of Jupiter during transit as seen from Saturn is about a quarter of the angular diameter of the Sun? Statistics and a listing (in a .zip file) of all the transits visible from the surfaces of all the planets. Again, all planets are considered spherical, their radius being their equatorial radius as given in the "Physical Ephemerides..." chapter in the Explanatory Supplement to the Astronomical Almanac (that goes both for the transiting planet and for the planet you are viewing from, where the "home planet's" radius is used to calculate the transiting planet's parallax).

Closest Approaches of Venus to Earth from 3000 BC to 3000 AD.

How close does the closest planet come to Earth? Here you will find a list of the closest inferior conjunctions of Venus.

Closest Approaches of Mars to Earth from 3000 BC to 3000 AD.

And how close can the Red Planet come to Earth? A list of the closest perihelial oppositions of Mars.

Lunar Perigees and Apogees from 3000 BC to 3000 AD.

What is the closest and the farthest the Moon has been to the Earth in these 6000 years? A list of extreme perigean and apogean distances, plus one .zip file with all 79,535 perigees, and another with all 79,535 apogees, sorted by distance. Note that the circumstances for a close lunar perigee, as well as the lunar perigee itself, are the same circumstances that produce the highest possible spring tides. So when did the highest tide happen?

Close Groupings of Three, Four, and Five Planets from 3000 BC to 3000 AD.

 What are the tightest grouping of 3, 4, or all 5 of the naked-eye planets? This page lists all 5-planet groupings within 15 degrees from 3000 BC to 3000 AD, all 5-planet groupings within 30 degrees from 1500 AD to 2500 AD, all 4-planet groupings within 4 degrees from 3000 BC to 3000 AD, all 4-planet groupings within 8 degrees from 1500 AD to 2500 AD, and all 3-planet groupings within 1 degree from 3000 BC to 3000 AD (in order of tightness) and from 1500 AD to 2500 AD (in chronological order).

From 2001 AD to 2100 AD

Solar Eclipses

Lunar Eclipses

Transits of Mercury and Venus

Occultation of Planets and 1st-Magnitude Stars by the Moon

Mutual Planetary Conjunctions and Occultations

Occultations of Stars by Planets

From 3000 BC to 3000 AD

Occultations of Stars by Planets

Close Planetary Conjunctions

Occultation of 1st-Magnitude Stars by Planets

Transits of Mercury and Venus

Solar Transits of One Planet Seen from Another

Closest Approaches of Venus to Earth

Closest Approaches of Mars to Earth

Lunar Perigees and Apogees

Close Groupings of Three, Four, and Five Planets

Project Pluto's Guide Add-On Files

  • ETB Files for Planetary Phenomena.
  • 60,000+ Places GEONAMES.DAT File