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PHP Astronomy and General Science Programs (v7.4.9 - v8.2.0) and Some Astronomical Tables

Computed by Jay Tanner - Many of these programs are available with complete PHP source code.

Kontakt:
Jay-T ât PHPScienceLabs • com

FOCUS: Astronomy, Physics, Mathematics, General Science, Math and Science Programming in PHP.
Each program attempts to open in its own tab. To exit a program, simply close its tab.

Many of the calculators are based on the NASA / JPL DE405 ephemeris model, used for several years as the basis of the Astronomical Almanac published by the US Naval Observatory. It is not entirely obsolete, as it gives reliable computations for several years past and into the future.

The same can be said for the VSOP87 theory. It is old, but not entirely obsolete and still has some practical applications and is still widely used today.

Some of the more recent calculators are based on the new JPL Horizons API and subject to its availability. These programs are first-generation experiments, since I'm still learning how to apply the API functions remotely. It can be vexing sometimes.

Obliquity of the Ecliptic and Latitudes of the Arctic and Antarctic Circles Calculator
Original Laskar Paper Used as the Basis of the Ecliptic Obliquity Calculator Above

Calendrical Date/Time Computations

Various Calculators To Handle Calendar Date and Time-Related Computations.

Sidereal Time Calculator For Any Date, Time and Longitude
JD Number Table Calculator For Any Given Month on the Old Julian or Modern Gregorian Calendar
JD Number Tables Calculator For Any Given Year on the Old Julian or Modern Gregorian Calendar
Computes the Difference Between Two Dates and Optional Times
Inverse JD Calculator - Given any JD Number or Julian Date, Computes Corresponding Calendar Date/Time
Parallel Julian and Gregorian Calendar Calculator to Compare Dates on Both Calendars
U.S.A. Holiday Calendar Calculator
General Calendar Calculator For Any Given Year

U.S.A. Daylight Saving Time Schedule Calculator
E.U. Summer Time Schedule Calculator

The VSOP87 Theory and Source Code Generator

This is the semi-analytical theory of planetary orbits for long-term computation of planetary heliocentric and barycentric coordinates which can be used for the computation of long-term planetary ephemerides.

About the VSOP87 Theory
VSOP87 - Equations Summary - Part 1 - Heliocentric Rectangular (X,Y,Z) Coordinates
VSOP87 - Equations Summary - Part 2 - Heliocentric Spherical (L,B,R) Coordinates

Multi-Language VSOP87 Source Code Generator - Generates VSOP87 Source Code In Five Programming Languages
VSOP87 - Check Values to Test If the Heliocentric VSOP87 Source Code Functions Are Returning the Correct Values

VSOP87 Venus Ephemeris Demo 1
VSOP87 Venus Ephemeris Demo 2
VSOP87 Venus Ephemeris Demo 3
VSOP87 Venus Ephemeris Demo 4
DOWNLOAD PHP Source Code For All VSOP87 Venus Ephemeris Demos 1 to 4 Above

VSOP87 Venus - Apparent Geocentric Ephemeris Interface Demo 1 - With PHP Source Code
VSOP87 Venus - Apparent Geocentric Ephemeris Interface Demo 2 - With PHP Source Code

VSOP87 - Daily Table of Geocentric Distances For the Planet Mercury (2000 BC to 6000 AD)
VSOP87 - Daily Table of Geocentric Distances For the Planet Venus (2000 BC to 6000 AD)
VSOP87 - Daily Table of Geocentric Solar Distances For the Planet Earth (2000 BC to 6000 AD)
VSOP87 - Daily Table of Geocentric Distances For the Planet Mars (2000 BC to 6000 AD)

NASA/JPL DE405 Ephemeris Calculators

NASA/JPL Horizons API-Based Computations With Optional PHP Source Code

Planetary and Lunar Perigee/Apogee and Earth Perihelion/Aphelion Computations Based On The NASA/JPL Horizons API

We generally think of the moon when we refer to apogee and perigee, but apogee and perigee points can also be applied to the planets as well. The point of closest approach to Earth is the perigee point and the farthest distance is the apogee point of the body in its orbit.

Here, the definition of the perigee and apogee points refers to the points where the radial velocity of the body, relative to Earth, equates to 0 (zero), after which, the radial distance trend (numerical sign of sequential difference) reverses. The points where the radial velocity equates to zero are at the minimum and maximum distance points from Earth.

When the radial velocity changes sign from positive to negative, the body has reached an apogee point and when the radial velocity changes sign from negative to positive, the body has reached a perigee point. By this definition, a body, such as the moon or the planet Mercury, can have more than two perigee/apogee events per calendar year.