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Astrology software to calculate geocentric and heliocentric aspects,
world transits, personal transits and synastry

January 20, 2020, 12:00 GMT
Julian date: 2,458,869.00
Ecliptic longitudes
Planet Geocentric Heliocentric
Sun299°53'29Cap53 
Mercury306°19'6Aqu19322°13'22Aqu13
Venus338°8'8Pis835°33'5Tau33
Earth 119°53'29Can53
Mars251°34'11Sag34223°37'13Sco37
Jupiter281°7'11Cap7277°40'7Cap40
Saturn293°42'23Cap42293°6'23Cap6
Uranus32°41'2Tau4135°32'5Tau32
Neptune346°44'16Pis44348°7'18Pis7
Pluto293°2'23Cap2292°51'22Cap51
Moon247°26'7Sag26 

Visit our Software Shop to see software available and prices.

VirusTotal says www.planetary-aspects.com is a totally clean siteThere are several different types of astrology program. One difference is whether the program concerns geocentric astrology, heliocentric astrology, or both. In geocentric astrology the zodiac is viewed with the Earth at the center, whereas in heliocentric astrology the Sun is at the center. Most astrological software is geocentric. Among the four astrology programs shown below, two are purely geocentric, one is purely heliocentric, and one supports both types of astrology

Astrology software used by Vedic (Indian) astrologers uses a sidereal zodiac, whereas Western astrologers tend to use a tropical zodiac. The difference lies in the definition of 0° Aries, that is, the direction in the heavens from which the 360 degrees of the (or a) zodiac is reckoned. In Vedic astrology this is defined with reference to the fixed stars, but in Western astrology it is defined with reference to the vernal equinox.


VirusTotal says www.planetary-aspects.com is a totally clean site The four programs below run under all versions of Windows from Windows XP to Windows 10. (They cannot be run on Macintosh computers except by use of a Windows emulator.) The downloadable trial versions can be made fully-functional by means of an activation key. The key can be sent immediately upon purchase of a user license (or can be obtained soon after). Updates to new versions are free. For more details and to purchase a program either click on an image below or visit our Software Shop.

What's a planetary transit?

Planetary aspects occur when two planets possess a particular angular relationship with each other (e.g. conjunction, opposition, trine, square, etc.) with respect to a central point. This point is either the Earth (in geocentric astrology) or the Sun (in heliocentric astrology). A planetary transit is the period during which two planets remain continuously in a particular aspect with each other.

The programs described here either display planetary aspects and transits or calculate the exact dates and times at which transits occur (begin and end) between selected planets. Click on any of the program titles or screenshots for more information about a particular program (and the user manual). Or to get short descriptions of these programs visit our software shop.

Astrology without houses

The reason that none of these four programs involve an ascendant, or astrological houses, is that the ascendant (and thus any house system) depends on a geographical position (usually a birthplace). But aspects between planets, and thus planetary transits, depend only on the motion of the planets along the ecliptic as viewed from the Earth (or the Sun). Thus a planetary transit does not require, or imply, an ascendant (and thus no house system). Aspects and transits have their own astrological meaning. (Yes, astrology without houses is possible.) Signs (derived from the equal division of the ecliptic) are as usual, for example, Neptune is in Pisces from April 4, 2011, through March 30, 2025; and see this Su‑Me‑Sa‑Pl 4‑stellium in Capricorn on January 12, 2020). For a heliocentric example see this double kite.

There are 7 house systems commonly used by astrologers, and over 20 are possible. They give different results when interpreting a horoscope (and the Koch and Placidus systems don't even work for locations above the polar circle). Which gives the "correct" interpretation? You pays yer money and takes yer pick. Or should we just conclude that houses are bogus, and only aspects and transits are worth our attention?


Combo offer: If you can pay via PayPal then you can obtain a discount of up to 40% by purchasing 2, 3 or 4 programs at once. For this go to our Software Shop.

The developer of these computational astrology programs
is currently available for custom software development (and mentoring)
at an affordable rate. If interested please leave a message here.