There was a question on the movements of the planets and I love math and geometry so couldn’t resist writing this high on numbers post.
Planets move around the Sun in at a constant speed and in one constant forward motion. (Heliocentric model). But when we see them from earth, they seem to go through various types of movements in the sky (Geocentric model). It is all about perspective, your position, the ‘frame of reference’ which we studied in physics in school is ultra-important. The path of the planets as seen from the Earth is called the geocentric epicycloid motion and it is a beautiful geometry, it is a spiral in space, ever evolving. Here are some images I picked out from the internet, but I suggest that you try to find some animated models so that you can appreciate the true beauty of the planet’s apparent motions.
This above is the annual motion of the Sun, Mercury, Venus and Mars as seen from the Earth. One circle is the path of one complete revolution of the planet around the Sun but as seen from the Earth.
This beautiful geometry above is the apparent movement of Venus as we see from the Earth. As Venus revolves around the Sun 5 times, its path makes this lovely 5 pointed star around the Sun from our perspective from Earth.
This is the geocentric epicycloid path of Jupiter, it is 12 Earth years long, Jupiter makes one revolution around the Sun in 12 Earth years. So his path makes this springy design as seen from the earth in 12 of our years. And Saturn’s path around the Sun as seen from the earth, he makes one revolution in about 30 Earth years, so his path is even more springier! The outermost circle is the 360degrees of the zodiac (Bhaa-chakra).
Life apparently and quite visibly goes in spirals!
When we look out from our Earth, we see that the Sun and the Moon move only in the forward direction. They move elliptically so their speeds vary a bit, but not very much, they can be considered to be moving at a constant speed. The 5 Tara graha, Mercury, Venus, Mars, Jupiter and Saturn move in these following eight types of movements (as listed in the Suryasiddhant written by Mayadanav). The two chhaya graha, Rahu and Ketu are a bit confusing, unless you have your astronomical concepts clear. Rahu and Ketu are mathematical points where the orbit of the Moon cuts the ecliptic. Generally people average out this calculation and use a ‘mean’ Node value. If you use Mean Nodes you will always have them moving retrograde at constant speed. And for horoscopes of souls at lower levels of evolution (post here), this much is enough. But if the chart is of a soul on a higher plane of evolution or you are analysing your own horoscope, you must calculate the ‘True’ node, ie the exact value of the nodes at the moment of your birth. These then true nodes can be in any of the eight motions as below.
The eight types of movements of the graha in the Geocentric model are,
- Vakra – Retrograde, when the planet in the motion reverse to the usual forward motion and apparently moves backward into the zodiac. e.g. Saturn goes retrograde on 11th May 2020.
- Anuvakra – When a retrograde planet goes back into the previous sign continuing in its retrograde motion. His speed has now slowed down a bit. Jupiter will do this when will reverse direction on 14th May 2020 and go back to Sagittarius on 30th June 2020.
- Vikala – no movement, the graha seems to be stationary. This can be for hours or upto 5 days days depending on the planet. e.g Saturn seems to stop /stambhit, for about 5 days before he changes his apparent direction of motion while Mercury is stationary for just a few hours. The True nodes can be stationary for days during a series of eclipses.
- Mandatara – forward motion but very slow
- Manda – slow forward motion but faster than than Manda
- Sama – the regular average speed forward motion
- Chara – is faster than the previous Sama
- Atichara – when a planet in forward motion is moving really fast and often enters the next sign moving really very fast, e.g. Jupiter had entered Sagittarius in Nov 2019 and he moved really fast and entered Capricorn in Mar 2020 covering one entire sign in 5 months!
If you have a sense for figures this is a useful diagram where you can see how the motion of the planet in the spiral goes apparently faster, slower, stationary, forward or retrograde etc. The numbers 1 to 8 are the above 8 motions of the planet in the curving spiral of the apparent motion. This spiral below would be the spiral section of the planet’s geocentric epicycloidal path which I have put above.
So now you know how the 8 types of motions are generated in the planet’s path as seen from the Earth.
The average time taken by the planets/ graha to cover 1 deg of the zodiac from the slowest to the fastest., ie Saturn = 29days 18hrs, Mean Nodes = 18days 21hrs, Jupiter = 12days, Mars = 46hrs, Sun = 1day, Venus = 15hrs, Mercury = 6hrs, Moon = 1.45hrs.
And the mean distance the graha cover daily in arc-degrees, arc-minutes and arc-seconds, from the slowest to the fastest, Saturn 2’, Mean nodes 1’15”, Jupiter 4’52”, Mars 37’, Sun 59’8”, Venus 59’8”, Mercury 59’8”, Moon 13deg10’36”
Now you have to find out what was the speed of the planets at the time you are interested in. Eg 12th Apr 2020, 9am Delhi, (you have to find this speed data online, this data is from Parashar Light).
So now if you compare it with the mean speeds which I have given above. Sun is moving a bit slower than average. Moon is moving a slightly faster than average. We would say that Sun and Moon are in ‘sama’ motion. Venus has slowed down, ‘manda’. Mars, Mercury, Saturn and Jupiter are moving significantly faster than their average speeds.
We need to check the speed of the graha to analyse its results, but very few astrologers will get into such analysis depths. The direction of its motion, retrograde/forward is also quite important to make sense of its effects in our life.