Eclipses and Saros Cycles in Astronomy and Astrology
I’ve been doing some research on eclipses and realized it would be useful to have an “Eclipse 101” type of reference post. There’s a lot of basic astronomical information about eclipses that’s really useful to know when you’re studying eclipses from an astrological point of view.
Basic Eclipse Information
Solar eclipses occur at the New Moon (Sun-Moon conjunction).
- This is when the Moon passes in front of the Sun, darkening its light.
Lunar eclipses occur at the Full Moon (Sun-Moon opposition).
- This is when the Moon passes through the Earth’s shadow, giving it a reddish hue.
Eclipses occur in pairs, twice a year.
- There is always one solar eclipse followed by one lunar eclipse, or vice-versa.
- Occasionally there can be a third eclipse, which will be the same type as the first one in the set (solar-lunar-solar or lunar-solar-lunar).
Eclipses always occur within about 17 degrees of one of the Lunar Nodes.
- The closer the Sun and Moon are to the Nodes, the more total the eclipse will be.
Eclipses are only visible from certain locations on earth.
- Those outside the path of totality will see a partial eclipse.
- Those too far outside the path of an eclipse will not be able to see it at all.
Types of Eclipses
Eclipses are classified according to how complete they are, which depends on the alignment of the Sun, Moon and Earth.
Total Solar Eclipse
- The Moon completely blocks the Sun, creating a path of totality on the Earth’s surface.
- Those inside the path of totality will experience daytime darkness and be able to observe the Sun’s corona.
- Those outside the path of totality will experience a partial eclipse.
Partial Solar Eclipse
- The Moon covers only part of the Sun.
Annular Solar Eclipse
- The Moon is centred in front of the Sun but doesn’t completely cover the Sun’s disk.
- This occurs when the Moon is near apogee (its farthest distance from the Earth) and creates a “ring of fire.”
Hybrid Solar Eclipse
- This is a combination of all three types of solar eclipses, depending on the observer’s location.
- Hybrid eclipses begin as an annular eclipse and transition to a total eclipse, then finish as an annular.
- Those outside the path will see a partial eclipse.
- These are rare and only happen once per decade.
Total Lunar Eclipse
- The Full Moon is completely blocked from the Sun’s rays by the Earth’s shadow (penumbra).
- This is also called a Blood Moon because the Moon appears reddish-orange, because of dust particles in the Earth’s atmosphere which bend sunlight and allow different wavelengths of light to reach the surface of the Moon.
Partial Lunar Eclipse
- The Earth moves between the Sun and the Moon, but the objects are not precisely aligned so the Moon only appears slightly reddish and not all of its surface appears that colour.
Penumbral Lunar Eclipse
- The Moon moves through the faint outer part of the Earth’s shadow (penumbra).
- This is a very faint eclipse that often looks just like a regular Full Moon.
Each eclipse belongs to a particular Saros cycle, also called Saros series, which is a sequence of eclipses that occur at intervals of a Saros.
- A Saros is a period of 223 synodic months or almost 19 years (technically, 18 years and 9 to 11 days, depending on the number of leap years in that period), after which the Sun, Moon and Earth return to approximately the same position and thus cause a nearly identical eclipse to occur.
- Thus, a Saros cycle/series is a sequence of similar eclipses that occurs every 19 years.
Each Saros cycle is identified by a number.
- You can use the particular Saros cycle number to look up all the eclipses in that cycle.
A lunar Saros cycle consists of about 50 lunar eclipses over about 870 years.
A solar Saros cycle consists of about 70 solar eclipses over about 1200 years.
At any one time, there are about 42 Saros cycles running at once, resulting in just over two eclipses a year.
Each Saros cycle begins with a tiny eclipse at the north or south pole and then each successive eclipse shifts slightly north or south towards the opposite pole, and is about 120 degrees west of the previous eclipse in the series.
- Therefore, you can tell the approximate age of an eclipse based on where it occurs:
- Younger and older Saros cycles consist of small partial eclipses close to one of the poles.
- Middle-aged eclipses are closer to totality and occur across the middle of the Earth.
Because eclipses always occur in pairs (one lunar and one solar), each Saros cycle has a “partner” of the opposite type.
- For example, the next eclipse that occurs on April 30, 2022 is a partial solar eclipse belonging to Saros cycle #119.
- The partner of solar Saros #119 is lunar Saros #112.
Eclipses in Astrology
Vedic astrologers conceive of the Lunar Nodes as a great dragon. The North (Ascending) Node is Rahu, the head of the dragon. The South (Descending) Node is Ketu, the tail of the dragon.
This imagery, of a great dragon wrapping itself around the earth, matches perfectly to the way that each Saros cycle moves slowly up or down the Earth from pole to pole. They begin as a tight curl at the pole, lengthening into sinuous waves around the middle of the Earth, and then tightening up into a little curl again at the opposite pole.
In both Vedic and traditional astrology, eclipses and the Lunar Nodes are regarded as malefic, negative influences. This is particularly true when eclipses occur close to the degrees of an individual’s natal chart angles or natal planets.
Many modern astrologers regard eclipses – and by extension, the Lunar Nodes – in relation to themes of reincarnation, karma and past lives. Some modern astrologers do not regard eclipses as malefic influences per se, but most acknowledge them as delineating periods of profound transformation and major life transitions – again, usually when they hit key aspects in the individual’s chart.
Saros Cycles in Astrology
There are many ways of using Saros cycles in astrology. One of the most common is to look at the Saros cycle of your prenatal eclipse (usually the prenatal solar eclipse) for some insight into the life path or soul journey of your current incarnation.
Because each Saros cycle repeats every 19 years, the recurrence of your prenatal solar eclipse occurs at ages 19, 36, 55, 74 and 93. This is commonly referred to as an “eclipse return.”
However, we don’t need to limit ourselves to just looking at the prenatal solar eclipse! You can look up the Saros cycle for any and every eclipse that occurs, and know that this series will repeat again every 19 years. This is particularly useful when an eclipse hits a key degree in your chart – you can prepare yourself for what may occur the next time it comes around.
You could also do this for key moments in history, tracing backwards and forwards in time what occurred in history during each Saros cycle.
Note: I’d like to thank Julija Simas for introducing me to using Saros cycles in astrology, at an OPA workshop in 2021.
Another way that I like to use eclipses is to look at where the path of totality will be on Earth, and where the point of maximum visibility/totality will be. Then, I compare this to what’s going on geopolitically in those regions. I also look at where the eclipses fall in the natal charts of the impacted nations. This is most useful when looking at a series of eclipses and a broader section of history/current events, versus just a single point in time.
I check the Saros cycles too, as those can be interesting when you go back in history and see what happened during previous instances of that eclipse cycle.
I also tend to consider the eclipses in terms of the series that occurs within the same zodiac sign axis, which is determined by which signs the Nodes currently occupy. For example, right now the Nodes are in Taurus and Scorpio, and I’ve been researching 2022’s eclipses which occur across that axis.
Keep in mind that there’s always some wiggle room on either side and there will be eclipses outside of the Nodes’ current signs when the Nodes are close to the beginning or the end of the sign. These transition periods are interesting in their own right. There are never any hard starts and stops in astrology; everything is always part of a bigger cycle.
Eclipse and Saros Cycle Resources
Hermit Eclipse website: great resource for information on eclipses and Saros cycles
GreatAmericanEclipse.com: detailed info and excellent maps from an American point of view