Two Astrologies

zodiac clock

I noticed that Elvis, David Bowie, and Stephen Hawking all share January 8 as their birthdays. Had they lived to see 2020, Hawking would have been 78, Bowie 73, and Elvis would have been 85. That coincidence made me wonder if this simultaneity had any connection to their zodiac signs. But that would also depend on which of two astrologies you want to follow.

The horoscopes you commonly see use a system called tropical astrology which is the most popular system in the U.S. and Europe.

I learned this when I was back in college because of ​a college girlfriend who was deeply into astrology while I was into astronomy. She did not believe in the tropical astrological signs or the general horoscopes you find in newspapers and online. She told me about another system called sidereal astrology.

I have never been a believer in astrology and horoscopes, but this sidereal version seemed a bit more scientific, so it appealed to me. The popular tropical version doesn’t use the actual constellations in the sky on any day, including the positions of the stars at the time you were born. Tropical astrology is based on the seasons.

Sidereal and tropical are astrological terms used to describe two different definitions of a year.  A tropical year (also known as a solar year) is the time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth. For example, you could measure the time from the vernal equinox to the vernal equinox, or from the summer solstice to the next summer solstice.

On the other hand, if you measure the time it takes Earth to complete one full orbit around the Sun as measured with respect to the fixed stars, you have a sidereal year.

Ancient stargazers of 2000 years ago saw constellations that matched with the seasons. For them, the Sun was always entering Aries during the Spring Equinox. But the stars have slowly changed location relative to Earth’s seasons. By now, there is a difference of up to two zodiac signs between the popular horoscope system and the actual constellations up there now.

I found a lot of information about all this at  which is a site by Athen Chimenti who is a “sidereal astrologer.” (see video below)

Both systems divide the ecliptic into twelve “signs.” That divides the 360 degrees into 12 slices of 30 degrees.

That old girlfriend, Catherine, did my natal chart based on the stars at the time of my birth. (She wasn’t thrilled that I didn’t know the actual hour of my birth.)  I’m not surprised that technology can now do your chart much faster and easier than Catherine.

I don’t think Stephen Hawking would have had any belief in astrology, but if he did I think the sidereal approach would be his preference because it was more exact. I imagine that Elvis and Bowie (Starman) might have had some interest in their astrological horoscopes.

Using a calculator on, I generated this natal chart for my birth day. I don’t have that old one that Catherine did, and I don’t have her here to explain what it means. Back in college, she did explain it and a lot of things made sense. Of course, she knew me, so I always wondered if she was just telling me what she knew was true. I wish I remembered what else she said that didn’t make sense to me then. Maybe over the years, they came to be true too.

natal chart

Here are the sidereal signs which are based on the midpoint between constellations. If you are within three days of another sign you are supposed to be a blend of both.

Hey, Catherine – I don’t know where you are now, but it turns out I might be a Virgo instead of a Libra!

Aries (Apr 21 — May 12)
Taurus: (May 13 — Jun 19)
Gemini (Jun 20 — Jul 16)
Cancer (Jul 17 — Aug 6)
Leo (Aug 7 — Sep 14)
Virgo (Sep 15 — Nov 3)
Libra (Nov 4 — Nov 22)
Scorpio (Nov 23 — Dec 6)
Ophiuchus (Dec 7 — Dec 18)
Sagittarius (Dec 19 — Jan 19)
Capricorn (Jan 20 — Feb 13)
Aquarius (Feb 14 — Mar 9)
Pisces (Mar 10 — Apr 20)

Pleiades and Subaru

It’d a cold rainy night in Paradelle so there will be no Geminid meteors to see. But standing in my driveway, Christmas lights were reflecting very nicely from the stars on the logo on my Subaru.

Subaru logoSubaru means “unite” in Japanese, but there is also a celestial meaning to the logo. The six star cluster represents six stars in the Taurus constellation that the ancient Greeks called them Pleiades and they represented the seven daughters of Greek mythological figures Atlas and Pleione.

But you only see six stars. What about daughter #7? There are seven stars but only six are visible to the naked eye, so only six appear on the logo.

Alcyone is the “queen who wards off evil” and is the central and largest star of the Pleiades constellation.

Asterope is a double star in the Pleiades constellation whose name translates as “lightning.”

Merope is the only daughter to marry a mortal so she shines less brightly than her sisters.

Maia was the eldest and most beautiful. According to Greek myth, Maia was a lover of Zeus and gave birth to Hermes.

Zeus also defiled sister Taygeta while she was unconscious! She went into hiding and to protect her she was transformed into a doe.

Celaeno was married to Poseidon. Her name means “darkness” and this “Lost Pleiad” is sometimes difficult to see with the naked eye.

And finally, there is Electra whose name means amber, shining and bright. She was the wife of Corythus and was also seduced by Zeus – what a horrible god – and gave birth to Dardanus, who became the founder of Troy.

The Twins

Gemini symbol
Symbol for Gemini

Tonight and on the weekend, look at the waning gibbous Moon and you should be able to see two bright stars nearby. They are bright (unfortunately, so is the Moon now) and they appear so close together that we know them as The Twins.

They are Castor and Pollux in the constellation Gemini.

Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century AD astronomer Ptolemy, and it remains one of the 88 modern constellations today. Its name is Latin for “twins,” and it is associated with the twins Castor and Pollux in Greek mythology.

You should be able to see them (at least in mid-northern latitudes) over the eastern horizon around 9 p.m. and later from the Southern Hemisphere.

If you’re up before dawn,  the Moon and Gemini stars will be in the morning sky to the west.

Orion Rising

A beautiful view of Orion in a photo taken by Rogelio Bernal Andreo showing the surrounding nebulas of the Orion Molecular Cloud complex. Also captured is the red supergiant Betelgeuse (top left) and the famous belt of Orion composed of the OB stars Altitak, Alnilam and Mintaka. To the bottom right can be found the star Rigel.  via Wikimedia

The Full Moon of October is often called the Hunter’s Moon but Orion the Hunter is not limited to hunting in that month.

Orion is the first constellation I learned to spot in the night sky. It is very distinctive because of the short, straight row of three medium-bright stars at its mid-section that we call “Orion’s Belt.”

This constellation appears in the predawn sky in late July or early August. Now, in late August and early September, Orion the Hunter rises in the early hours of the morning (which many of us think of as night) and is up int the sky an hour before or at dawn.

But the shift continues and it will soon enough rise by midnight, then at my bedtime and by the time we reach the end of the year, Orion will be rising in the early evening. This shift from predawn to the evening sky is just like the westward shift of all the stars.  The shift is caused by Earth’s orbit around the sun which causes all the stars to rise approximately four minutes earlier each day.

Showing the stars and shape of Orion and his belt

Ursa Major Never Sets

The stars move with our seasons. For most of us, some move below the horizon and we lose sight of them for part of the year. But the circumpolar stars stay above the horizon all hours of the day, every day of the year. They are there now, even if it is daylight as you read this, they are there. there’s not a lot you can count on here on Earth – or even in the heavens – but you can count on them.

The Big Dipper asterism is the best known of the circumpolar groups at all latitudes north of 41 degrees north latitude. (That is the northern half of the mainland United States and most of Europe.)

The Big Dipper is part of a bigger constellation, Ursa Major or the Great Bear.

In Greek mythology, the god Zeus had fallen in love with the maiden Callisto. In a story that would make the news today, and get Zeus some bad headlines, Zeus got her pregnant. Callisto was a nymph in the retinue of the goddess Artemis. But she would not be with anyone but Artemis. Zeus disguised himself as Artemis and seduced Callisto. When the child Arcas was born, Zeus’ wife Hera turned Callisto into a bear in revenge.

Callisto wandered the forest for years in bear form, until a chance meeting with her son, Arcas. He was the king of Arcadia and a great hunter. He raised his spear to strike at the bear, not knowing it was his mother. Zeus stepped in and sent them up to the heavens with Callisto as the Great Bear and Arcas as Bootes the Herdsman. (Or maybe he is Ursa Minor, the Little Bear,  depending on whose mythology you follow.) Hera was not pleased that Zeus stepped in, so she wever, and conspired with the gods of the sea so that the Bear could never swim in the ocean. That is one explanation – totally unscientific – for why Ursa Major never sets

The Big Dipper is circumpolar, so it is visible year round. It is up in the spring and down in the fall. The pointer stars in the bowl of the Big Dipper always point to Polaris, the North Star |  |  Image via Chris Mihos, Department of Astronomy, Case Western Reserve University

Where are you? If you’re with me in the Northern Hemisphere, every star north of the celestial equator is circumpolar, and every star south of the celestial equator is below the horizon. At the Earth’s South Pole, every star south of the celestial equator is circumpolar, whereas every star north of the celestial equator remains beneath the horizon.

And at the Earth’s equator, no star is circumpolar because all the stars rise and set daily in that part of the world. You can actually see every star in the night sky over the course of one year.

The Moon, Jupiter and Spica

This past Memorial Day Weekend, we had some clear skies and some rainy ones. On one clear evening in Paradelle I was able to see a very bright “star” near the moon. It looks like a star, but it is Jupiter.

Venus sets in the west not too long after the sun sets, and the Moon and Jupiter were the two brightest objects in the sky.

I knew to look for a fainter true star. It is fainter but still one of the brightest stars, even in the moon’s glare. This is Spica. It is the brightest star in the constellation Virgo the Maiden. I’m not very knowledgeable about the zodiac, but I know it is a key star in that study.

Spica is a first-magnitude star, but it appears much fainter than Jupiter. That is because Jupiter is relatively close (or at least nearer)to Earth. This is what draws me to gazing at the night sky is my semi-knowledgeable way: the idea that Spica is about 262 light-years away, and I am looking at its light.

The universe makes me think about the original meanings of words like WONDERful and AWEsome.

Spica is the easiest star to spot in Virgo. There is a saying to find Spica you can “follow the arc of the Big Dipper to Arcturus and speed on to Spica.” But that probably doesn’t make it any easier for the average Earthling to find because most people know very little about the night sky.

Besides Spica, other bright stars in Virgo include many I had never heard of: β Virginis (Zavijava), γ Virginis (Porrima), δ Virginis (Auva) and ε Virginis (Vindemiatrix). Other fainter stars that were also given names are ζ Virginis (Heze), η Virginis (Zaniah), ι Virginis (Syrma) and μ Virginis (Rijl al Awwa).

Again, the wonder and awe of all this is discovering that one of the stars, 70 Virginis, has one of the first known extrasolar planetary systems and it contains a confirmed planet 7.5 times the mass of Jupiter. I can’t even really grasp the size of my own Earth. And the star Chi Virginis has one of the most massive planets ever detected, at a mass of 11.1 times that of Jupiter. And there are 35 verified exoplanets orbiting 29 stars in Virgo.

All this makes me feel like such a small part of the universe. But i also makes me feel part of the universe.


This first appeared on One-Page Schoolhouse