Based on what a month determined as of a certain zodiac constellation?

Based on what a month determined as of a certain zodiac constellation?

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Since many of the 12 astrological signs (zodiacal constellations) may be visible in any single night, based on what is determined that this month (for 30 days!) is Capricorn, or Aquarius or Pisces etc.? Based on what in astronomy is this determined? What is the astronomical logic in it?

I've been told that the sun 'blocks' always one star constellation, so assuming the night is longer than the day (14-16 hours), and the earth rotates 15 degrees each hour and one star constellation appears while one disappears, it means that by 14 hours 6 'new' star consolations (that couldn't be visible at the beginning of the night) now can be seen along the night. This would mean that 12 star constellations may be visible every day (once 24 hours). If my reasoning is correct, what was the astronomic basis for the claim that one star constellations (out of the specific 12) is 'blocked' for one month?

The key coordinate is the Sun's geocentric ecliptic longitude: 0° at the March equinox, 90° at the June solstice, 180° at the September equinox, and 270° at the December solstice. The tropical zodiac subdivides each of these four 90° spans into three 30° blocks of ecliptic longitude. The Gregorian calendar is designed to keep the equinoxes and solstices near the same dates every year, so the dates the Sun passes through each sign are roughly the same each year too. The Sun spends 29.4 days in the sign of Capricorn and 31.5 days in the sign of Cancer because the Earth moves around the Sun faster at perihelion than at aphelion.

Signs and constellations are not the same. Over the centuries, precession has moved the signs 25°-30° west of the constellations they were named after. These modified Stellarium images show the zodiac in two halves, with the ecliptic and tropical sign boundaries in red, and the IAU constellation boundaries in blue.

Schedules of 30 or 31 days per sign are based on the 30° ecliptic longitude marks. Some astronomers promote another set of dates based on the IAU constellation boundaries, including the traditional twelve plus Ophiuchus. The time the Sun spends in each constellation ranges from 7 days in Scorpius to 44 days in Virgo. Precession shifts these dates 1.4 days later per century.

What is the astronomical logic in it?

Based largely on what Wikipedia says about the history of the zodiac it seems that the choice was made by Babylonian astronomers (and astronomy and astrology were heavily interwoven at that time) sometime during the rough period 1000 BC to 500 BC.

Wikipedia quote :

Around the end of the 5th century BC, Babylonian astronomers divided the ecliptic into 12 equal "signs", by analogy to 12 schematic months of 30 days each. Each sign contained 30° of celestial longitude, thus creating the first known celestial coordinate system. According to calculations by modern astrophysics, the zodiac was introduced between 409-398 BC and probably within a very few years of 401 BC.[10] Unlike modern astronomers, who place the beginning of the sign of Aries at the place of the Sun at the vernal equinox, Babylonian astronomers fixed the zodiac in relation to stars, placing the beginning of Cancer at the "Rear Twin Star" (β Geminorum) and the beginning of Aquarius at the "Rear Star of the Goat-Fish" (δ Capricorni)

Because the Babylonian astronomy and systems were passed to different cultures and were (presumably) the most developed, they became the foundation system for later systems from other cultures. Like so many "standards" they became too embedded to discard entirely.

Know Why There Will Always Be 12 Zodiac Signs

In the course of the most recent couple of years, the astrological community is hysterical over what could Perhaps be an identity crisis. NASA reported that Ophiuchus, an ancient constellation, exists in the ecliptic of the zodiac. So rather than the conventional 12 zodiac signs, it’s said there are thirteen Zodiac signs.

There is both good and awful news – the claim is both true and false. Here’s all that you have to know that will promise you that your zodiac identity isn’t in question.

12 Aries (March 21 - April 19)

Aries, the ram, can be seen in the first quadrant of the northern hemisphere between latitudes +90° and -60° and is best viewed during November. The constellation's main shape consists of three prominent stars, Mesarthim, Sheratan, and the brightest, Hamel. To locate Aries, look for a crooked line of three bright stars – Hamel (left), Sheratan (middle), Mesarthim (right).

For a bit of deep space exploration, within the constellation lies companion galaxies NGC 772 and NGC 770. Aries also plays host to several notable meteor showers throughout the year.

Star Constellations: The Zodiac

There are 88 modern constellations occupying different regions of the sky, with the 12 zodiac constellations situated within a 9° band either side of the ecliptic plane. This 18 ° wide imaginary line traces the apparent path that the Sun, Moon, and planets take over the course of a year. The ecliptic encircles the celestial sphere at an angle of 23.5° relative to the celestial equator. All the zodiac constellations located along this plane are subsequently visible to stargazers at different times of the year from latitudes of between +90° and -60°.

Astronomy & Constellations

In astronomy, the degrees of longitude marking each zodiac constellations are not equally sized. As such, the number of days the Sun spends in each zodiac constellation varies accordingly. This can be seen in the following list (days in brackets), which includes an unofficial thirteenth zodiac constellation called Ophiuchus, whose modern boundary also intersects the ecliptic:

Days the Sun spends in each Zodiac Sign

Sagittarius (32) Capricornus (23) Aquarius (24) Pisces (38) Aries (25) Taurus (37) Gemini (31) Cancer (20) Leo (37) Virgo (45) Libra (23) Scorpius (7) Ophiuchus (18).

Astrology & Zodiac Signs

In astrology, however, the zodiac constellations familiar to us as astrology signs are neatly divided into 12 segments of sky 30° of longitude wide. The Sun then spends around one month in each of the zodiac signs as it makes its annual trek across the sky.

A person’s ‘star sign’ is determined by which zodiac constellation the Sun is in front of at the time of their birth, as illustrated by the featured image above. But since the Sun appears in front of a zodiac constellation during the daytime, the sight is obscured from view. If we could see the stars during the daytime, though, we would see the Sun slowly drift from one zodiac constellation to the next over time, as it completes one full circle around the sky every year.

Due to precession, the zodiac constellation the Sun appears in front of during any month no longer corresponds to horoscope dates one reads about in the newspapers. The dates of astrology signs these days, instead, indicate where the zodiac constellation would have appeared several thousand years ago.

Zodiac Constellations


Capricornus (“sea-goat”) is the smallest of the 12 zodiac constellations. It is the 40th largest constellation in the night sky overall, taking up a 1.0% area of the celestial heavens. Capricornus is visible during the summer and autumn time from northern hemisphere locations. It is best seen during the month of September.

The brightest star in Capricornus is Deneb Algedi (Delta Capricorni), a multiple star system situated 39 light years from Earth that shines with an apparent visual magnitude of +2.85. Deep-Sky Objects (DSOs) in the constellation includes a globular cluster (Messier 30), a galaxy group (HCG 87), and some galaxies (NGC 7103, and NGC 6907). Meteor showers associated with Capricornus includes the Alpha Capricornids, Chi Capricornids, Sigma Capricornids, Tau Capricornids, and Capricorniden-Sagittarids.


Aquarius (“water-carrier”) is the 2nd biggest zodiac constellation. It is the 10th largest constellation overall, taking up a 2.4% area of the sky. Aquarius is visible during the autumn and winter time from northern hemisphere locations. It is best seen during the month of October.

The brightest star in Aquarius is Sadalsuud (Beta Aquarii), a yellow supergiant found 610 light years away with a visual magnitude of +2.91. Deep-Sky Objects (DSOs) in the constellation includes globular clusters (M2, M72), nebulae (NGC 7009, NGC 7293), and galaxies (PGC 65367, NGC 7252, NGC 7727). Meteor showers associated with Aquarius includes the March Aquariids, Eta Aquariids, and Iota Aquariids.


Pisces (“fishes”) is the 4th biggest zodiac constellation. It is the 14th largest constellation overall, taking up a 2.2% area of the sky. Pisces is visible in the northern hemisphere between late summer and winter. It is best seen during the month of November.

The brightest star in Pisces is Kullat Nunu (Eta Piscium), a yellow giant found 294 light years from Earth with a visual magnitude of +3.62. Deep-Sky Objects (DSOs) in the constellation includes numerous galaxies and galaxy groups (Messier 74, NGC 7537, NGC 383, PGC 4798, PGC 3792, NGC 7714 and NGC 7715, NGC 474, NGC 520, NGC 7459, NGC 514, NGC 57, NGC 60). Pisces has one meteor shower associated with it called the Piscids.


Aries (“ram”) is the 11th biggest zodiac constellation. It is the 39 largest constellation overall, taking up a 1.1% area of the sky. In the northern hemisphere, Aries is visible between winter and spring, although best seen during the month of December.

The brightest star in Aries is Hamal (Alpha Arietis), an orange giant 66 light years from Earth with a visual magnitude that ranges from +1.98 to +2.04. Deep-Sky Objects (DSOs) in the constellation includes a number of faint galaxies (NGC 772, NGC 1156, NGC 972, NGC 697). There are 5 meteor showers associated with Aries, the most important of which is the May Arietids, with the other weaker showers including the Autumn Arietids, Delta Arietids, Epsilon Arietids, and Daytime-Arietids.


Taurus (“bull”) is the 6th biggest zodiac constellation. It is the 17th largest constellation overall, taking up a 1.9% area of the sky. In the northern hemisphere, Taurus is visible during the autumn and winter time. It is best seen during the month of January.

The brightest star in Taurus is Aldebaran (Alpha Tauri), an orange giant 65.1 light years distant with a visual magnitude of +0.87. Deep-Sky Objects (DSOs) in the constellation includes nebulae (Messier 1, NGC 1555, NGC 1514), star clusters (Messier 45, Caldwell 41, NGC 1746, NGC 1647, NGC 1817, NGC 1807) and galaxies (NGC 1410 and NGC 1409. Taurus has two meteor shower associated with it called the Piscids. Meteor showers associated with Taurus includes the Taurids, and Beta Taurids.


Gemini (“twins”) is the 8th biggest zodiac constellation. It is the 30th largest constellation overall, taking up a 1.2% area of the sky. Gemini is visible during the winter to spring time from northern hemisphere locations. It is best seen during the month of January.

The brightest star in Gemini is Pollux (Beta Geminorum), an orange giant that is found 34 light years away with a visual magnitude of +1.14. Deep-Sky Objects (DSOs) in the constellation includes nebulae (NGC 2392, IC 443, Abell 21, NGC 2371-2), and star clusters (Messier 35, NGC 2158, NGC 2129, NGC 2355). There are two meteor shower associated with Gemini of opposite intensity, namely the prolific Geminids, and the unspectacular Rho Geminids.


Cancer (“crab”) is the 9th biggest zodiac constellation. It is the 31st largest constellation overall, taking up a 1.2% area of the sky. Cancer is visible during autumn to spring from northern hemisphere locations. It is best seen during the month of March.

The brightest star in Cancer is Al Tarf (Beta Cancri), an orange giant situated 290 light years away of magnitude +3.5. Deep-Sky Objects (DSOs) in the constellation include galaxies (NGC 2775, NGC 2535 & NGC 2536, NGC 2500, NGC 2608), and star clusters (Messier 44, Messier 67). The one meteor shower associated with Cancer is called the Delta Cancrids.

Leo (“lion”) is the 3rd biggest zodiac constellation. It is the 12th largest constellation overall, taking up a 2.3% area of the sky. Leo is visible during the winter to spring time from northern hemisphere locations. It is best seen during the month of April.

The brightest star in Leo is Regulus (Alpha Leonis), a multiple system lying 77 light years distant of magnitude +1.35. Deep-Sky Objects (DSOs) in the constellation include numerous galaxies (Messier 65, Messier 66, Messier 95, Messier 96, Messier 105, NGC 3628, NGC 3607, NGC 3593, NGC 3384, NGC 3842, NGC 3596, NGC 2903, NGC 3626, NGC 3357), as well huge quasar groups (CCLQG, Huge-LQG). There are four meteor shower associated with Leo, namely the famous Leonids, and the more minor Delta Leonid, Sigma Leonid, and Leo Minorids.


Virgo (“virgin”) is the largest zodiac constellation. It is also the 2nd largest constellation overall, taking up a 3.1% area of the sky. Virgo is visible during the spring and summer time from northern hemisphere locations. It is best seen during the month of May.

The brightest star in Virgo is Spica (Alpha Virginis), a multiple system situated 260 light years away of magnitude +1.04. Deep-Sky Objects (DSOs) in the constellation include numerous galaxies (Messier 49, Messier 58, Messier 59, Messier 60, Messier 61, Messier 84, Messier 86, Messier 87, Messier 89, Messier 90, Messier 104, NGC 4435 & NGC 4438, NGC 4216, NGC 4567 & NGC 4568, NGC 4526, NGC 4261), and a quasar called 3C 273. The two meteor shower associated with Virgo includes the Virginids, and the Mu Virginids.


Libra (“weighing scales”) is the 7th biggest zodiac constellation. It is the 29th largest constellation overall, taking up a 1.3% area of the sky. Libra is visible during the spring and summer time from northern hemisphere locations. It is best seen during the month of June.

The brightest star in Libra is Zubeneschamali (Beta Librae), a blue-white dwarf lying 185 light years away of magnitude +2.61. Deep-Sky Objects (DSOs) in the constellation includes galaxies (NGC 5792, NGC 5890, NGC 5897, NGC 5885), and the globular cluster NGC 5897. The one meteor shower associated with Libra is called the May Librids.


Scorpius (“scorpion”) is the 10th biggest zodiac constellation. It is the 33rd largest constellation overall, taking up a 1.2% area of the sky. Scorpius is visible during the summer time from northern hemisphere locations. It is best seen during the month of July.

The brightest star in Scorpius is Antares (Alpha Scorpii), a red supergiant found 550 light years from Earth that shines with a visual magnitude of +0.96. Deep-Sky Objects (DSOs) in the constellation include several star clusters (Messier 4, Messier 6, Messier 7, Messier 80, NGC 6281, NGC 6124, NGC 6231), and nebulae (NGC 6334, NGC 6072, NGC 6302, NGC 6357). Meteor showers associated with Scorpius includes the Alpha Scorpiids, and the Omega Scorpiids.


Sagittarius (“archer”) is the 5th biggest zodiac constellation. It is the 15th largest constellation overall, taking up a 2.1% area of the sky. Sagittarius is visible during the autumn time from northern hemisphere locations. It is best seen during the month of August.

The brightest star in Sagittarius is Kaus Australis (Epsilon Sagittarii), a binary system located 140 light years distant with a visual magnitude of + 1.85. Lying in a dense part of the sky, Sagittarius is rich in deep-sky objects (DSOs) , including nebulae (Messier 8, Messier 17, Messier 20, NGC 6565, NGC 6578, Hubble 1925 I, NGC 6818, M 1-42, NGC 6589, Henize 3-1475, Westerhout 5, NGC 6537, NGC 6559), galaxies (Sgr dSph, Sag DIG, NGC 6822), and the molecular cloud Sagittarius B2.

It also contains numerous star clusters (NGC 6530, Messier 18, Messier 21, Messier 22, Messier 23, Messier 24, Messier 25, Messier 28, Messier 54, Messier 55, Messier 69, Messier 70, Messier 75, Arches Cluster, Quintuplet Cluster, NGC 6522, NGC 6528, NGC 6723, NGC 6544, 1806-20, Terzan 7, Terzan 5, NGC 6440, NGC 6445, NGC 6638, NGC 6624, NGC 6520, NGC 6717, Hurt 2, NGC 6553, NGC 6774, NGC 6558, NGC 6569, NGC 6540). There are no meteor showers associated with Sagittarius.

Zodiac signs are off by a month, expert says

Hey there, what's your sign? Are you sure about that?

It seems that many of us may not be the Leos or Geminis we thought we were, thanks to a wobble in the earth's axis. According to a report in the Minneapolis Star-Tribune, all of the zodiac signs are off by about a month.

Your astrological sign can be determined by the position of the sun relative to certain constellations on the day you were born. But the astrological positions were calculated some 2,000 years ago.

The Star-Tribune spoke to Parke Kunkle, an astronomy professor at Minnesota Community and Technical College, and aboard member at the Minnesota Planetarium Society, who says that in the centuries since those calculations were made, the moon's gravitational pull has made the Earth "wobble" around its axis.

It's a well-known phenomenon called "precession." This "wobble" causes a change of one degree every 70 years in our view of the stars. The change is so small it is hardly noticeable, but after 2,000 years, it's added up.

While it's all a little complicated, the bottom line is there's been about a one-month bump in the alignment of the stars. And that's made a mess of astrology.

"When [astrologers] say that the sun is in Pisces, it's really not in Pisces," the Minnesota Planetarium Society Parke Kunkle told the newspaper.

According to Kunkle, there really should be a 13th sign, Ophiuchus. It seems the Babylonians who invented the zodiac skipped Ophiuchus because they wanted only 12 signs. Now that the Earth has rotated, here is apparently where the real signs of the zodiac should fall:

  • Capricorn: Jan. 20-Feb. 16
  • Aquarius: Feb. 16-March 11
  • Pisces: March 11-April 18
  • Aries: April 18-May 13
  • Taurus: May 13-June 21
  • Gemini: June 21-July 20
  • Cancer: July 20-Aug. 10
  • Leo: Aug. 10-Sept. 16
  • Virgo: Sept. 16-Oct. 30
  • Libra: Oct. 30-Nov. 22
  • Scorpio: Nov. 23-29
  • Ophiuchus: Nov. 29-Dec. 17
  • Sagittarius: Dec. 17-Jan. 20

If you're a former Scorpio or Sagittarius who now finds yourself under Ophiuchus, here's what you need to know. The sign is based on the constellation of the same name said to represent the healer Asclepius, son of Apollo, holding two snakes.

Ophiuchus is thought to attract good luck and holds lofty ideals, while seeking peace and harmony. Those born under the Ophiuchus sign are said to be curious, passionate, with a thirst for knowledge and sometimes, an explosive temper.

The Star-Tribune story of the zodiac shake-up has spread around the Internet quickly, sending panic through the hearts of true astrology believers who have found themselves in an astrological identity crisis.

But some are insisting that if you're worried that you're no longer the fun-loving Libra you thought you were, and are really a perfectionist Virgo, be assured that nothing has changed.

That's because there are actually two zodiacs.

The form of astrology that calculates zodiac signs based on constellations -- called the sidereal zodiac -- is followed more in the East, not here in the West. Western astrology -- and, most likely, the horoscope writers in your local newspaper -- adhere to the tropical zodiac, which is fixed to seasons and the equinoxes.

According to the tropical zodiac, nothing has changed, the Earth's axis notwithstanding.

So keep being that great listener, Libra, and don't worry that you've morphed into a Virgo.

Parke Kunkle, who teaches astronomy at Minneapolis Community and Technical College, talks with a reporter about changing astrological signs in his office in Minneapolis, Minn., Friday, Jan. 14, 2011. (AP / Craig Lassig)

What's your sign? It seems that many of us may not be the Leos or Geminis we thought we were, thanks to a wobble in the earth's axis. (AP / Uncommon Goods)

Difference Between Zodiac and Constellation

Constellations are defined as a group of stars which form a particular pattern and are named and identified by their traditional mythological figures. Zodiacs are also constellations, but all constellations are not zodiac constellations. Zodiacs constellations are the specific 12 constellations which are passed by the sun once a year. Zodiac constellations are the constellations which give the zodiac signs to people.

Constellations are groups of stars that form a specific pattern and are recognized by mythological figures and have names attributed to them. Constellations are used for the study of astronomy. According to modern astronomy, the constellations are defined and recognized areas of the sphere called the celestial sphere. These defined areas or constellations are internationally recognized. When prominent stars which are at a certain proximity to the other stars are grouped around an asterism in the night sky of Earth, they form constellations.

There are many different constellations recognized by different cultures all over the world like Chinese, Hindu, Australian Aboriginal, astrology, and astronomy, but only 88 are considered the standard constellations recognized by the IAU, International Astronomical Union since 1922. Originally, 48 constellations had been defined and recognized by Ptolemy in the 2nd century. The majority of the 88 constellations have been taken from Ptolemy. The rest were recognized in the 17-18th centuries. Most of the recent constellations were found and defined by Nicolas Louis de Lacaille which are situated in the southern sky. Examples of some constellations are Orion, Sirius, etc.

Zodiac constellations are a series of 12 particular constellations which are internationally recognized across which the sun, moon, and the stars move. The path along which the sun moves through the zodiacs is called the ecliptic. The ecliptic has been divided into 12 equal zones. These 12 zones are passed through by the sun at different times of the year just once, and the months through which the sun passes through them are attributed with a zodiac sign, for example, Aries or Cancer, etc.

Zodiacs were used by the Romans in the 1st millennium BC. The concept had been taken from Babylonian astronomy which was derived from Ptolemy’s study of the stars and the list of the groups of stars he had identified and named.
The word “zodiac” was derived from Latin word “zodiacus,” which was derived from the Greek word “zoidiakos” meaning “circle of animals.” That is why a lot of zodiac signs are represented by mythological hybrid animals.

1.Zodiac constellations are 12 specific constellations which have been picked because they help in keeping time as the sun passes through them once a year, and its passage within a certain time is considered the particular zodiac month. 2.Zodiac constellations help in representing the course of the sun through the whole year or the calendar. All zodiacs are constellations, but all constellations are not zodiac constellations.

Zodiac in the Medieval Ages

Scientific researches of the zodiac, as well as astronomy development in general, were not so significant in Medieval Europe. While it was one of the main scientific issues in Asia, in Europe astronomy had far not the best period. The Medieval Ages in Europe in this sphere can be characterized as returning to Greek and Roman magic. Close attention was paid to the magical functions of the zodiac. Many people tried to learn more about astrology because they believed that it would be possible to predict the future.

From a scientific point of view, a lot of Arabic works were translated and analyzed by European researchers of those days. Then the Zodiac started to be applied as a so-called décor. For instance, it could be noticed in Angers Cathedral. Another significant cultural asset is a set of silver and gold coins on which twelve zodiacal signs were featured. It was created by the king of Mughal Jahangir. Other names of astronomers and astrologers include Italian scientist Guido Bonatti and a monk from Britain Johannes de Sacrobosco.

Zoroastrian (Persian) Astrology & Cosmology

Each arc contains a named group of stars called a named constellation or group of prominent stars. The twelve constellations, dwazdah-akhtaran, together make up the Zoroastrian (and other) zodiac (Middle Persian, dwazdahan Modern Persian, زودیاک zudik). The constellation were seen as bayan, givers of beneficence while planets could portend harmful change or reduce the beneficence of the constellations.

It is commonly understood that the term zodiac derives from Latin "zōdiacus" which means a circuit. One theory is that zodiacus derives from the Greek term ζῳδιακὸς κύκλος (zōdiakos kuklos), meaning "circle of animals", in turn derived from ζώδιον (zōdion), a small animal [ζῶον (zōon)] and zoion, living being. Another theory is that zodiacus derives from the Greek word "zoad" meaning the way or a step referring to the passage of the sun through these arc of the Zodiac.
The ecliptic belt containing the constellations that make up the Western Zodiac

Constellations & the Celestial Sphere
The Zodiac consists of twelve constellations, the Dwazdah-Akhtaran, a discernible group of stars that from a pattern.There are 88 constellations. The Greek poet Aratus of Soli (c. 315-c. 245 BCE) described 44 constellations in his Phaenomena. Ptolemy described 48 constellations in his Almagest, 47 of which are known today by their same names. Western representations of the constellations are similar to Iranian-Persian and Indian representations. Some Chinese representations are similar as well. Since the representations are imaginary, the similarities are more than coincidence.

Varak (Aries)
When the Zoroastrian zodiac was last assembled, the first degree of Varak the ram (known in the West as Aries) marked the start of vernal or spring equinox, the first day of spring in the northern hemisphere.

The Size of the Zodiac Sectors
According to the Greater Bundahishn (GB 2.6) the cosmos was fashioned in the semblance of a (solar) year and that each of "the twelve constellations, like twelve months, have thirty degrees just as every month has thirty days."

We note in our page on World Horoscope that the signs of the zodiac do not form 'houses' in themselves, but rather occupy 'houses' or sectors. Therefore, in the Zoroastrian zodiac, the size of the sectors or houses are fixed and do not vary with the size of the constellations that occupies it at a particular point in history. This is an important and critical difference in concept with other concepts of the zodiac.

In Western astrology, there are different ways of measuring the size of a sign of the zodiac, with some systems using the 30° rule while others adopt a variable size corresponding to the size of the associated constellation. As a group of stars, Aries fits within the sector boundaries of the 30° arc that defines the boundaries of its arc sector. While Aries and some other signs fit within the boundaries of their arcs, others like Pisces stretch beyond a 30° arc.

Time as in a calendar is defined and measured by the constellation occupying a sector at a point in time and by the position of the Sun in that 'house'.As such, the constellation of the zodiac is not the primary source of the properties of a sector or 'house'. Rather, they are a secondary source. The primary properties are defined by the name given to the sector and are constant. They are not subject to precession.

In Zoroastrian astrology "each month belongs to a constellation" (GB 6B.2), and each constellation is represented as a sign of the zodiac. The twelve signs of the Zodiac used in Zoroastrian & Western astrology and their Gregorian calendar dates were (for the Age of Aries i.e. 2150 BCE-1 CE):
Gregorian Dates - Zoroastrian Calendar Zoroastrian Zodiac Names Western Zodiac Name Gregorian Dates
Mar 21-Apr 19 Varak/Warrag (lamb/ram). Aries Mar 21-Apr 18/20
Apr 20-May 19 Tora/Gav (bull/ox/cattle) Taurus Apr 19/21-May 20/21
May 20-Jun 18 Dopatkar/Do-pahikar (two figures/images) Gemini May 21/22-Jun 20/22
Jun 19-Jul 18 Kalakang/Karzang (crab) Cancer Jun 21/23-Jul 22/23
Jul 19-Aug 17 Ser/Shagr (lion) Leo Jul 23/24-Aug 22/23
Aug 18-Sep 16 Khusak/Hushag (ear of grain) Virgo Aug 23/24-Sep 22/23
Sep 17-Oct 16 Tarazuk/Taragug (balance/scales) Libra Sep 23/24-Oct 22/23
Oct 17-Nov 15 Gazdum (scorpion) Scorpio Oct 23/24-Nov 21/22
Nov 16-Dec 15 Nimasp/Nemasp (centaur) Sagittarius Nov 22/23-Dec 21/22
Dec 16-Jan 14 Vahik/Wahig (goat) Capricorn Dec 22/23-Jan 19/
Jan 15-Feb 13 Dul/Dol (water spout/pail) Aquarius Jan 20-Feb 18/19
Feb 14-Mar 15 Mahik/Mahig (fish) Pisces Feb 19/20-Mar 20
Mar 16-Mar 20 Hamaspath-maidyem (mid path of all) Pisces
For the Zoroastrian Zodiac names written in Old Persian cuneiform, please see the bottom of the page.
Classical depiction of the signs of the zodiac. The inner circle contains the hieroglyph of Hemphta, the triform and pantamorphic deity. In the six concentric bands surrounding the inner circle are (from within outward): (1) the numbers of the zodiacal houses in figures and also in words (2) the modern names of the houses.(3) the Greek or the Egyptian names of the Egyptian deities assigned to the houses (4) the complete figures of these deities (5) the ancient or the modem zodiacal signs, sometimes both (6) the number of decans or subdivisions of the houses.
Image and caption credit: Kircher’s Œdipus Ægyptiacus at the Living Prophecy.
Image below: Age of Pisces. Sun currently rises in the zodiac constellation Pisces on the vernal equinox, March 21. For current Age of Pisces associations, see our page Horoscope Qualities.
Vernal Equinox 2007 and constellations of the zodiac. Note the west to east order of the constellations. When the Sun rises in a particular constellation (here Pisces), it stays in that sign for the rest of the day and the entire constellation rotates east to west along with the Sun. We are currently in the Age of Pisces. Image credit: Covertress.

Zodiac Signs and the Zodiac Sectors of the Ecliptic
As we have noted above, since the constellations of the zodiac are of varying sizes, there are at times gaps between the constellations and at times they overlap. In addition, since the sectors of the ecliptic based on a month of 30 days is fixed at 30°, at times the constellations of the zodiac run over the boundaries of a sector and at times fit with space to spare.
The constellations and signs of the zodiac overlaid on a horoscope circle with twelve sectors of 30 degrees each.
Image credit: John
The signs of the zodiac. Image credit: Merriam-Webster

The twelves signs of the zodiac are divided into four triplicities/trigons, each made of three constellations separated from each other by 120 degrees.

Fire: Aries, Leo and Sagittarius
Earth: Taurus, Virgo, Sagittarius
Air: Gemini, Libra and Aquarius
Water Trigon: Cancer, Scorpio and Pisces

More than 4,000 years ago, astronomers wondered how the sky would appear if the stars could be seen during the daytime. Based on their observations of the night sky, some astronomers determined that during the daytime, the Sun would appear to 'enter' or reside in a sector occupied by a different constellation each month. (This would be because the constellation would stay directly behind the Sun and as the earth continued to move along its orbit, the line of vision from the earth would see another constellation appear behind the Sun.)

Constellations of the zodiac along the ecliptic behind the Sun. Image credit: Encyclopedia of Science
However, we cannot directly observe this phenomenon since the brightness of the Sun hides all view of the constellations and their stars. However, the neighbouring constellations on both sides can be observed in a clear sky just before dawn and just after Sunset. From knowing the positions of the constellations during the night, it is possible to determine the position of the Sun in a particular constellation, or rather, the sector occupied by a constellation each month.
Zodiac Constellation and a time map. Note anticlockwise progression of the constellations
but a clockwise progression of the years.
Image Credit Drunken Astrology

Birth & Ascendant Sign
In Western astrology and horoscopes, a birth sign is the sign which the Sun occupied on a person's birthday. It is also called the Sun sign.

The ascendant or rising sign is the sign rising over the eastern horizon at the time of a person's birth. See the previous tab "Cosmos" for a more complete definition.

Zodiac Signs By Months and Dates - Zodiac Calendar 2021

Your zodiac signs are the mirror of your personality. These are your birthday signs that tell who you are by birth and what characteristics you possess from the time you were born. By understanding zodiac sign meaning, you may know about your personality traits and explore the strengths and weaknesses. It is believed that astrology signs of zodiac can help you to know how your life partner is and what is your zodiac compatibility with him/her.

As per Western astrology, Zodiac signs are based on the range of dates that lasts for a month. Each zodiac sign has their own birth date ranges and if you fall in that specific range, you are considered the member of that zodiac sign.

So, if you want to know what your zodiac sign is and what kind of personality you have, you may check the date range of the zodiac sign and easily get an idea of the astrology sign that influences your personality.

Are you a true Aries or Taurus or born on zodiac cusp? Talk to astrologer and find your accurate zodiac sign by date of birth. Get insights into your zodiac personality and explore a lot more about upcoming prospects on live chat astrology consultation.

The Thirteenth Month and the Constellation Ophiuchus

Despite the common idea that each of the above groupings has twelve items (cf. Echad Mi Yodeah…) there are actually thirteen in each of them! Well, at least sometimes, or from a certain point of view…

When I was a student in yeshivah, one of my rabbis, Rav Rivlin, shlita, was discussing the association of the months of the Jewish calendar with the Tribes of Israel, and asked which month is connected to Yosef – Joseph? I had a sudden flash of insight and answered: Adar – because sometimes it is one and sometimes it’s split into two, just like Joseph. Sometimes Joseph is counted as one tribe and sometimes (more often) counted as two, Ephraim and Menasheh. Similarly, the month of Adar is in most years one month, but in leap years – such as right now – there is Adar Rishon and Adar Sheini. With respect to most halachot – like celebrating Purim – Adar Sheini is considered the “real” Adar because it is the one that comes right before Nisan and Adar Rishon is the extra one.

In a vaguely similar way, the Constellations of the Zodiac are also generally counted as twelve – but there are really thirteen! Ophiuchus is the unknown one you’ve probably never heard of Ophiuchus, right…?

The Constellation Ophiuchus

But first, what is the Zodiac? While ascribing no power or validity to astrology (which is not a science), astronomers do refer to the Zodiac as a band of constellations that cross (or contain part of) the ecliptic – the Sun’s apparent annual path around the sky.

Celestial Sphere model of sky, showing constellations and the ecliptic – the Sun’s apparent path through Zodiac

Diagram of Constellations of the Zodiac and apparent relative position of the Sun and Earth throughout the year.

Now, Ophiuchus: This constellation is generally referred to as a Snake charmer, after a medieval Islamic attribution. The ancient Greeks and Romans thought of various identities of the constellation (including Apollo and Asclepius) all of which are somebody holding or struggling with a snake (the adjacent constellation Serpens.) Although the constellation stretches far to the north and south, it intersects a relatively small portion of the ecliptic, between Scorpius and Sagittarius.

Ophiuchus in a manuscript copy of Azophi’s Uranometry, 18th-century copy of a manuscript prepared for Ulugh Beg in 1417. Ophiuchus holding the serpent, Serpens, as depicted in Urania’s Mirror, a set of constellation cards published in London c. 1825.

Not including Ophiuchus, the constellations of the Zodiac are generally associated with the months of the Hebrew calendar, despite it being a lunar calendar.

For those who may not be familiar with the mechanics of the Jewish Calendar here is a brief description: It is a Lunar-solar calendar (or “corrected” Lunar calendar, similar to the Chinese/Asian calendar – BTW Happy New Year of the Monkey!) Months are either 29 or 30 days long so as to roughly correspond to the Lunar cycle of 29.5 days. There is a 19 year leap year cycle (as per the Metonic cycle, named after the Greek astronomer Meton of Athens but known to many ancient cultures) in which there are 12 months in most years, but in 7 out of 19 years, we add a “leap month” for a total of 13 months.

This calendar has been in use by Jews since roughly the 4 th Cen. CE and is generally attributed to Hillel II. Before then, things were not so simple. The more ancient Jewish “calendar” used before the 4th Century was not really a “calendar” in the way we think of them at all. It was a system for determining months and years based on witnessing the new moon (by 2 witnesses) and testifying before the Sanhedrin, the “Supreme Court”, which, after cross-examining the witnesses, declared (or “sanctified”) the new month.

In a similar manner, the Court would determine whether or not to add an extra “leap” month to a given year, based on several relevant factors, as discussed in Tractate b. Sanhedrin (11b-12a):

תנו רבנן על שלשה דברים מעברין את השנה על האביב ועל פירות האילן ועל התקופה על שנים מהן מעברין ועל אחד מהן אין מעברין

Our Rabbis taught: A year may be intercalated on three grounds: on account of the premature state of the grain-crops or that of the fruit-trees or on account of the lateness of the Tekufah Any two of these reasons can justify intercalation, but not one alone.

Other factors were also considered:

תנו רבנן אין מעברין את השנה אלא אם כן היתה צריכה מפני הדרכים ומפני הגשרים ומפני תנורי פסחים ומפני גליות ישראל שנעקרו ממקומן ועדיין לא הגיעו אבל לא מפני השלג ולא מפני הצינה ולא מפני גליות ישראל שלא עקרו ממקומן ת”ר אין מעברין את השנה לא מפני הגדיים ולא מפני הטלאים ולא מפני הגוזלות שלא פירחו אבל עושין אותן סעד לשנה

Our Rabbis taught: A year may not be intercalated except where it is necessary either for [the improvement of] roads or for [the repair of] bridges, or for the [drying of the] ovens [required for the roasting] of the paschal lambs, or for the sake of pilgrims from distant lands who have left their homes and could not otherwise reach [Jerusalem] in time. But no intercalation may take place because of [heavy] snows or cold weather or for the sake of Jewish exiles [from a distance] who have not yet set out.

Our Rabbis taught: The year may not be intercalated on the ground that the kids or the lambs or the doves are too young. But we consider each of these circumstances as an auxiliary reason for intercalation.

However, the rabbinic court could not make these determinations too early in the year (or in the previous year):

ת”ר אין מעברין את השנה לפני ראש השנה ואם עיברוה אינה מעוברת אבל מפני הדחק מעברין אותה אחר ראש השנה מיד ואעפ”כ אין מעברין אלא אדר

Our Rabbis taught: The year may not be intercalated before the New Year, and if it be intercalated, the intercalation is invalid. In case of necessity, however, a year may be intercalated immediately after the New Year yet even so, only a [second] Adar is added.

We see here that “leap” months are always added as an additional Adar. However, their addition could not be decided/ruled on before Tishrei. There seems to be a “half-year” that is the bounds of “leap month adding” – the court cannot make a ruling before Tishrei and the doubled month itself is always Adar.

Ophiuchus, is an almost unknown zodiacal constellation that occurs within this “half-year”. It could perhaps be viewed as the extra month’s constellation – at least homiletically – although it is not actually aligned with the Sun during Adar. (Note that there is no extra “distance” due to there being seven constellations in one “half-year” the Sun still passes through 180 degrees in each half of a yearly cycle – e.g. from equinox to equinox or solstice to solstice.)

Although it does not directly correspond to Adar in order, if you’re going to add an additional Adar and you want the constellation associated with the “regular” (i.e. second) Adar to line up with it as usual, and you only determine this in Tishrei or later, then the “extra” constellation has to be between Libra (Tishrei) and Pisces (Adar).

Furthermore, Tishrei is the earliest that the court could decide to declare a leap month, but not the latest. The rabbinic considerations involved the spring produce and fruit trees. These would perhaps be more easily or accurately predicted in the autumn if they were to wait until seeing whether the rainy season began “on time” in Marcheshvan. Thus the Sun might often be “in Ophiuchus” right around that time (after Scorpius which corresponds to Marcheshvan) that the court was making its decision. This would have been even more astronomically prominent 2-3 millenia ago, since the Earth’s precession (see my earlier post on that) has caused the dates of the Sun’s passing through each constellation to have shifted over time. Back then, the Sun would have crossed Ophiuchus around a month earlier than today – in Marcheshvan (roughly, since the months are lunar the exact Hebrew dates of the Sun’s crossing a constellation will always vary from year to year.)

During a leap year in which there is an extra month, from Marcheshvan through Adar, for the first “half-year” – the part that contains Ophiuchus – we add “u’l’kapparat pasha’” – “for the atonement of transgression” to the mussaf (additional) prayer said on Rosh Chodesh – the New Moon:

חַדֵּשׁ עָלֵֽינוּ אֶת־הַחֹֽדֶשׁ הַזֶּה לְטוֹבָה וְלִבְרָכָה לְשָׂשׂוֹן וּלְשִׂמְחָה לִישׁוּעָה וּלְנֶחָמָה לְפַרְנָסָה וּלְכַלְכָּלָה לְחַיִּים וּלְשָׁלוֹם לִמְחִֽילַת חֵטְא וְלִסְלִיחַת עָוֹן [ וּלְכַפָּרַת פֶּֽשַׁע ] ( אָמֵן

Renew for us this month for good and blessing, for joy and happiness, for salvation and consolation, for sustenance and commerce, for life and peace, for annulment of sin and forgiveness of iniquity [ and for the atonement of transgression.]

One could easily wonder “why?” What does being a leap year have to do with praying for a bit of extra atonement? And why only during the months between Marcheshvan and Adar (inclusive)?

If you studied at Kerem B’Yavneh, you surely remember Rav Rivlin’s shiur (class) on Purim and the Sense of Smell (Purim v’Chush Hareach). In this class – whose title may sound like “Purim Torah” but whose context is serious – he focused on the aggadah connection between Adam and Eve’s first sin, the primordial Snake and Purim. Without explaining the overarching titular connection to the sense of smell, one essential point made is that Purim – which, of course, falls in Adar – is, or can be, a “corrective” to the sin of Adam and Eve that was caused by the Snake. Haman is (by some) thought to be the “gilgul” (roughly, “reincarnation” perhaps to be viewed more metaphorically) of the Snake, loosely supported by this Talmudic wordplay (b. Hullin 139b):

המן מן התורה מנין (בראשית ג) המן העץ אסתר מן התורה מנין (דברים לא) ואנכי הסתר אסתיר מרדכי מן התורה מנין דכתיב (שמות ל) מר דרור ומתרגמינן מירא דכיא

Where is Haman indicated in the Torah? — In the verse: Is it [hamin] from the tree? Where is Esther indicated in the Torah? — [In the verse,] And I will surely hide [asthir] my face. Where is Mordecai indicated in the Torah? — In the verse: Flowing myrrh, which the Targum renders as mira dakia.

The verse on which the pun “Hamin ha’etz” -”from the tree?” is quoted in relation to Haman is from God’s question to Adam & Eve when confronting them after they have sinned: “ Have you eaten from the tree that I commanded you not to eat from?” (Genesis 3:11)

Whether to think of this as a proof text or a pun notwithstanding, there is certainly an allusion here connecting Haman with the Snake-incited first sin.

Both Haman and the Snake seem to have shared a bad character trait of envy and/or egomania. Neither of them could tolerate the idea that there was a single person who might be greater than themselves. Haman was incensed by Mordechai’s refusal to bow to him. Likewise, one possible explanation of the Snake’s motive seems to be that he was “out to get” Adam & Eve because he could not tolerate that there was one creation – humanity – more lofty than himself. (Recall that he also had the power of speech, as humans do, and before God’s punishment perhaps walked on legs – see Rashi on Genesis 3:14)

All this can possibly help to elucidate the addition of the phrase “u’lkapparat pasha’” (or maybe not you can be the judge…) The constellation Ophiuchus is perhaps somehow associated with the addition of Adar Sheini in leap years, and is relevant between Marcheshvan and Adar, as discussed. Furthermore, Ophiuchus is a snake charmer, or other snake-related or snake defeating character. Adar is the month of Purim, in which there is a reappearance of the Snake as the enemy Haman. (Note that a similar connection between the Snake from Genesis 3 and Ophiuchus – not including Adar or Haman – is made in Edward Maunder ’s Astronomy of the Bible , 1908, pp. 163-164, albeit with some non-Jewish ideas as well.)

Notice also that Haman’s plan to destroy the Jews was intended to take place on the 13th of Adar. If that were a leap year, it would have been the 13th of the 13th month…? Is there any significance to this? (Your guess is as good as mine…)

Esther instructed the Jews to pray for her before attempting her plan to approach the King, by which the envious egomaniac Haman’s plan was defeated.

May this connection – tenuous though it may seem to some – serve as a further reminder when we pray for “kapparat pasha’” that Adar is a propitious month(s) to pray that we atone for the sin of Adam and Eve and thus defeat the Snake’s and Haman’s evil designs – by subduing our own ego and any envious tendencies we may have.