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Table of Contents
Metrological Units
- Barleycorn (sze): Defined as 1/180 of a cubit (kusz3). Originally taken from weight metrology, where 180 sze = 1 gin2.
- GAR: This equals 1/60 of a degree.
- Finger (szu-szi): In the OB period, there are 30 fingers in a cubit, while in the NB period there were 24.
- Degree (usz): This is a fundamental unit of measurement in astronomy. There are 12 fingers in a degree. One degree also corresponds to 4 minutes rotation time.
- Cubit (kusz3): This is a fundamental unit in length metrology. In Babylonian astronomy, it is given as either 30 fingers (OB) or 24 (NB).
- Double hour (danna): This corresponds to 30 degrees, or 12 cubits. It also equals 2 hours, hence the name.
Other units used for modern convenience
- Hour: This is half of a double hour, or 15 degrees.
- Large hour: Twice of a double hour.
- Day: Equal to 24 hours.
Names of the months
Month | Logogram | Month Name |
---|---|---|
I | bar | Nisannu |
II | gu4 | Aiaru |
III | sig | Simanu |
IV | szu | Duzu |
V | izi | Abu |
VI | kin | Ululu |
VII | du6 | Taszritu |
VIII | apin | Arahsamna |
IX | gan | Kislimu |
X | ab | T,ebetu |
XI | ziz2 | Szabat,u |
XII | sze | Adaru |
In addition, two intercalary months were used as needed. One was placed after month six, and written kin-2-kam (denoted here VI2), and the other after month twelve, written dirig or dir-sze (denoted XII2).
Signs of the Zodiac
Modern Name | Cuneiform designation |
---|---|
Aries | hun |
Taurus | mul2 |
Gemini | masz |
Cancer | kuszu2 |
Leo | a |
Virgo | absin |
Libra | rin2 |
Scorpius | gir2-tab |
Sagittarius | pa |
Capricorn | masz2 |
Aquarius | gu |
Pisces | zib |
Year notation
Years were denoted by whole numbers starting from…
Lunal ephemerides
The most commonly recorded observations of the Seleucid Period were the appearances of the new moon and full moon (sometimes called syzygies). These sightings determined the lengths of the months. In addition, several other statistics were measured such as the velocity, longitude, and latitude of the moon at time of syzygy, and the length of daylight on that day. Such data was used to predict solar and lunar eclipses whose occurrence held deep significance in ancient Mesopotamian cultures.
In Neugebauer's system of classification, there are two methods of computing ephemerides, which he names System A and System B.
System A
In this scheme the sun is presumed to move at one of two constant speeds on different arcs of the ecliptic.