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© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
E. Boutsikas et al. (eds.), Advancing Cultural Astronomy, Historical & Cultural
Astronomy, https://doi.org/10.1007/978-3-030-64606-6_3
Their Equinox: Mesopotamian
Conceptions of Solstices and Equinoxes
John Steele
1 Introduction
In his well-known 1997 article “Whose Equinox?”, Clive Ruggles highlights a significant methodological problem within archaeoastronomy: the imposition of modern (Western) ideas of what constitutes a significant astronomical event upon ancient
and/or non-Western cultures (Ruggles, 1997). To illustrate his point, Ruggles takes
the example of the equinox. Archaeoastronomers, and, according to Ruggles,
increasingly archaeologists, have frequently claimed that various monuments,
buildings, etc., possess “equinoctial alignments”, tacitly understood to be the direction towards either the position on the eastern horizon at which the sun rises or the
position on the western horizon at which the sun sets at the equinox. But as Ruggles
points out, it is important to examine closely what we mean by an “equinoctial
alignment”, or, more fundamentally, what we mean by an “equinox”. And, perhaps
even more importantly, whether the culture we are studying had the same interpretation of what an equinox is as our modern definition and, indeed, whether the equinox was a meaningful and significant concept at all within their worldview.
In modern astronomy, an equinox is defined as the moment at which the sun
crosses the celestial equator. At that moment, the sun will have a declination of 0°,
day and night will be of equal length, and, assuming a perfectly flat horizon, the sun
will rise due east and set due west. In fact, only the first of these statements is accurate in practice. Because the sun reaches the equinox at a precise moment and continues to move after it has reached it, day and the following night will only be equal
if the moment of equinox coincides with the moment of sunset (and even this is not
precisely true because the sun’s speed is not constant); similarly, the sun will only
rise precisely due east if the equinox occurs exactly at sunrise and only set due west
J. Steele (*)
Department of Egyptology and Assyriology, Brown University, Providence, RI, USA
e-mail: john_steele@brown.edu
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
E. Boutsikas et al. (eds.), Advancing Cultural Astronomy, Historical & Cultural
Astronomy, https://doi.org/10.1007/978-3-030-64606-6_3
Their Equinox: Mesopotamian
Conceptions of Solstices and Equinoxes
John Steele
1 Introduction
In his well-known 1997 article “Whose Equinox?”, Clive Ruggles highlights a significant methodological problem within archaeoastronomy: the imposition of modern (Western) ideas of what constitutes a significant astronomical event upon ancient
and/or non-Western cultures (Ruggles, 1997). To illustrate his point, Ruggles takes
the example of the equinox. Archaeoastronomers, and, according to Ruggles,
increasingly archaeologists, have frequently claimed that various monuments,
buildings, etc., possess “equinoctial alignments”, tacitly understood to be the direction towards either the position on the eastern horizon at which the sun rises or the
position on the western horizon at which the sun sets at the equinox. But as Ruggles
points out, it is important to examine closely what we mean by an “equinoctial
alignment”, or, more fundamentally, what we mean by an “equinox”. And, perhaps
even more importantly, whether the culture we are studying had the same interpretation of what an equinox is as our modern definition and, indeed, whether the equinox was a meaningful and significant concept at all within their worldview.
In modern astronomy, an equinox is defined as the moment at which the sun
crosses the celestial equator. At that moment, the sun will have a declination of 0°,
day and night will be of equal length, and, assuming a perfectly flat horizon, the sun
will rise due east and set due west. In fact, only the first of these statements is accurate in practice. Because the sun reaches the equinox at a precise moment and continues to move after it has reached it, day and the following night will only be equal
if the moment of equinox coincides with the moment of sunset (and even this is not
precisely true because the sun’s speed is not constant); similarly, the sun will only
rise precisely due east if the equinox occurs exactly at sunrise and only set due west
J. Steele (*)
Department of Egyptology and Assyriology, Brown University, Providence, RI, USA
e-mail: john_steele@brown.edu