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Date and Constellation Location for Vernal Equinox in 3000 BCE

-- Kinga | August 17, 2020

Question:

Dear sir,
I write a fiction novel, which action takes place in the past – in the year 3000 BCE, to be exact. There are some astronomical nuances that are important for the plot, therefore I would like to make them scientifically correct. One chapter is related to vernal eqiunox (spring equinox). As far as I know the exact date of this astronomical event changes in time, mostly due to precession. Right now we have it around 20th March, when the sun is in the First Point of Aries. Yet for the year 3000 BCE that obviously wasn’t the right date. I suspect it was moved more toward April but I am not certain. I tried to search for tables with dates, unfortunately they all inform about the future vernal equinoxes or about the past ones yet only back to 1000 BCE. For the date 3000 BCE I didn’t find anything. Could you help me in this matter? I would like to know the exact date of the vernal equinox for that year and the constellation in which the reference point of the vernal equinox was located on that day. I’ll be grateful for the answer, as it will make my work progress.
Thank you in advance,
Kinga

-- Kinga

Answer:

Fortunately, the JPL Horizons ephemerides calculator can provide the date and time of the vernal equinox for dates in the distant past. The vernal equinox, when the apparent RA of the Sun was zero while its apparent declination was increasing, occurred at 05:27 UT on April 15 in the year 3000 BCE. The Sun was in the constellation Taurus on this date.

-- Jeff Mangum

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