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Thread: Spring Equinox 2019 Question

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    Default Spring Equinox 2019 Question



    Online sources give March 20 at 17:58 EST as the date and time for the Spring Equinox. I am located 10 degrees west of 75 degrees West, ESTís central meridian, but Iím still in the EST time zone. Fiddling around with Heavens Above, I find that the sunís RA does not reach precisely 0h and its DEC does not reach precisely 0 degrees until March 21 at 12:14:30 AM. Why the 4+ hour delay? I would have expected those values at or near March 20 at 17:58 EST....more likely at 18:38 EST to account for my offset from the central meridian. Heavens Above knows my location (Chattanooga). Iím just trying to understand these numbers.

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    Default Re: Spring Equinox 2019 Question

    Initially don't know, because I'm unsure of all the entry parameters you used. But what you can do is go onto Calsky.com and do the same procedure you did on Heavens Above and see if you get the same answer.

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    Default Re: Spring Equinox 2019 Question

    I tried it again with Calsky and got minimal values for solar RA and DEC at 17:27 EST on March 20....much closer to the reported value of 17:58 EST. I suppose there are compromises in the various algorithms being used by Heavens Above and Calsky. Still, Heavens Above seems pretty far off the mark. Thanks for directing me to Calsky.
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