Talk:September equinox
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Equinox on September 21
editThis equinox will occur on September 21, 2096 in UTC and so the changre just made by an anonymous editor is justified. Karl (talk) 12:08, 20 August 2014 (UTC)
2015 sep Equinox: 2015-Sep-23 08:20:33.876
editIt is very difficult to find the exact times of solstices and equinoxes, to better than a minute of resolution -- and therefore hard to resolve discrepancies in various sources.
- stellafane.org/misc/equinox.html
- This source has a handy any-year calculator that gives
- TDT = Wed, 23 Sep 2015 08:21:33 GMT
- UTC = Wed, 23 Sep 2015 08:20:06 GMT
- but the footnotes explain that these times are only approximate, to about a minute of accuracy (and the following shows them to be about a half-min off).
- www.survival.org.au/solstice2013.php
- This is the best discussion of how hard it is to obtain exact times, and how to get them from an online NASA calculator:
- ssd.jpl.nasa.gov/horizons.cgi
Ephemeris Type [change] : OBSERVER Target Body [change] : Sun [Sol] [10] Observer Location [change] : Geocentric [500] Time Span [change] : Start=2015-09-23 08:20:30, Stop=2015-09-23 08:20:40, Intervals=20 Table Settings [change] : QUANTITIES=30,31 Display/Output [change] : default (formatted HTML) 2015-Sep-23 08:20:33.000 68.182392 179.9999901 0.0002366 2015-Sep-23 08:20:33.500 68.182392 179.9999957 0.0002366 2015-Sep-23 08:20:34.000 68.182392 180.0000014 0.0002366 2015-Sep-23 08:20:34.500 68.182392 180.0000071 0.0002366 Date__(UT)__HR:MN:SC.fff CT-UT ObsEcLon ObsEcLat
Which leads to:
2015-Sep-23 08:20:32.876 68.182392 179.9999887 0.0002366 2015-Sep-23 08:20:33.876 68.182392 180.0000000 0.0002366 2015-Sep-23 08:20:34.876 68.182392 180.0000113 0.0002366 The dynamical Coordinate Time scale is used internally. It is equivalent to the current IAU definition of "TDB".
Giving a final result of:
- 2015-Sep-23 08:20:33.876 UTC (+68.182392 = CT/TDB)
In conclusion, 8:20:34 and 8:21 UTC is the proper rounded time, 8:20 is understandable -- but 8:22 seems somewhat wrong, for any general usage.-96.233.20.34 (talk) 21:37, 21 September 2015 (UTC)
- Hi. I like your comment, but most of us would really appreciate an updated time for the equinox. In my view, this should be prominently displayed, and should be easy to update automatically. Curiousdale (talk) 16:57, 22 September 2023 (UTC)
more precise Solstice and Equinox times
editThe English speaking world seems to be limited to approximate Solstice and Equinox times, to about the nearest minute.
The French offer a more precise, to the second, master table:
- fr.wikipedia.org/wiki/Mod%C3%A8le:Solstice-%C3%A9quinoxe
2013 20 11:01:55 21 05:03:57 22 20:44:08 21 17:11:00 2014 20 16:57:05 21 10:51:14 23 02:29:05 21 23:03:01 2015 20 22:45:09 21 16:37:55 23 08:20:33 22 04:47:57 2016 20 04:30:11 20 22:34:11 22 14:21:07 21 10:44:10 2017 20 10:28:38 21 04:24:09 22 20:01:48 21 16:27:57 2018 20 16:15:27 21 10:07:18 23 01:54:05 21 22:22:44 Références : mars • juin • sept. • déc. Institut de mécanique céleste et de calcul des éphémérides
Most WP readers do not care about this -- but some might like access to the more accurate times. How can we provide such access in a good way? Would we ever want to replace our template master table with a more-precise master table of times? -71.174.188.32 (talk) 19:14, 22 December 2015 (UTC)
Chart
editThe chart is extremely hard to read. It's just a bunch of numbers all clumped together. Maybe if there are four different background shadings (one to distinguish the two columns for March; one to distinguish the two columns for June; September; December; etc.), that would make the chart easier to read. Thoughts? Thanks. Joseph A. Spadaro (talk) 19:34, 22 September 2016 (UTC)