On 12/19/2010 05:01 PM, Mauro Lacy wrote: > On 12/19/2010 04:44 PM, Mauro Lacy wrote: >> On 12/19/2010 01:28 PM, Mauro Lacy wrote: >>> Here's an open version of the same database: >>> http://www.hermit.org/Eclipse/when_search.shtml >>> I've downloaded the raw file, and after searching for total lunar >>> eclipses from Dec 19 to Dec 23, post Oct 15 1582(before that, Julian >>> dates are used), I've found the following "solstice eclipse" candidates: >>> >>> 1638|12|21|01:59|L|T|N-|119||-0.139|2.632|1.605|12960|5760||| >>> 1703|12|23|06:30|L|T|S-|120||0.025|2.891|1.763|14160|6360||| >>> 1768|12|23|15:07|L|T|S-|121||0.060|2.770|1.757|12840|6000||| >>> 1945|12|19|02:20|L|T||124||-0.284|2.355|1.348|12360|4800||| >>> 1964|12|19|02:37|L|T||134||0.380|2.171|1.180|11760|3600||| >>> 2010|12|21|08:17|L|T||125||0.321|2.306|1.261|12600|4440||| >> Wolfram Alpha gives solstice dates for each year easily. According to >> wolframalpha, the (northern hemisphere) winter solstice for the year >> 1703 occurred Saturday, December 23, 7:04 am LMT. >> http://www.wolframalpha.com/input/?i=1703+northern+hemisphere+winter+solstice+date >> >> LMT stands for Local Mean Time(an old form of timezone, it seems), >> because wolfram alpha likes to give local times, based on the location >> of the questioner. Searching on how to convert from LMT to GMT(UT), for >> western latitudes you have to add the local latitude in degrees divided >> by 15 degrees. So, 7:04 am LMT in my latitude is around 11:04 am GMT. >> >> The last time an eclipse coincided with a (northern hemisphere winter) >> solstice, then, was December 23, 1703. Not that this is important, of >> course, but is in the name of precision, and of course, of being picky. > In the name of precision (and of being picky) that is wrong. I misread > the date of the solstice, which is December 22, not 23. This is off then > by around 20 hours. > So, neither of those dates coincide with a solstice inside the 24 hours > range, and the closer one is December 21, 1638. >> According to the same, the winter solstice date for 1638 was 12:20 pm >> LMT, Tuesday, December 21. That date is around 16 pm GMT for my >> latitude, so the lunar eclipse of that day is out of the 24 hours rule >> established before(by a margin of about 2 hours), even when it happened >> on the same calendar day. >> >> Calculating the precise solstice time for the year 1554 is left as an >> exercise for the picky.
Above I meant longitude, not latitude, or course. Using wolfram alpha again(which is a wonderful tool), I've got the following for 1554: http://www.wolframalpha.com/input/?i=december+1554+lunar+eclipse A partial lunar eclipse on 9:38 pm LMT, December 8, 1554, Julian calendar. The solstice that year occurs on: http://www.wolframalpha.com/input/?i=1554+northern+hemisphere+winter+solstice Wednesday, December 12, 1554, Julian calendar. There's a relatively close match that year, but the eclipse is partial, and the difference is 4 days It seems that a difference of +/- 12 hours is too narrow. Not even tomorrow's eclipse qualify to that. I'll now look for coincidences in the 24 hour range(+/- 24 hours) to finally settle how rare is tomorrow's eclipse.
