Dear Fritz, Using Find Annual Feature function (sdxFindAnnFeatx)of the The SUN API www.sunlitdesign.com/products/thesunapi I get the follwing value for the solstice this December:
December 21 19:21:30.7143 [UT] (which is +/- 10 seconds of the true value) Compare with http://aa.usno.navy.mil/data/docs/EarthSeasons.html which shows the value to the nearest minute. Using the Declination function (sdxDecl) we find the declination for this time on the 20th, 21st and 22nd: 20th -23:26:06.7694 21st -23:26:20.9605 SOLSTICE 22nd -23:26:06.8546 Which have the following differences from the Solstice 20th -0:00:14.1911 21st 0 SOLSTICE 22nd -0:00:14.1060 David www.sunlitdesign.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fritz Stumpges Sent: Thursday, 20 December 2001 9:12 AM To: 'Frank Evans'; [email protected] Subject: RE: Query about solstices This topic got me wanting to get a piece of pipe and try it! >From my new Sky software, which I'm just getting to know, I found that solstice is at about 11:22 on the 21st. I then got the declinations on the day before and after at this time. But the sun changes only 14 seconds(arc)/day. This means that on the 20th it is -23deg26m14s and on the solstice it is -23deg26m28s. How does this compare with other sources for accuracy? Anyway, at this required resolution, it would take a "pipe" or earthen hole, 307 feet long, assuming a "pinhole" or? which could be resolved as 1/4 of an inch of movement (@307 ft!) This is to measure the actual movement that day with respect to the day before and day after. Is this correct? And if so, I doubt they really could resolve this. This is 130 times smaller than the apparent diameter of the sun!? What do you all think? There goes the fun I was going to have with this endeavor tomorrow. I'll be there celebrating this magical moment anyway, as I'm sure many of you will!!!! Cheers, Fritz -----Original Message----- From: Frank Evans [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 19, 2001 11:46 AM To: [email protected] Subject: Query about solstices Greetings fellow dialists, You don't have to have a clear sky on the actual day you are wishing to mark sunrise or sunset. Martin Brennan in his book "The Stones of Time" showed elegantly how the people at Newgrange in Ireland did it five thousand years ago with the rising solsticial sun shining down a long shaft into the immense earthwork onto auxiliary marks for adjacent days. More recently there is a simple noon line in Durham Cathedral dated 1829 with extra marks for five and ten minutes after noon. This line was simply a clock regulator, though. Frank, 55N 1W -- Frank Evans
