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mreq
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Hy.
Why some months have 30 and some 31 days , and february 28?
Thanks!
Why some months have 30 and some 31 days , and february 28?
Thanks!
Last edited:
http://www.infoplease.com/ipa/A0002061.htmlWhen Rome emerged as a world power, the difficulties of making a calendar were well known, but the Romans complicated their lives because of their superstition that even numbers were unlucky. Hence their months were 29 or 31 days long, with the exception of February, which had 28 days. However, four months of 31 days, seven months of 29 days, and one month of 28 days added up to only 355 days. Therefore the Romans invented an extra month called Mercedonius of 22 or 23 days. It was added every second year.
mreq said:What i want to know it's if there is a connection between sun position and the number of the day? Let's say 1 june 2000, 1 june 2001, 1 june 2002, 1 june 2003 etc.
If the sun coordinates are the same.
Interesting, I had never heard that. I wonder how astronomy software deals with that? I would suspect they ignore such historical issues and just apply the modern calendar backwards.Janus said:The previous calendar, the Julian, did not have this slight correction, so when Britain and the American colonies switched to the Gregorian calendar in 1751, it was 11 days out of sync with the Sun. As a result of the switch, Sept 2 was followed by Sept 14 to re-align the date and Sun.
russ_watters said:As Janus said, close but not exact. How exact do you want to get? Interesting, I had never heard that. I wonder how astronomy software deals with that? I would suspect they ignore such historical issues and just apply the modern calendar backwards.
russ_watters said:Heh, duh, I should have realized how easily I could test that!
[...and Starry Night works the same way.]
russ_watters said:Agreed. But if any unscrupulous high school students read this thread, they may go start arguing with their teachers about what date certain historical events happened on. Magna Carta? June 15, 1215? Naah.
Maybe/mabye not. When I bought Starry Night my primary scope was by one manufacturer and now I have a new one with a label that belies the fact that the OTA and mount are repackaged products from still two more manufacturers! So I've got a lot of major labels covered!KalamMekhar said:I bet I can guess who manufactures your telescope. Hahahaha
Isn't that the point? What does it really mean to say that the Magna Carta was signed on June 15, 1215? According to the people who signed it? According to our new calendar scrolled backwards? And don't even get me started on Christmas. It is bad enough that it isn't known when exactly Jesus was born, but why was December 25th chosen? According to the Wiki it may be because that was the date of the winter solstice in the Roman calendar. But if that's the case, that means calendar changes have moved Christmas so that it is now 4 days later.Janus said:Well, not that early, as the Gregorian calendar was not introduced until 1582.
KalamMekhar said:I think it would be pretty funny if it had "this date does not exist" or something of the sort.
mreq, you have another thread open where people suggested software to you! Try it!mreq said:Hmm...
So there isn't a fixed point ?
P.S. Are this things possible with some software ? Which one ?
On Jan 15, 1540 at noon, from the earth, the sun is at:mreq said:If i take a date let's say 15th january 1540. What was the Earth position on the orbit (regarding the sun) that day, and now in 2010 when the Earth is in the same position ?
Janus said:The Tropical year, which the calendar is based upon, goes from equinox to equinox (fall to fall or spring to spring). The equinoxes, are when the tilt of the Earth is neither towards or away from the Sun, and the Sun passes directly overhead on the Equator. They corresponds with the days where we get 12hrs of light and 12 hrs of dark. Generally the spring equinox signals the start of the tropical year. (In earlier times, the calendar year also started around this time, on April first. After it was switched to January 1st, to be close to the Winter Solstice, some people mistakenly continued to celebrate the new year on April 1st. They were derisively called "April Fools", and thus was born the tradition of April's Fools Day.)
So the Earth's position is generally measured from the spring equinox.
mreq said:So the position on the orbit is not the same the next year ?
mreq said:I want to know how that point on the orbit it's calculated.
Because i set the time to june 10th 1564 (location randomly) and the sun it's in taurus constelation.
Thanks!
mreq said:Skyglobe seems to be old!
Isn't there any software to be truly profesional ? What's so hard ? (i mean like there is movie editor - which do everything ...it should be a astronomy software...)