General
Equation of Time
|
Equation of the Equinoxes
- the right ascension of the mean equinox referred to the true equator and equinox
- alternatively, the difference between apparent sidereal time and mean sidereal time
- (GAST−GMST)
- distance between the CIO (Celestial Intermediate Origin) and the equinox along the intermediate equator
- it is the CIO right ascension of the equinox
- alternatively, the difference between the Earth Rotation Angle and Greenwich apparent sidereal time (ERA−GAST)
- Proposed by George Vernon Hudson in 1895 and first implemented by Germany and Austria-Hungary 30 April 1916
- Hawaii (always sunny) and Arizona (want less sun to conserve energy) only two states that don’t
- Daylight Saving Time (United States) 2014 began at 2:00 AM on Sunday, March 9 and ends at 2:00 AM on Sunday, November 2
Winter Time
- Practice of shifting clock back during winter months
- Opposite of daylight savings time
- Has only been applied in Czechoslovakia (gov ordinance no. 213/1946 Sb.)
- From December 1946 (3:00à2:00) to February 1947 (2:00à3:00)
- Reason: power plants had approx. 10% lack of capacity in peak hours, winter time should spread out load
- Still in laws of the Czech Republic and Slovak Republic (Slovakia)
- Line on Earth located at 180˚ longitude
- position of the International Date Line has changed several times
- Until 1845, the Philippines were on the eastern side of it (same side as the United States)
- On the eastern side of the line because it was a Spanish colony and most Europeans arrived there via the Spanish colonies in South America
- Indonesia was a Dutch colony and most European arrivals came via the Cape of Good Hope
- Indonesia was to the west of the International Date Line
- After independence of the South American countries, most people traveling to Philippines also came by way of Cape of Good Hope; decided to change from east of the line to west of the line
- Alaska, originally claimed by Russia, was to the west of the International Date Line because most travelers arrived there by way of Siberia
- United States bought Alaska in 1867 the line was moved to the west of it
- The position given on most maps is the line drawn by the British Admiralty in 1921
- 1995, Kiribati moved the International Date Line so that entire country is on the western side
- Line is as far east as 150°, farther east than Honolulu
- Because of eastern bulge in the International Date Line, Kiribati claimed that Caroline Island (10° 0' S 150° 15' W) would be the first point of land where the Sun would rise
- However, the Sun does not rise here until about 5:45 AM January 1, local time (15:45 December 31 UT), about 30 minutes after it rises in the first place in the Antarctic
- Caroline Island is in tropical sea and is not more accessible than Antarctica.
- Caroline Island is actually an atoll of 22 small islets stretched over 11 km protected by a very shallow reef, reachable by only shallow draft boat or seaplane.
- Sun rises at South East Point on Christmas Island, most south-easterly of the inhabited islands in Kiribati, at about 6:30 AM January 1, local time (16:30 December 31 UT).
- Sunrise at Pitt Island in the Chatham Islands of New Zealand occurs about 25 minutes earlier.
- Most recent change in the line was at midnight on the beginning of 2011 Dec. 31 (local time) when Samoa moved from the eastern to the western side of the International Date Line
- There was no Friday, December 31, 2011 in Samoa.
- change was made by a government with local interests
- Last place where the Sun will set December 31, local time
- For those who are nostalgic and prefer looking back on past accomplishments rather than forward towards the unknown future, the place to be is Falealupo, Samoa (13° 25' S 172° 45' W) where the Sun does not set until about 7:00 PM December 31, local time (06:00 January 1 UT).