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March equinox
The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (or spring equinox) in the Northern Hemisphere and as the autumnal equinox (or fall equinox) in the Southern Hemisphere.
On the Gregorian calendar at 0° longitude, the northward equinox usually occurs on March 20. However, it can occur as early as March 19 (which happened most recently in 1796, and will happen next in 2044), and it can occur as late as March 21 (which happened most recently in 2007, and will happen next in 2102). For a common year the computed time slippage is about 5 hours 49 minutes later than the previous year, and for a leap year about 18 hours 11 minutes earlier than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from March 20 each year.
The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere but marks the beginning of astronomical autumn and the end of astronomical summer in the Southern Hemisphere.
In astronomy, the March equinox is the zero point of sidereal time and, consequently, the right ascension and ecliptic longitude. It also serves as a reference for calendars and celebrations in many cultures and religions.
The point where the Sun crosses the celestial equator northwards is called the First Point of Aries. However, due to the precession of the equinoxes, this point is no longer in the constellation Aries, but rather in Pisces. By the year 2600 it will be in Aquarius. The Earth's axis causes the First Point of Aries to travel westwards across the sky at a rate of roughly one degree every 72 years. Based on the modern constellation boundaries, the northward equinox passed from Taurus into Aries in the year −1865 (1866 BC), passed into Pisces in the year −67 (68 BC), will pass into Aquarius in the year 2597, and will pass into Capricornus in the year 4312. It passed by (but not into) a 'corner' of Cetus at 0°10′ distance in the year 1489.[citation needed]
In its apparent motion on the day of an equinox, the Sun's disk crosses the Earth's horizon directly to the east at sunrise; and again, some 12 hours later, directly to the west at sunset. The March equinox, like all equinoxes, is characterized by having an almost exactly equal amount of daylight and night across most latitudes on Earth.
The Persian calendar begins each year at the northward equinox, observationally determined at Tehran.
The Indian national calendar starts the year on the day next to the vernal equinox on March 22 (March 21 during leap years) with a 30-day month (31 days in leap years), then has 5 months of 31 days followed by 6 months of 30 days.
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March equinox AI simulator
(@March equinox_simulator)
March equinox
The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (or spring equinox) in the Northern Hemisphere and as the autumnal equinox (or fall equinox) in the Southern Hemisphere.
On the Gregorian calendar at 0° longitude, the northward equinox usually occurs on March 20. However, it can occur as early as March 19 (which happened most recently in 1796, and will happen next in 2044), and it can occur as late as March 21 (which happened most recently in 2007, and will happen next in 2102). For a common year the computed time slippage is about 5 hours 49 minutes later than the previous year, and for a leap year about 18 hours 11 minutes earlier than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from March 20 each year.
The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere but marks the beginning of astronomical autumn and the end of astronomical summer in the Southern Hemisphere.
In astronomy, the March equinox is the zero point of sidereal time and, consequently, the right ascension and ecliptic longitude. It also serves as a reference for calendars and celebrations in many cultures and religions.
The point where the Sun crosses the celestial equator northwards is called the First Point of Aries. However, due to the precession of the equinoxes, this point is no longer in the constellation Aries, but rather in Pisces. By the year 2600 it will be in Aquarius. The Earth's axis causes the First Point of Aries to travel westwards across the sky at a rate of roughly one degree every 72 years. Based on the modern constellation boundaries, the northward equinox passed from Taurus into Aries in the year −1865 (1866 BC), passed into Pisces in the year −67 (68 BC), will pass into Aquarius in the year 2597, and will pass into Capricornus in the year 4312. It passed by (but not into) a 'corner' of Cetus at 0°10′ distance in the year 1489.[citation needed]
In its apparent motion on the day of an equinox, the Sun's disk crosses the Earth's horizon directly to the east at sunrise; and again, some 12 hours later, directly to the west at sunset. The March equinox, like all equinoxes, is characterized by having an almost exactly equal amount of daylight and night across most latitudes on Earth.
The Persian calendar begins each year at the northward equinox, observationally determined at Tehran.
The Indian national calendar starts the year on the day next to the vernal equinox on March 22 (March 21 during leap years) with a 30-day month (31 days in leap years), then has 5 months of 31 days followed by 6 months of 30 days.