Iniciación ASTRONOMY (31) MECHANISM OF AN ECLIPSE OF MOON
Lunar eclipses are caused by interposition of the Earth between the Sun and the Moon, ie, when the Earth's shadow falls on the Moon, and occurs necessarily on a full moon. The Sun and Moon in opposition, ie, diametrically opposite in the sky with respect to the Earth as a lunar eclipse requires alignment the Sun, Earth, Moon.
If a spherical opaque body is placed before a light source also spherical, the boundary of the shadow will be the conical surface tangent to the two bodies and appear shaded areas and shadow areas. The shadow ring is substantially the same width as the Moon and the diameter of the shadow is nearly triple.
In the case of a lunar eclipse, the Sun is the light source and the Earth is opaque body. For the Moon enters the shadow cone is necessary that the Moon is in opposition and at Full Moon or Full Moon. If the whole moon enters the umbra will be a total lunar eclipse, if not enter a part, will be a partial lunar eclipse.
If the lunar orbit plane coincide with the ecliptic, in each competition or full moon, there would be a lunar eclipse. But remember that the plane of the lunar orbit is inclined 5 º 8'respecto of the Ecliptic and therefore the umbra will sometimes below and other above the moon, then there will be no eclipse of the moon. When there is an opposition and Moon encientre the node (when the moon's latitude is zero) or close to it, then there will be a lunar eclipse.
The lunar eclipse you can see all the observers who see this item on the skyline. Copper dyes are observed in a total lunar eclipse is due to the refraction of sunlight in Earth's atmosphere, casting shades on the Moon comparable to those of a setting sun lighting the moon during an eclipse depends on our atmosphere: dust, volcanic ash suspended in eclipse darkens the air.
The edge of the Moon is dark, with no significant first so then it is more noticeable. After an hour the Moon has entered fully into the penumbra of the Earth and has lost luster. See a black notch biting the edge of this, is the entry into Earth's shadow. Notch increased progressively and in an hour and has engulfed the entire lunar disk.
At first, the shadow is blue-gray and as surrounding the lunar disk becomes red. A total eclipse from dominating the red, but the tone varies in the course of the phenomenon.
Iniciación COURSE A LA ASTRONOMY (30) EXPLANATION OF PHASES LA LUNA
Over time the zone light will enchancha and spend a week since the New Moon, the Moon is 90 degrees from the sun (the moon is square) and is in Phase Waxing Crescent seeing crescent-shaped illuminated . His age is 7 days, 9 hours, 11 minutes and 0.72 seconds in this position, the moon passes the meridian of the place about 6 hours of sun
In successive days, the straight edge by increasing the illuminated curve until two weeks after New Moon or Full Moon Full Moon seeing the whole disk illuminated. His age is 14 days, 18 hours, 22 minutes and 1.45 seconds. The Moon passes the meridian at midnight and is in opposition (the Earth is situated between the Sun and the Moon). The lengths of the Sun and the Moon differ 180 degrees. The observer, located on the dark side of Earth is the night for him, you see the whole face of the moon illuminated. At Full Moon, the Moon is said to decrease.
spend a week at Full Moon, the Moon is Last Quarter, and it looks like a semicircle but the diameter to the east (right). The age of the Moon is 22 days, 3 hours, 33 minutes and 2.2 seconds. Is when the moon is 270 º of the Sun (the Moon is square again.)
Over time, the Moon will be in the form of a piece but with the horns to the right, until finally at the age of 29 days, 12 hours, 44 minutes and 2.9 seconds, limited to one synodic month, we get to the new moon that marks the beginning of another lunation.
Iniciación COURSE A LA ASTRONOMY (29) moon phases.
moon phases are called to the various aspects under which the Moon appears to depend on the relative position of the Sun, Earth and Moon, in a cyclical proceo determined by the various states of enlightenment in which shows the lunar disk. If you watch me to the moon on successive days we see their apparent shape varies from day to day.
The period of this cycle or lunation is a synodic month. To explain this phenomenon assume phase to earth at the center of a circle that represents the lunar orbit. Assuming the Sun on the right, the hemisphere of the Moon that appears to be illuminated and dark sun reversed.
The origin of the lunar cycle is in the so-called new moon or new moon, when the moon is in conjunction with the Sun at this time starts a synodic revolution. The Earth Moon presents the hemisphere not illuminated by the Sun, and is dark, therefore, we see the moon. Age is called the Moon for a given time of the lunation the time between the New Moon (age = 0) and that instant. The rising and setting of the moon and the sun almost coincide, as well as the passage of these stars over the meridian. Having the moon a proper motion journal close to 13 º in the forward direction, while the Sun moves 1 to day, the Moon moves with respect to the sun about 13 ° per day and, therefore, 2 or 3 days after new moon is submitted after the setting of the sun in the form of thin spindle, and a piece with horns to the left.
Iniciación COURSE A LA ASTRONOMY (28) Libration of the Moon.
As the orbit is ecliptic and the axis of rotation is inclined from the perpendicular to the orbital plane, there is an effect known as libration (in longitude and latitude) that we can see from our planet a little more than half of the lunar surface (59%).
The libration in longitude because the Moon rotates uniformly about its axis, while the orbital motion is faster near the perigee Maas and slower near the peak (by Kepler's second law). Therefore, a lunar surface detail, which at perigee and apogee is located right on the meridian of the place, find something to the east of the meridian when the Moon is between the perigee and apogee, and slightly to the west when it is between the apogee and perigee.
This implies that we see over 50% of the area lunar.El period of libration in longitude is equal to the anomalistic month.
The libration in latitude is due to the inclination of the lunar rotation axis perpendicular with respect to the orbital plane. The period of libration in latitude is equal draconítico month.
The night or parallactic libration depends on the place of observation on the surface of the Earth: two observers who are in two different points on the earth's surface at one time see something different regions of the lunar surface.
Iniciación COURSE A LA ASTRONOMY (27) revolutions of the moon.
The period of movement of the Moon around the Earth can be seen in different ways: 1 .-
sidereal month: it is the time between two consecutive steps of the Moon by the hour circle of a star seen from Earth. Its duration is 27 days, 7 hours, 43 minutes and 11.6 seconds. It matters little astronomy and its value is calculated as the semi-major axis of the orbit. 2 .- synodic
Month: The time elapsed between two similar positions of the Moon and the Sun, ie between two phases of the moon. Its duration is 29 days, 12 hours, 44 minutes and 2.9 seconds and deconomia lunation. 3 .- Month
tropics is the time between two consecutive steps of the Moon by the hour circle of Aries point. Its duration is 27 days, 7 hours, 43 minutes, 4.7 seconds. 4 .- anomalistic
Month: is the time between two consecutive steps of the Moon perigee. Its duration is 27 days, 13 hours, 18 minutes, 33.2 seconds. 5 .- draconítico
Month: is the time between two consecutive steps of the Moon by the ascending node of its orbit. Its duration is 27 days, 5 hours, 5 minutes, 35.8 seconds.
The moon has a rotation in the forward direction around its axis, and time spent in a rotation is the same as its sidereal revolution. The rotation length is equal to what it takes to travel its orbit around the Earth, so the Moon always presents the same face to Earth except for slight variations due to librations.
Iniciación A LA COURSE ASTRONOMY (26) .- LA LUNA LUNAR ORBIT.
For observers, before embarking on an observation of the Moon, should know its orbit around the Earth, to understand its apparent movement and the various issues that may occur in the sky to an observer on Earth.
The Moon is the astronomical object closest to the Earth. The moon rotates
long around the Earth describing an ellipse in one of whose foci is the Earth with a large tilt igual a 0,05490. Siguiendo este valor, el perigeo (distancia mínima de la Luna a la Tierra) está en 363.296 Km. y el apogeo está en 405.50, siendo la distancia media 384.400 Km. Su semieje mayor es de 384.399,1 Km, la inclinación respecto de la eclíptica es 5,14540 (fracción de grado) o 5º 08´ 43 ,33017´´ (grados sexagesimales). La longitud del nodo ascendente y la latitud del perigeo varían cíclicamente con el tiempo entre 0º y 360º, y no se les puede definir con un valor medio.
La intersección de la órbita lunar y la eclíptica determinan una recta que corta en dos puntos, denominados nodo ascendente y nodo descendente. Sólo en los puntos del nodo ascendente and down results in the phenomenon of eclipses, both lunar and solar. The line connecting two nodes is called line of nodes. This line does not conseva a fixed direction with respect to distant stars, but retrograde in reverse on the plane of the ecliptic the moon's orbital motion with a period of 18.6 years (6793.5 days). As a result, to return to the same node, you must perform at least one complete revolution (month draconícito).
The line joining the perigee and apogee is called the apsidal line. This line has a direct movement and takes place in the lunar orbit plane. Its period is 8.85 years (3232.6 days).
Iniciación COURSE A LA ASTRONOMY (25) A TOTAL ECLIPSE OF SUN
continue with the process followed by an eclipse.
suddenly appears the solar corona, appear in the sky the planets and brightest stars. The total is short and the third contact occurs in a similar manner but in reverse order.
Another type of solar eclipse is a hybrid, mixed or worn. Occurs when the tip of the umbra falls short on the surface of the Earth and the event is void, but is changing its project total to finish abort.
Mercury and Venus are the planets closest to the Sun than the Earth, are called inner planets. Proóximo
The planet Mercury and the Sun is moving in the sky faster than any other planet and its rotation period is 58.65 days, ie 2 / 3 of its period of movement around the sun is Venus
the star, following the sun and moon, the brighter the sky, reaching favorable conditions (39 days before or after inferior conjunction) the magnitude -4.4. Because that appears before sunrise or after sunset, is known as "morning star" or "star of the evening."
The maximum angular separation of Mercury is 28 ° and Venus is 47 degrees, therefore never be seen at the zenith of the sky at midnight.
Mercury always appears near the sun, you can watch 2 hours and 15 minutes, at most, before sunrise and after sunset solar. Making it difficult telescopic observation of this planet, since sunlight and prevents or hinders. Venus
also observed before sunrise or after puesta.Al be further from the Sun, is visible up to 4 hours before sunrise and after sunset solar.
Both planets show phases like the Moon. The inner planets have a different geometry of planetary positions to the outer planets. To explain these relative movements consider the sun in the center of two concentric circles, representing the lower radio inside the orbit of the planet and the largest radio to Earth orbit.
is said that a planet is at inferior conjunction when the planet is at its farthest from Earth. In the vicinity of a superior conjunction, an inner planet shows its face fully illuminated, but it is hard to see considering his apparent closeness to the Sun
Approaching greatest elongation east, being visible at dusk, the planet reveals a growing phase effect as the moon.
After a while, the planet is at inferior conjunction, it is said that the planet is at inferior conjunction when the planet is in place closest to the Earth. At inferior conjunction the planet can not be observed both for its proximity to the Sun and the small lighted portion, as directed toward Earth, its dark side. Subsequently, the planet reaches its greatest elongation west, being the planet visible in the vicinity of the dawn, until finally found a new superior conjunction.
Iniciación COURSE A LA ASTRONOMY (24) OTHER ASPECTS OF THE ECLIPSE OF THE SUN.
If the moon is at an angular distance less than 15 ° 21 of the node will be a partial solar eclipse this type of eclipse the moon does not touch anywhere on the Earth's surface and occurs at high latitudes (North or south). All partial eclipse takes place in two contacts. The first contact is the moment of contact between the solar and lunar discs, marking the beginning of the phenomenon. Following the progress of the moon, we reached the middle of the eclipse, which motion covers a larger fraction of the solar disk. From this point the Moon begins to leave until the last contact, the end of partial eclipse.
If the new moon is between 9 º 11 º 50'y 55'del node, the umbra will reach the Earth, resulting in an annular solar eclipse, the moon is here at the apogee and the Earth at perihelion, then the umbra is remains at 39,400 km, the center of the Earth and creates a negative or antiumbra umbra. Image of the Moon appears smaller than the Sun showing silhouettes on the bright solar photosphere. This type of eclipse has four contacts. There is a partial phase which will produce the first contact, or moment that you first touch both discs. Gradually, for an hour and a half, the solar disk will hide until the second contact occurs: when the lunar disk completely enters the solar surface. Starts central or annular phase, culminating in the middle of the event. Subsequently reversed with a third contact processes or end of the fourth annular contact or view the eclipse. Outside the annular area the observer located in the shadows, sees the phenomenon as partial. When
the new moon is less than 9 ° 55'del node and the perigee, while the Earth at aphelion, the umbra intersects the Earth producing a total solar eclipse shadow cones produce a sweep on the surface Earth called path of totality, from which the phenomenon is seen as total, out of the umbra the event is seen as partial. Total eclipses have four contacts. In the first contact both discs are played but before reaching the second contact, the ambient light changes dramatically and atmospheric parameters change. At the instant of second contact occurs diamond ring, a glow that the effect of radiation is place at the point where the photosphere disappears.
Iniciación COURSE A LA ASTRONOMY (23) retrogradation.
Thanks to the laws of Kepler solved the problem of the curious movement of the planets called retrogradation.
By observing the motion of a planet in the sky, is moving from West to East. However, the movement stops and often reverses the planet in an east-west, so that retraces path of the movement to stop this movement and then resume it at a West-East. This is a perspective effect due to the relative positions of the Earth and the planets on the starry background. Mechanism
a solar eclipse: One of the biggest matches of Nature: the Sun and Moon appear in the sky with the same apparent size as seen from Earth. The Moon has a diameter of 3,475 km is 400 times smaller than the Sun (1.392 million km), indicating that it is 400 times away. This condition allows the moon to cover the solar disk producing the total solar eclipse taking place for solar eclipses must be an alignment is in order, Sun-Moon-Earth, which happens every month at new moon if plans for lunar and terrestrial orbits coincide, but as the moon's orbit is inclined 5 degrees from to the ecliptic and is located sometimes above and other below the plane. Both planes, ecliptic and lunar, intersect at two points, called nodes, which are not fixed, and the moon passes twice a month. These points are the only ones that can produce eclipses.
during the solar eclipse, the moon casts a shadow on the earth's surface. These shades are composed of two distinct areas, the penumbra or outer shadow and inner shadow or umbra.
Iniciación COURSE A LA ASTRONOMY (22) consequences of the laws of Kepler.
According to 1 st Law, as the planets orbit the Sun ellipses and meet in one focus, distance the planet from the Sun varies, with the minimum distance when the planet is at perihelion and the maximum distance when the planet and is in line afelio.La ranging from perihelion to aphelion is called the apsidal line.
ellipses of the planets have low eccentricity (maximum 0.247 for Pluto), ie, their orbits are almost circulares.Los planets orbits travel in the forward direction (counter-clockwise to an observer in the northern hemisphere).
According to the 2 nd Law, the speed of the planet is not uniform, being greater at perihelion than at aphelion, as the distance from the Sun in the first minor in the second. Ie, "that in time equal, the ellipse arcs are traversed by a planet, the greater the closer the planet is the sun. "This difference in speed, and later was shown by Newton, is due to the attraction of the mass of the Sun exerts on the mass the planet, which being the planet next to the sun increases the attractiveness and its speed is greater.
According to the 3 rd Law, it follows that the average speed with which roam the orbits of the planets is much smaller, the farther apart the Sun's planets
Kepler's three laws, also marks the orbits of satellites around their planets.
