Sidereal Time and Hour angle (english version)


Sidereal time When talking about times or periods in astronomy, and added the sidereal qualifier is to be noted that the benchmark
is the sky, the stars. The word “sidereal” comes from the Greek
“Iron” (σίδερο=Sidero) and applies to the stars because
the meteorites fallen from the sky had a large quantity of this metal, and
old attributed the iron to stars. Well, the sidereal time is the time measured
by movement of the Vernal Point (or Aries Point) on a place on the surface of the Earth The Vernal Point (0 degrees Aries) is the point of
intersection between Celestial Equator and the
ecliptic plane. This point is also known as Spring Equinox and is one of the two equinoctial points. the other is its opposite, Libra point, or autumn
equinox. This point is not really fixed, because it retrograde
52 seconds per year, due to the movement of precession
of the equinoxes. but for purposes of the sidereal time measurement
is a good benchmark. When the Vernal Equinox cuts the local meridian,
the sidereal time is 0 hours 0 minutes. in this moment begins the sidereal day. the sidereal day does not last 24 hours, as the solar day,
but is slightly shorter. 23 hours and 56 minutes. This means that every sidereal day is about 4 minutes
shorter than the solar day. why is this way? Consider an observer somewhere.
Look at the meridian of that place. Remember what is the meridian Is a plane that intersecting the vertical, passes
both by the north and south cardinal points. This plan helps us to know when it is noon,
because the Sun cut the meridian at this moment. The observer is located in the Northern Hemisphere
and he look toward the South. to measure a solar day, we count the time it takes
the sun to pass twice by that meridian and this period we established by convention that are
24 hours but the Sun is much closer to us than the
stars so the difference is that when the Earth shifts
in orbit the sun has moved from the previous day near
a degree in the sky to observer’s left, that is towards the
West. So, when the reference star, or Vernal Point,
culminate that is, when passing through the local meridian, the sun has not yet reached the culmination, and indeed
still need about 4 minutes to do. The Sidereal time, then, is the distance in hours,
minutes and seconds of the Vernal Point to local meridian. When this point culminates in the local meridian,
the sidereal time is 0 hours 0 minutes,
as we have said already. The Hour Angle (H) is the distance in hours,
minutes and seconds between a star and the local meridian When the Hour Angle is 0 hours 0 minutes
the star culminate on the meridian that is, at the upper meridian. Fundamental equation in astronomy of position. The fundamental relationship in astronomy of position
is this: Local Sidereal Time (LST) is equal to local hour angle (LHA)
+ Right Ascension (RA) of an object. That is, if we add the Right Ascension (RA) of a
star, to Local Hour Angle (LHA) that always depend on our meridian
local always will result in our Local Sidereal Time (LST).

20 thoughts on “Sidereal Time and Hour angle (english version)

  1. Error at 4:14: "Sun appears to move 1° towards the west each day." Not so. The Sun's apparent motion around the ecliptic over the course of a year (360°/365 days = just under 1° per day) is EASTward, not westward. Also, it is "towards the left" (ant-clockwise) only for northern hemisphere dwellers. For observers in the southern hemisphere it is to the right (clockwise).

  2. It's true, is a transcription error and after reading. The Sun, Moon, planets (when moving forward) move each day a little to the east, and from the point of view of an observer in the northern hemisphere, south-facing, move to your left.

    I appreciate the comment, I will correct ASAP in the video.

    Thanks and regards!!!

  3. hey wat if the earth is shifted due to magnetic of nibiru and the north pole is now Herne Bay and the axis is pretty much upright whether that effects or not i dont know. how does this effect transit currently

  4. i have seen astronomical programs with infered that clearly showed an unidentified object the moon has been rotating off axis for the past week and ive seen photos of nibiru along with the planets of orbit heres a link /watch?feature=player_embedded&v=t-xYzGdWJq0 can u please answer my question now? the earths magnetic field causes it to shift from the overpowering by nibiru were on 51 degrees shift London England is the north pole

  5. It is easy to answer your questions: go outside and projected the sun with binoculars on a daughter of paper. If you see a second sun, then you will be right and there will be Nibiru. If you do not see, is that this elusive planet there. Do the tests yourself, observe yourself.

  6. so is there any computer program that can show me a coordinates so that i can check the planetary transit with real time. once again Herne Bay is the north pole and the poles are almost straight up but its varies because this huge mass Nibiru is causing all these magnetic changes

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