Velocity correction´ formula for the rotation of the Earth

In summary, the conversation discusses the velocity correction formula for Earth when observing the Sun and measuring spectral lines. It is mentioned that the formula includes both the rotational velocity components of the Sun and the Earth's orbit, and that neglecting the Sun's rotation could result in an inaccurate calculation. It is also noted that Earth's orbit is eccentric, leading to additional radial velocities. The conversation also briefly mentions the calculation of solar wind contribution in the line of sight, with a typical value of 400 km/s.
  • #1
Ennio
26
2
TL;DR Summary
Does the velocity correction´s formula for rotation of the Earth include Sun contributes?
Let´s suppose we are observing the sun and measuring some spectral lines.

Does the velocity correction´s formula for the Earth include the rotational velocity components of the Sun as well?
or rather
are we basically measuring both velocity contributes of Earth and of Sun together (receeding or approachning depending of course from the angles) ?

v= 0.464 * sin(H) * cos(D) * cos (L) [Km/sec]

0.464 Km/sec is the equatorial radial velocity of Earth
H: hour angle of the Sun [deg]
D: declination of the Sun [deg]
P: Earth latitude of the observatory [deg]

Thanks in advance for your support
 
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  • #2
Run rotation speed at equator is about 2 km/s while Earth is only 0.46 km/s. Neglecting contribution of Sun` rotation would be a bad calculation, unless you averaging flux across whole disc of Sun. Also, Earth orbit is eccentric, which produce up to 0.5 km/s radial velocities with period of one year.
 
  • #3
trurle said:
Run rotation speed at equator is about 2 km/s while Earth is only 0.46 km/s. Neglecting contribution of Sun` rotation would be a bad calculation, unless you averaging flux across whole disc of Sun. Also, Earth orbit is eccentric, which produce up to 0.5 km/s radial velocities with period of one year.

Hi @trurle, thank you very much. Do you know how to calculate the solar wind contribution in the line of sight? I have read it is 400Km/sec
 
  • #4
Ennio said:
Hi @trurle, thank you very much. Do you know how to calculate the solar wind contribution in the line of sight? I have read it is 400Km/sec
Just multiply by cosine between wind direction (outward) and line of sight. 400 km/s is typical for vicinity of Earth indeed.
 

FAQ: Velocity correction´ formula for the rotation of the Earth

What is the "Velocity correction" formula for the rotation of the Earth?

The "Velocity correction" formula for the rotation of the Earth is a mathematical equation used to correct for the slight variations in the Earth's rotational speed. It takes into account factors such as the Earth's elliptical orbit and gravitational pull from other celestial bodies.

Why is it necessary to have a velocity correction formula for the rotation of the Earth?

The Earth's rotation is not constant due to various external forces acting upon it. This can lead to discrepancies in timekeeping and navigation systems, so the velocity correction formula is necessary to accurately measure and predict the Earth's rotation.

How is the velocity correction formula calculated?

The velocity correction formula takes into account the Earth's angular velocity, the Earth's position in its orbit, and the gravitational forces from other celestial bodies. It is a complex mathematical equation that is constantly being refined and updated as new data is collected.

What is the impact of the velocity correction formula on everyday life?

The velocity correction formula has a significant impact on everyday life, particularly in fields such as navigation, astronomy, and timekeeping. It allows for more accurate measurements and predictions of the Earth's rotation, which is crucial for many modern technologies and systems.

Are there any limitations to the velocity correction formula for the rotation of the Earth?

While the velocity correction formula is constantly being improved, it is not perfect and has some limitations. Factors such as changes in the Earth's rotation due to climate change and seismic activity can still affect the accuracy of the formula. Additionally, the formula may need to be adjusted as new data and technologies become available.

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