if the GHA of Aries is 301° degrees 17.6 mins. and the GHA of star is 126 deg 27.8min, find the SHA of the star. explain the GHA of a star and SHA
To find the SHA (Sidereal Hour Angle) of a star, we need to subtract the GHA (Greenwich Hour Angle) of Aries from the GHA of the star.
The GHA represents the angular distance between the observer's position (Greenwich, in this case) and the celestial body, measured along the celestial equator. It is measured in degrees and minutes, with 360 degrees representing a full circle of 24 hours.
Given:
GHA of Aries = 301° 17.6 mins
GHA of star = 126° 27.8 mins
To find the SHA of the star, we subtract the GHA of Aries from the GHA of the star:
SHA of star = GHA of star - GHA of Aries
First, we need to convert the minutes to decimal format for easier calculation:
GHA of Aries = 301° + (17.6 / 60) = 301.2933°
GHA of star = 126° + (27.8 / 60) = 126.4633°
Now, subtract the GHA of Aries from the GHA of the star:
SHA of star = 126.4633° - 301.2933°
To simplify the calculation, we can convert the degrees to positive values:
SHA of star = (360° + 126.4633°) - 301.2933°
SHA of star = 126.4633° - 301.2933° + 360°
SHA of star = 185.1699°
Therefore, the SHA of the star is approximately 185.17°.
The SHA represents the angular distance of a celestial body from the observer's meridian, measured along the celestial equator. It is analogous to the longitude on Earth, but for celestial objects. The SHA is measured in degrees and provides a reference point for celestial navigation calculations.