Calculating Angle Between Ecliptic and Horizon for Observer at 18 Degrees North

In summary, the conversation discusses how to calculate the angle between the ecliptic and the horizon for an observer at 18 degrees north when the point of Aries is hiding. The solution involves using a diagram to visualize the intersection of the ecliptic and equatorial planes and drawing lines to create triangles and angles.
  • #1
Frank Einstein
170
1

Homework Statement



Which is the angle between the ecliptic and the horizon in the moment that the point of Aries is hiding for an observer whose position is 18 degrees north?

2. Homework Equations

None

The Attempt at a Solution



The first thing I have tried to is to do a drawing of the situation: here it is: http://postimg.org/image/dh3xkvipv/

Then I went to the software stellarium and I put the observer exactly at 18 degrees north; found a star with zero right ascension and I went forward in time until the star had height zero; then, I measured the difference between the north and the ecliptic and I got about 84 degrees: http://postimg.org/image/vs1i12dwp/.

If I calculate 90-23.5+18 I get 84.5, which is similat to the 84 that I got with the aproximate calculus at stellarium, but I don't know how to justify it.

Can anyone thell me if there is a way to calculate the angle between the ecliptic and the horizon in the moment that the point of Aries is hiding for an observer whose position is known?

Thanks for reading.
 
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  • #2
I think if you make a sketch where you're looking edge-on at the intersection of the ecliptic and equatorial planes (so the planes appear as two crossed lines and you the observer are looking on from the first point of Aries), and you center their intersection in the center of a circle representing the Earth in profile, then you should be able to convince yourself that Aries first "hides" for all points on the circle to the right of the N-S line of the Earth.
 
  • #3
I agree with you; I have made that with stellarium, is the second link; what I don't know is how to prove that the angle between the horizon and the ecliptic is 84.5 degrees
 
  • #4
If, on the same diagram, you draw in the line of latitude for 18° it will be a line parallel to the line representing the equatorial plane. Draw a line from the center of the Earth circle to where that latitude line intersects the circle, and construct a perpendicular to that line there (it will be tangent to the circle). See any angles and triangles that might be of use?
 
  • Like
Likes Frank Einstein
  • #5
Yeah, I will try with that, thank you very much.
 

1. What is spherical astronomy?

Spherical astronomy is a branch of astronomy that deals with the study of celestial objects and phenomena as seen from the surface of a sphere, such as the Earth. It involves understanding the positions and movements of stars, planets, and other celestial bodies in the sky.

2. How is spherical astronomy different from other branches of astronomy?

Spherical astronomy differs from other branches of astronomy in that it focuses on the apparent positions and movements of celestial objects as seen from a specific location on the Earth's surface. This is different from other branches, such as astrophysics, which study the physical properties and behavior of celestial objects.

3. What are some common tools used in spherical astronomy?

Some common tools used in spherical astronomy include celestial globes, astrolabes, and sextants. These instruments help to measure the positions and movements of celestial objects in the sky.

4. How is spherical astronomy used in navigation?

Spherical astronomy has been used for centuries in navigation. By understanding the positions of stars and planets in the sky, sailors were able to determine their location and navigate their ships. Today, modern navigation systems still use principles of spherical astronomy.

5. What are some applications of spherical astronomy in modern times?

Spherical astronomy continues to play a crucial role in modern times. It is used in fields such as satellite navigation, astronomy research, and space exploration. It also has practical applications in fields like surveying and cartography.

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