Is there a term for the vertical elongation of a planet?

[dotancohen]

Is there a term for the vertical elongation of a planet? This would be the angular distance above the horizon that a planet appears at the instant the sun sets, or in mathematical terms it would be:

x=elongation
theta=angle between the ecliptic and the horizon

"vertical elongation" = x * sin(theta)

 

[dotancohen]

Note that the formula assumes that the planet actually lies on the ecliptic, which of course is rarely the case. But I use the formula to illustrate.

 

[SpiffyKavu]

Yes indeed, such a word exists. If a sphere is elongated along its semi-minor axis (vertically, in this case), then it is known as a prolate spheroid. This is opposed to a oblate spheroid, in which the sphere is elongated at its equator.

So to answer your question: "prolateness", I suppose would work. And the dictionary confirms that it is a word.

 

[dotancohen]

Thanks, SpiffyKavu, but I think that we are using different definitions of "elongation". I am using "elongation" in the sense of angular distance from the sun:
http://en.wikipedia.org/wiki/Elongation_(astronomy)

I do not refer to a physical feature of the planet's material, but rather the planet's position in the sky relative to the sun. I apologize, I thought that the definition would be clear here from the context. In fact, I did not even think of the other definition.

 

[sardar]

I can confirm that there is indeed a term for the vertical elongation of a planet. It is known as the "vertical altitude" or "vertical distance" and is measured in degrees above the horizon. This term is commonly used in astronomy and is an important factor in determining the position and visibility of a planet in the sky. It is calculated using the formula mentioned above, where x represents the elongation and theta represents the angle between the ecliptic and the horizon. I hope this clarifies the concept of vertical elongation for you.