1
$\begingroup$

Well, I have this picture and a couple of tasks to it:

enter image description here

It is the Sun's path, a.k.a. ecliptic in autumn, 22-23 of September or on the day when autumnal equinox happens. I am to answer these questions:

  1. In the arc of what big circle does the Sun make its daily movement on this day?
  2. Which points of the celestial sphere are the poles of this circle?
  3. At what points on the horizon does the Sun cross it on this day?

My asnwer to the first question is ecliptic. I may misunderstood the second question but I think it is these points (taken from here):

  • North: right ascension 18h 0m 0.0s (exact), declination +66° 33′ 38.55″
  • South: right ascension 6h 0m 0.0s (exact), declination −66° 33′ 38.55″

But how do I answer the third question: does the Sun cross them over that day?

$\endgroup$
4
  • 1
    $\begingroup$ I don't think your answer to question 1 is right, and that follows through to the rest of the question. Try a stellarium simulation. Turn on the ecliptic and equatorial grids and zoom back a little to see the full path of the sun on the 22nd of sept. $\endgroup$
    – James K
    Commented Nov 14, 2021 at 8:55
  • 1
    $\begingroup$ Because the point of autumnal equinox is the point of crossing between ecliptic and celestial equator, we can say the Sun moves along the celestial equator. $\endgroup$
    – ALiCe P.
    Commented Nov 14, 2021 at 10:42
  • 1
    $\begingroup$ By "poles of this circle" they probably meant north and south celestial poles and the third question is just probably about the fact that in that day the Sun rises exactly in the east and sets exacly in the west. $\endgroup$
    – ALiCe P.
    Commented Nov 14, 2021 at 10:51
  • 3
    $\begingroup$ I think you could write your own answer now. $\endgroup$
    – James K
    Commented Nov 14, 2021 at 11:03

0

You must log in to answer this question.

Browse other questions tagged .