I'm having trouble understanding how to solve a certain problem.
The problem is from the book Astronomy: Principles and Practice by Roy and Clarke. It is actually a solved example, but I am unable to understand parts of the solution.
Draw the celestial sphere for latitude 30° N, showing the star Sirius (right ascension 6h 40m, declination 17° S) at rising and draw the ecliptic. Estimate from your diagram the approximate date when Sirius rises with the Sun.
This is the image from the solution. I'll copy the entire solution.
Now, here's what I don't understand. If Sirius is at X, and if X is on a parallel of declination, why isn't this parallel parallel to the equatorial plane? Does the same go for the Sun? And how do we get the RA of the Sun?