I am working on an online application to visualize the positions of the planets and to calculate their ephemerides (you find it here, but it is not complete yet). I do not have much knowledge in astronomy and I am learning new stuff every day while developing the code. A few questions came to my mind that I hope to get answers for here.
The first thing I do not quite understand is the effect of the earth's axial precession. I understand the way it causes the vernal point to move along the ecliptic within the period of the precession of about 25770 years. But since the longitude of the ascending nodes of each planet's orbit depend on the vernal point and remain almost constant over time it seems like all the orbits change their position relative to the stars at the same rate as the vernal point does. But I cannot believe that the orientation of the orbits is related to the precession of the earth's axis.
You can see the effect in the application: When you move the topmost time slider for years you can see the zodiac rotate and the orbits staying in place because the vernal point is fixed with the scale. Shouldn't the orbits move together with the stars? But then the longitude of the ascending nodes wouldn't be constant anymore... I am confused. Thank you.