In Astronomia Nova (1609) Johannes Kepler used observations of Mars in order to refute circular orbits. Throughout Astronomia Nova he hardly even mentions other planets than Mars, Earth and the Sun ...
How does one compute the right ascension and declination of the Moon at a given time (or for that matter, the altitude and azimuth)?
I have a question for homework and don't get it at all: Consider two filters as shown in the figure below. Compute the colour S1 - S2 in the AB system for a star with flux: where is a constant ...