I am trying to figure out the eclipse periods of a satellite orbiting the Earth. The satellite is placed on a circular sun-synchronous orbit at 800 km height. The LTAN (local time of ascending node) is 11:00 am. First question, what exactly is LTAN? And how is it related to the other orbital parameters (like eccentricity, inclination etc.)? Second, how can I use it to compute the eclipse periods?