1. The problem statement, all variables and given/known data The moon Titan has an angular diameter of 4.4mrad as seen from the surface of Saturn. The sun has an angular diameter of 9.3mrad as seen from the surface of the earth. Which of the following eclipses cannot be seen from the surface of Saturn (a) A lunar eclipse of Titan by Saturn (b) A partial solar eclipse due to Titan (c) A total solar eclipse due to Titan (d) An annular sola eclipse due to Titan 2. Relevant equations I have no idea, I'm guessing perhaps equations involving angular speed/frequency/period? 3. The attempt at a solution So I have just completed my AS levels and have never encountered any prior work that is similar to this question, therefore I'm at a complete loss as to where to begin or how to answer the question. My guess would be that the total solar eclipse could not happen as Titan has a smaller angular diameter than the sun so would not totally block the light but I am not sure. If someone could explain the answer to me (as this is all completely new to me) then that would be much appreciated. I looked on wikipedia and it talked about angular diameter in terms of arcseconds so I'm not sure what that means. Thank you.