However, I do know the angular size of the Sun (as seen from Earth) is about 0.53° -- yes, the distance from the Earth to the Sun does change, but I don't mind.

angular distance — the distance between two celestial bodies expressed in degrees, minutes, and/or seconds of arc. aphelion — the position of an object in solar orbit when it lies farthest ...

In 260 days, Mars will travel an angular distance of 136 degrees. That means the optimal time to launch the spacecraft is when Mars is 44 degrees (180-136) ahead of Earth in its orbit, as shown below.

Longitude, the vertical lines on a map, indicates the angular distance of points east and west of the prime meridian located in Greenwich, England. Got it?

While in two-dimensional space it may appear that Neptune and Pluto’s orbits intersect, the planets are, in fact, never in the same place at the same time. This is a result of their 3:2 orbital ...