How to Calculate the Speed of Light

If speed of light was infinite, then io would always appear every forty two and a half hours. But because the distance between earth and io is growing or shrinking, then this period grows or shrinks. So that the time between io emerging from behind jupiter getso ger during one season and shorter during other seasons. Somehow that tells you the speed of light. Is that wo mea sometimes it moves a lot in that time? And so when we are moving further away from io, during that part of the year that we're like zooming away from it, then those times will get longer.