Distance of the Stars

In all the optical instruments have focus and distance, so you apply distance and the instrument get out of focus and you make get focus again, with a accurate instrument connect in a computer that can calculate distance and focus you can make a calculation of centuries of distance of Earth, is right in the moment and others parameters of make the focus after the distance (the objective lens, that could be more than one) that the computer had calculate, so is relative relation distance and focus that gives the distance of the planet. Also in other point the calculation is relative and is very important the light, help in the calculation know what Star illuminate the planet and you discovery distance of the System that the planet is on, no problem the planet receive light of more one body, you can ignore all the others Stars and use only one, or use all the Stars to help the calculation, so is relative because you use others planets (they could mirror a light) and Stars to calculate the distance of the planets, and discover Solar Systems. Rute Bezerra de Menezes Gondim