Two of the precautions observed in this and similar series of measures are the taking of all th6 plates at small hour-angles, so as to minimise the effect of unequal atmospheric dispersion in the ...

Parallax is the observed displacement of an object caused by the change of the observer's point of view. In astronomy, it is an irreplaceable tool for calculating distances of far away stars.

Hurtling through interstellar space 4.3 billion miles from home, NASA’s New Horizons spacecraft has traveled so far that it has a unique perspective of the stars.