Call
In astronomy, a guide star is a reference star used to accurately maintain the tracking by a telescope of a celestial body, whose apparent motion through the sky is primarily due to Earth's rotation.
Accurate telescope pointing and tracking is critical for obtaining good astronomical images and astrophotographs. However, because Earth rotates, the sky appears to be in a constant state of motion relative to Earth. Although this movement appears to be relatively slow when viewed with the naked eye, with the high magnification and consequently smaller field of view provided by even a small telescope, this motion becomes apparent on timescales of the order of seconds.
Though space telescopes are not mounted on a spinning planet, they still use guide stars including those listed in the HST Guide Star Catalog.
Computer-controlled electric motors are commonly employed to allow the telescope to move in sync with the apparent motion of the sky, according to a pre-computed pointing model. However, there is usually a significant non-zero error associated with the model, which is an approximation to the true motion of the sky.
Talk Doctor Online in Bissoy App