To observe stars, they must be above the horizon, with their declination determining visibility based on the observer's latitude. At the equator, all stars with declinations from +90º to -90º are visible at some point in the year. Moving 20º northward limits visibility to stars with declinations no lower than -70º, as the South celestial pole dips below the horizon. Continuing north to the North Pole results in all stars with negative declination being permanently obscured. The declination and right ascension of a star remain constant over short periods, though they can change over long timescales due to proper motion and precession.
