The celestial equator is the extension of Earth's equatorial plane onto the celestial sphere, so the two are coplanar; the approximately 23.44° angle is between the celestial equator and the ecliptic, not between the two equators. Stellar right ascension and declination depend on reference frame, epoch (such as J2000.0), precession, and proper motion; they are not perfectly constant. A figure-eight analemma is plotted from the Sun's position at the same clock time or mean solar time on successive days of a year. Using the same apparent solar time does not produce the same east–west equation-of-time offset. The international name Betelgeuse is preferable for a concise star label.