1. Betelgeuse in Orion has to be aligned with the North Celestial Pole.

2. We said that the celestial pole is the pole of the Equatorial coordinate system. What do you think is the pole of the horizontal (Altitude/Azimuth) coordinate system? (The Zenith

3. Astronomical triangle Astronomical triangle A spherical triangle on the celestial sphere formed by the intersection of the great circles joining a celestial body, S, the observer's zenith, Z, and the north (or south) celestial pole, P (see illustration)

4. Coelostat, device consisting of a flat mirror that is turned slowly by a motor to reflect a portion of the sky continuously into a fixed telescope. The mirror is mounted to rotate about an axis through its front surface that points to a celestial pole and is …