Spherical Astronomy Problems And - Solutions [extra Quality]

Better to say: The star is above horizon when (|H| < H_0) with (H_0 = \arccos(-\tan\phi\tan\delta)). For this example, (H_0=115.7°), so visible for (2\times115.7/15 \approx 15.4) hours.

Rise, transit, and set times

Substitute: $$ \cos H = - (0.839 \times -0.176) $$ $$ \cos H = - (-0.147) $$ $$ \cos H = +0.147 $$ spherical astronomy problems and solutions

The parallax method is used to measure the distances to nearby stars. The parallax is the apparent shift of a star's position against the background stars when viewed from opposite sides of the Earth's orbit. Better to say: The star is above horizon