tip -- Declination: whether a star is visible from a location

VISIBLE WHEN: (90 - latitude + declination) > 0

1. Subtract your latitude from 90 degrees. This result is your co-latitude.
Example: 90 - 40 = 50
The co-latitude of 40 degrees north is 50 degrees.
2. To your co-latitude, add the declination of your star/constellation. South is negative.
Example: 50 - 53 = -3
3. If your co-latitude plus the declination of the star is greater than zero, then it will rise above your horizon at least sometime during the year.

Declination = degrees measured north or south of the celestial equator.