If a star passes through your zenith and your latitude is 35°, what is the star's declination?

If a star passes through your zenith and your latitude is 35°, what is the star's declination?

• A. 0°
• B. −35°
• C. 35°
• D. 90°

Answer: (C)

Declination is like celestial latitude, measuring how far north or south an object is from the celestial equator. The zenith—the point directly overhead for you—lies on the local meridian at a declination equal to your latitude. So if you’re at 35° latitude, the zenith sits at declination +35°. A star that passes through your zenith must have that same declination. Therefore, the star’s declination is +35°. (If you were in the southern sky, it would be negative, but here it’s north.)

Declination is like celestial latitude, measuring how far north or south an object is from the celestial equator. The zenith—the point directly overhead for you—lies on the local meridian at a declination equal to your latitude. So if you’re at 35° latitude, the zenith sits at declination +35°. A star that passes through your zenith must have that same declination. Therefore, the star’s declination is +35°. (If you were in the southern sky, it would be negative, but here it’s north.)