🔍 Key Concepts

• First point of Aries as the zero reference for right ascension in celestial navigation and astronomy • Relationship between declination and the Sun’s apparent motion along the celestial equator and ecliptic • What happens at the vernal equinox in terms of declination and seasonal change

💭 Think About

• Think about what the Sun’s declination is doing on the day of the vernal equinox: what is its value, and is it increasing northward or southward right after that? • The first point of Aries is used as a reference on the celestial equator. At that point, is the Sun at its maximum or minimum declination, or crossing through a particular value? • Which events (equinoxes vs solstices) are associated with maximum declination and which with zero declination?

✅ Before You Answer

• Verify which events give the Sun 0° declination (equinoxes) and which give maximum declination (solstices). • Confirm whether the first point of Aries is associated with the vernal equinox (northern spring) or the autumnal equinox. • Check in your notes whether, just after the first point of Aries, the Sun’s declination is moving toward northerly or toward southerly values.