📍W2 L1 - Looking at the sky - Mapping the heavens Flashcards
Using coordinates in the sky
What is a sidereal day?
One full rotation of the Earth relative to background stars
How long is a sidereal day?
23 hours 56 minutes
What is a synodic day (also referred to as a solar day)?
One complete rotation of the Earth relative to the sun
How long is a synodic day?
24 hours
What is the celestial sphere?
The projection the universe makes onto the sky as viewed from Earth
What does the point of 0’ longitude cut through?
Royal Observatory in Greenwich UK
What is the equivalent of latitude projected onto the sky in astronomy?
Declination
What zone on Earth aligns with 0’ declination?
The equator
What is the name for the path the sun follows through Earth’s sky through the year?
The ecliptic
What angle is the sun’s path through the sky tilted relative to the celestial equator?
23.5’
What is the relationship between night and day length at the time of an equinox?
Night and day are the same duration at the equinox
What is the position of the sun’s path relative to the celestial equator at an equinox?
The ecliptic crosses the celestial equator at the equinox
What is the term used in astronomy for mapping longitude on the sky?
Right ascension
What time of year is used as 0’ for right ascension?
March - the time of the Northern Hemisphere’s vernal equinox.
When the Northern Hemisphere has its vernal equinox, what is the name for the equinox occurring in the Southern Hemisphere?
The autumnal equinox (sometimes called the fall equinox)
