Observing the Night Sky Flashcards
What is right ascension?
Right ascension is the angular distance measured eastward along the celestial equator from the vernal equinox to the hour circle of the point in question.
What is declination?
The angular distance of a point north or south of the celestial equator.
What is the declination of Polaris?
+90 degrees
Why does Polaris seem fixed in the night sky?
As the star is at +90 degrees this means that it is directly above the note celestial equator, this means that it is directly above the Earths rotation point therefore it doesn’t seem to move.
Why is the elevation of Polaris the same as the observer’s latitude?
Because Polaris is directly 90 degrees above the equator meaning that its elevation would be +90 degrees if the observer had a latitude of +90 degrees.
What is the equation for a star to be circumpolar.
Declination > 90 – latitude
What is the ecliptic?
The ecliptic is the apparent path of the Sun on the celestial sphere.
What is the zodiacal band?
The narrow region of sky through which the planets appear to move.
Plan the equipment needed for a naked-eye observation session.
Red torch, clipboard, pencil/rubber, warm clothes.
What are some naked-eye observing techniques.
Dark-adapted eye, relaxed eye and averted vision.
Explain the apparent east-west motion of the night sky.
Stars appear to move across the night sky. As the Earth rotates in an anticlockwise direction, the east-west motion of the night sky becomes apparent. The position of the distant stars is fixed, we are the ones moving.
