Homework Flashcards
What is an alpha star?
The brightest star in the constellation
Are stars in constellations physically close to eachother ?
No remember the shadows on the projector screen
Sidereal day
Time between two transits of the first point of aries
Which is longer a sidereal day or a normal day?
Normal (solar) because of earths motion around the sun a sidereal day is roughly 4 minutes shorter
In the northern hemisphere it is colder in the winter than in the summer why?
Because in the winter the sun shines down at an angle
Sidereal day broad internet definition
The sidereal day is the time it takes for the earth to complete one rotation about its axis with respect to the “fixed” stars
Zenith?
Point in the sky or celestial sphere directly above the observer
How long does it take for the celestial sphere to make one full rotation?
24 hours (of right ascension)
One hour of right ascension is how many degrees ?
15 degrees because 24 hr x 15 degrees = 360 degrees
How many hours of right ascension are around the celestial equator?
24
Longitude?
How far something is east or west along the earths equator
Latitude ?
How far something is north or south of the equator (the distance north or south from the equator)
Right ascension
- like longitude
- locates where a star is along the celestial equator
- zero point is the vernal equinox
- the stars right ascension is from the zero point eastward to its spot on the hour circle
Zero point for right ascension ?
Vernal equinox
Ecliptic ?
The imaginary line in the sky that traces the suns path through the stars during a year
