Ch 2 The Night Sky Flashcards
Magnitude
what is the 0.0 point
what is the max magnitude of the sun?
Of neptune?
Measures brightness and works on a logarithmic scale.
- 0= Vega
- 26.7 - 6
if something is 100x dimmer than vega, what is its magnitude?
approx 5
What magnitude can humans see with a naked eye?
With a telescope?
m= 6.5 ( so we can see approx <10k stars) m= 31
What planets are visible to the naked eye?
Mercury, venus, mars, jupiter, saturn.
(T/F) The scale of apparent visual magnitudes extends into negative numbers to represent the faintest objects in the sky.
False.
neg numbers = brighter objects
How many constellations are there?
88
Are stars too far away for depth perception
yes.
Hence why the ancient people called it the celestial sphere.
TRUE/FALSE FOR DA SPHERE OF CELESTIAL
Does earth’s northpole point towards the celestial north pole?
The earth’s equator expands out to the celestial equator
The sun follows a uniform pattern on the celestial sphere.
Dumb happenstance, but yes.
true af
FALSE. It does not
What are the tropics?
The tropics are the point at which the sun’s path is the most north and most south. ( cancer and Capricorn)
The stars in a constellation are named based on their apparent magnitudes. list top three brightest
alpha
beta
gamma
What is the alpha in orion? The beta?
A= betelgeuse
B=Rigel
What is an asterism?
Well known shapes that are not actually constellations (ex big dipper)
How many zodiac constellations are there?
13.
Ophiuchus
What determines what month a zodiac constellation is associated with?
The time the constellation is behind the sun.
Why is winter colder in the northern hemisphere?
Because of earth’s tilted axis.
Define solar day
note, earth moves 1 degree a day.
The time it takes forthe sun to retur to the same position overhead
24h=361 degrees
Define Sidereal Day
The time it takes for the stars to return to the same position in the sky;
23hr 56 min = 360 degrees.
T/F the sun follows a uniform path
T——-FALSE!!!!
Changes over the seasons due to the tilt of the earth’s axis.
How much is earth’s axis tilted?
23.5 degrees
Draw axial tilt diagram. include: ecliptic, celestial equator celestial north and south pole ecliptic axis
see diagram
see desktop
When do equinoxes occur?
When the axial tilt is perpendicular to the line connecting earth to the sun
If earth rotated about an axis perpendicular to its orbit, what would we fail to experience?
365 days a year
Which axes points towards the celestial poles?
earth’s rotational axis