midterm 1 Flashcards
Polaris
star that never changes its position in the sky
Brightest objects in the sky?
- Moon
- Venus
- Jupiter
The early universe was what?
Opaque because it was the heat of the sun
3 components of the sun
hydrogen, helium, oxygen
Largest galaxy?
M31 or Andromeda galaxy
Asterism
unofficial name for a group of stars
Constellations
official name for star patterns
Are the Big Dipper and the Little Dipper the official names?
No they vary they are asterisms
How many known constellations are there?
88
How are the constellations defined?
By the IAU
How many zodiac constellations are there?
13
Who was the man who created the zodiac signs and how are they made?
Talloman was the man who tracked when the sun enters/exits the constellation
Declination
controls latitude
-90 – 90
Right Ascension
Longitude
divided by time (of the stars)
Hipparchus
created first star map first to predict an eclipse would occur
Magnitude
how the brightness of stars is measured
What is the most important factor in classifying stars?
temperature
How much magnitude can the human eye see?
6th magnitude
Where can you see the pole star?
Northern Hemisphere
Culmination
for stars to get to their highest point when they are due south and it is the best time to observe them
Zenith
highest point in the sky
Nadir
the lowest point in the sky
Meridian
line where objects get their highest, everything rotates around the meridian
Circumpole star
never sets because its too close to the pole star
North Pole facts
sun is up for 6 months and down for 6 months
half the sky can never be seen
stars just go around the horizon
Equator
stars come straight up in the sky
pole star is on horizon
only place on earth where the entire sky is visible (not at once)
Circumstar Sky
the sky you can always see
Main stars in Circumstar sky
Ursa Major
Draco
Cepheus
Cassiopeia
Camelopardalis
Seasonal Sky
changes with the seasons, don’t always see the same stars
First point of Aries
the point where the sun crosses the celestial equator
the zero point of right ascension
Vernal Equinox
when the sun crosses there point of time of the year (21 march)
In the North Pole do the stars rise and set?
No they go around the horizon
t/f half the sky can never been seen in the northern hemisphere
true
t/f the stars in the equator come straight up
true
3 stars closest to earth?
alpha centuri a
alpha centuri b
proxima
Where was the first transmission across land
ireland in 1894
Are star motions predictable?
Yes the same stars appear at the same time of the year
What is the 13th constellation?
ophiuchus
How were stars classified?
using greek letters
What do Am and PM mean?
after the meridian / before the meridian
