Astronomy 109 Lab 1-5 Midterm Fall 2022 Flashcards
Scientific Notation: when the decimal is moved to the left the exponent is?
positive or +
Scientific Notation: when the decimal is moved to the right the exponent is?
negative or -
Scientific Notation: what is a million and prefix?
10^6, mega
Scientific Notation: what is a billion and prefix?
10^9, giga
Scientific Notation: what is a trillion and prefix?
10^12, tetra
Scientific Notation: what is a millionth and prefix?
10^-6, micro
Scientific Notation: what is a billionth and prefix?
10^-9, nano
Scientific Notation: what is a trillionth and prefix?
10^-12, pico
What is one degree equal in arcminutes?
60’ arcminutes
What is 1’ or 1 arcminute?
60” arcseconds
Astronomical Unit ( AU):
-used to express the average distance between earth and sun
- distance between earth and sun= 1 AU
What is 1 AU in miles and kilometers?
- kilometers:1.49x10^8
-miles: 9.29x10^7
Light year (ly):
the distance that light travels in a year, used to expressed distances of nearby stars
Celestial Sphere:
dome in which we see the sky
Declination ( DEC):
the angular distance of how high or low something is to the equator, analogous to latitude
Right ascension ( RA):
measured along the eastward equator, measured in time, ranges from zero point to vernal equinox
What is the equatorial co-coordinate system?
right ascension and declination
Parts of the celestial sphere
- Horizon:
the apparent line that separates earth from the sky
Parts of the celestial sphere
-Zenith:
the point directly overhead on the celestial sphere
Parts of the celestial sphere
-Meridian:
is the great circle passing through the zenith, due north and south points on the observers horizon, a star reaches its maximum height above the horizon when its on the median
Parts of the celestial sphere
- celestial poles:
the projection of the earths poles onto the celestial sphere
Parts of the celestial sphere
- celestial equator:
an extension of the earths equator onto the celestial sphere
Azimuth:
the angle measured eastward from the true north to the point of the horizon below the star and ranges from 0 degrees to 300 degrees
Altitude:
- how far above the horizon an object is seen in the sky
- altitude of Polaris = observers latitude ( in northern hemisphere )
What is Horizon Co-ordinate System?
Altitude and Azimuth
Constellation:
-pattern/groupings of stars named after
mythological animals, “characters” or objects
-examples: Andromeda, Perseus, Crux, Orion
Asterisms:
-Asterisms are the shapes within the
constellations, sometimes patterns are also formed by stars
in different constellations.
-example: The Big Dipper in the constellation Ursa Major,
Summer Triangle, Winter Triangle
Never-Set Stars:
DEC > 90 – LAT
Never-Rise Stars:
DEC < -90 + LAT
Rising/Setting Stars:
DEC < 90 – LAT and DEC > -90+ LAT
What is the importance of Polaris: the pole star?
- Polaris indicates the direction of true north as it sits on the NCP
- Altitude of Polaris = Observer’s Latitude (In Northern Hemisphere)
Parallax:
is the apparent shift in position of an object when the observer
views it from two different lines of sight
distance:
r to a celestial object
Finding the distance: r to a celestial object using the small angle formula:
Small-Angle Formula: r=(206265”)(d) divided by (a)
what does d represent in the small angle formula for finding distance?
where d is the separation between two perspectives
what does a represent in the small angle formula for finding distance?
𝛼 is the parallax angle in arcseconds
true or false: do you have to convert a into arcseconds in small angle formula for finding distance?
true
Finding the diameter: formula for celestial objects using the small angle formula
𝒅= (r)(a) divided by (206265”)
what does r represent in the small angle formula for finding diameter?
where r is the distance to the celestial object
what does a represent in the small angle formula for finding diameter?
𝛼 is the angular diameter of the object in arcseconds.
true or false: do you have to convert a into arcseconds in the small angle formula for finding diameter?
true
what is the formula for finding the mass of Jupiter?
Mjupiter=(4)(pi^2)(d)^3 divided by (G)(P)^2
what does P stand for in the formula for finding the mass of Jupiter?
-(seconds)^2
- is the orbital period of the moon in units of seconds
what does D stand for in the formula for finding the mass of Jupiter?
-(meters)^3
- orbital size/distance of the Jupiter’s moon in units of meters
what does G represent in the formula for finding the mass of Jupiter?
-G is the gravitational constant
- 6.673x10^-11 m^3/kg/s^2
what is the formula for finding the volume of celestial objects?
V=(4/3)(pi)(R)^3
what does r represent in the formula for finding volume of celestial objects?
where R is the radius of the object in meters
what star is in the summer triangle?
vega
what star is in the winter triangle?
Sirius
