Astronomy Flashcards
Explain the pinhole method
When the sky is clear. Put a hole through a piece of paper. Position a second piece of paper behind and adjust the distance between them to bring the sun into focus.
Describe the appearance of the milky way with the naked eye.
A faint patch of light.
Why are time zones used on Earth?
Time zones are used to standardise sunrise and sunset hours for people living in locations which receive light from the sun at different times.
What are sundials used for?
Sundials are the earliest type of clock and use the Sun and its position to indicate the time of day, commonly known as solar time.
What is the equation for equation of time.
EOT = AST - MST
How will a meteor appear across the sky?
A split second as a bright streak of light probably from the tail of a comet burning in the atmosphere.
How many constellations are there in the sky?
88
What is a asterism?
Unofficial popular patters of bright stars in a constellation.
What coordinate system do we use to find constellations or stars.
Equatorial coordinate system in which equivalents of our latitude are declination and Right ascension.
Where is Right Ascension measured?
Eastwards from the first point in Aries.
What is a coordinate system that is more observer friendly than the equatorial system?
Horizontal system using azimuth and altitude.
How long is a sidereal day?
23 hours 56 minutes 4 seconds
What is the equation for hour angle?
Hour angle = local sidereal time - right ascension.
What does NCP stand for astronomy.
North celestial pole.
What is a circumpolar star?
A star that never sets below the horizon due to its proximity to the poles.
How are stars circumpolar?
The polar distance must be less than the altitude of the NCP.
What is the equation for a star to be circumpolar?
90 - declination < latitude of observer
How long does it usually takes the eyes to become dark adapted?
20 - 30 minutes.