Unit 6- Celestial Observations Flashcards
How many constellations are there in the sky?
88
What is an asterism?
A well recognised pattern that’s either in a constellation or made up of brighter stars from more than one constellation
What does the latitude of Polaris tell you about the observer?
The latitude of Polaris = the latitude of the observer
What is the azimuth?
The bearing from North (clockwise)
What is the altitude and what does it tell you if the altitude is: 1.) 0 degrees 2.) 90 degrees 3.) No azimuth
The altitude is the angle above the horizontal outwards
1.) Then it’s at the horizon
2.) Then it’s at its zenith (the highest point)
3.) No azimuth= altitude of 90 degrees
What is the celestial sphere?
An imaginary sphere centred around the Earth, which we image all the objects in the sky and can plot it on so we can measure and understand their apparent positions. Most stars DO NOT FALL INTO THE EARTH’S SPHERE BECAUSE THE EARTH’S NOT IN THE CENTRE OF THE SOLAR SYSTEM
What is declination?
The latitude of a star from the celestial sphere
How far or below a position is from the celestial equator
Measured in degrees, arc minutes and arc seconds
What is the Sun’s Right Ascension and Declination at midday on March 21st?
RA of 0 hours
Declination of 0 degrees
Which way do stars move around Polaris at night?
They move ANTICLOCKWISE
What is the relationship between your latitude and the North Celestial Pole?
Your latitude = altitude of NCP
How to find the polar distance of a star?
90 degrees - declination of the star (no. of degrees from the NCP)
How to find the altitude of the Upper and Lower Transit?
Altitude of Upper Transit = Latitude of observer + Polar distance
Altitude of Lower Transit = Latitude of observer - Polar distance
What are meteors and how are they formed?
Meteors are dust, grit sized chunks of rock that are made out of stone, ice and metal and orbit the Sun
They are formed from debris left from a path of disintegrating comets that produced a meteor stream
They can also be formed from collisions of asteroids with objects (e.g Mars or the Moon)
