Astronomy assesment flashcards!

For the BMG! year 9 assessment

Galaxy clusters meaning?

A galaxy cluster is a group of galaxies that are gravitationally bound to eachother

What is the Local galaxy?

A group of about 50-80 galaxies gravitationally bound together that WE are in currently

All galaxy shapes?

Galaxy shapes:
- Elliptical galaxy
- spiral galaxy
- irregular galaxy
- Barred spiral galaxy

What is the cosmic web?

• The cosmic web is the backbone of the universe and the formation began after the big bang with tiny density fluctuations.

• it supplies all galaxies with dark matter and gas to form galaxies and fuels their growth/evolution

What is the Virgo supercluster?

• Also known as the Local supercluster due to us being in this supercluster, the Virgo supercluster is a massive structure that spans approximately 110 million light years

• The Virgo supercluster contains thousands of galaxies with one of them being the milkyway

What is the Lanikea megacluster?

• the Lanikea megacluster contains approximately 100,000 galaxies and it spans 500 million light years
  

• Lanikea is defined by the gravitational pull of the great attractor which is a massive unseen mass that pulls galaxies towards it

Label A-H on this telescope

A = Guide scope

B = Guide scope camera

C = Tracking computer

D = Telescope

E = Imaging camera

F = Mount

G = Counterweight

H = Stand

What is a celestial pole?

A celestial pole is the point that stars appear to rotate around

What is the Stand used for?

The stand is used to hold the Telescope and all its weight up and too make sure tiny vibrations don’t interrupt the imaging process

What is the Telescope mount used for?

Consists of two motors that can accurately and precisely move the Telescope for imaging

What is the Imaging camera used for?

Used to collect the image from the camera from the main telescope

What is the Telescope used for?

Used to change the FOV and increase light collection capability of the camera

What is the Guide scope used for?

Used to guide the telescopes motion by tracking stars in par with the guide scope camera and tracking computer

What is the Guide scope camera used for?

Used as the eyes for guide scope so it can properly track moving celestial objects without needing that much human input

What is the Tracking computer used for?

Used to target and not lose track of whatever you are trying to process into becoming an image in par with the guide scope camera and guide scope with the guide scope camera and the guide scope being the eyes whilst the tracking computer is the brain

What is the Focal ratio and how is it expressed?

• The focal ratio is the objective focal length to the apeture

• It is expressed as f/No.

Is it better or worse to have a higher focal ratio explain?

• it actually depends on the situation
  - Higher focal ratios is good for planetary views
  - Lower focal ratios are good for deep-sky work

What is resolving power?

Resolving power is the ability to distinguish two nearby objects.
- It’s incredibly similar to resolution of a monitor and its pixel size
- larger apetures give better resolving power