ASP Observational Techniques and Telescopes 2

Question 1

What is the magnitude scale in astronomy?

Accepted Answer

A logarithmic scale of stellar brightness where lower numbers indicate brighter objects

Answer

The magnitude scale is a logarithmic measure of brightness where each step of 1 magnitude corresponds to a brightness ratio of ~2.512, with lower (and negative) numbers indicating brighter objects.

Question 2

What is the difference between apparent and absolute magnitude?

Accepted Answer

Apparent is how bright a star looks from Earth; absolute is its intrinsic brightness at 10 parsecs

Answer

Apparent magnitude is how bright an object appears from Earth, while absolute magnitude is its intrinsic brightness defined as the apparent magnitude it would have at a standard distance of 10 parsecs.

Question 3

What is a charge-coupled device (CCD) in astronomy?

Accepted Answer

A highly sensitive electronic light detector that converts photons to electrical signals

Answer

A CCD (charge-coupled device) is a silicon-based electronic detector that converts incident photons into electrical charges with high quantum efficiency (~90%), revolutionizing astronomical imaging and replacing photographic plates.

Question 4

What is photometric redshift?

Accepted Answer

Estimating galaxy redshift from broadband photometry using color information across multiple filters

Answer

Photometric redshift estimates a galaxy's distance by fitting its observed colors across multiple broadband filters to spectral energy distribution templates, yielding an approximate redshift without time-consuming spectroscopy.

Question 5

What is the purpose of a coronagraph?

Accepted Answer

To block out the central bright source so faint nearby objects like exoplanets or the solar corona can be observed

Answer

A coronagraph is an optical device that blocks the direct light from a bright source (like a star) to allow observation of much fainter nearby objects such as the solar corona, circumstellar disks, or exoplanets.

ASP - Astronomical Society of the Pacific Exam Practice Test

ASP - Astronomical Society of the Pacific Exam Practice Test

ASP Observational Techniques and Telescopes 2