Observational Astronomy

Astronomy

• Primary Goal: Understanding the nature of the universe and its constituents

• Means: Equipment building, research, teaching

General Areas of Study• Solar – the study of the sun• Planetary – the study of planets,

comets, asteroids, debris around other stars

• Stellar – the study of stars• Galactic – the study of our

Galaxy• Extragalactic – the study of

other galaxies• Cosmology – the study of the

origin & evolution of the universe

Research – Scientific Detective Work

• Hypothesis

• Tools/Sample to Test Hypothesis

• Propose for Observations

• Obtain Observations

• Reduce & Analyze data

• Modify Hypothesis

• Etc.

The “Laboratory” for Observational Astronomy

• Ground-based and Space-based Telescopes

• Computers - for processing data

• The internet - for transferring and sharing data, access to journals, etc.

• The classroom - where ideas are shared and developed with the next generation of astronomers

Good Observing Site

• Minimal number of cloudy nights• Minimal atmospheric turbulence

• Away from bright lights / cities• Low water vapor

Telescopes are thus located on Mountaintops

• Mauna Kea Observatories, located on Mauna Kea on the Big Island of Hawaii

• Elevation above sea level = 13,800 ft

… In Desert Valleys…

Owens Valley, California

… and in Space

• The “Seeing” at various sites: Long Island, NY: > 5”Kitt Peak, AZ: ~ 1.5”Mauna Kea, HI: ~ 0.5-0.8”HST: 0.05”Note: 60” = 1’

60’ = 1o

Not all wavelengths of light hit the ground

• This is one reason why some air/space-borne missions are necessary

Observing on Mauna Kea

• Observers sleep at a dormitory located at 10,000 ft• Then drive to summit with the telescope operator• 2 persion rule - due to dangers of working at altitude

Mauna Kea with Maui in the distance

Clouds typically are below 10,000 ft

The United Kingdom Infrared Telescope

Gemini Telescope on Mauna Kea

Secondary Mirror

Primary Mirror (8m Aperture)

Sunset on Mauna Kea – Gemini Telescope

• Open air design of the dome helps to reduce air turbulence in the dome

Secondary Mirror

PrimaryMirror

UKIRTDetectors are mountedbehind the primary

Observing• Most ground-based observational astronomy is

done at night• Observers are assisted by telescope operators

and support scientist

Observing

Some observations are done quasi-remotely (e.g., Keck) … Or very remotely (I.e., space based telescopes)

Observing

Some observations are done during the day Sometimes the observers is the telescope operator

Potential Problems

Clouds Ice

Software/Hardware Malfunctions

Support for Observational Astronomy

• National Aeronautics & Space Administration (NASA)

• National Science Foundation (NSF)

• Private Donors

Exciting Discoveries over the Last ~ 10 Years -

• The Kuiper Belt & its Bearing on the Nature of Pluto

• Extrasolar Planets

• Supermassive Black Holes in Nearby Normal Galaxies

• Galaxies at High Redshift

Goals for the Next 10 Years• Survey the universe & its constituents

• Use the universe as a unique lab for probing the laws of physics not accessible on Earth

• Search for life beyond Earth, & if it is found, determine its nature & its distribution

• Develop a conceptual framework that account for all that astronomers have observed