ASTR-1010ASTR-1010Planetary AstronomyPlanetary Astronomy

Day - 19

AnnouncementsAnnouncements

Smartworks Chapters 4: Due Monday, March 1.

Smartworks Chapter 5 is also posted

Exam 2 will cover chapters 3, 4, & 5

-Target Wednesday, March 3

***Bring your Lecture-Tutorial books to the exam.

They will be collected and graded.

- Make SURE your name is in it!

Once a site with good “seeing” is Once a site with good “seeing” is found everyone wants to use itfound everyone wants to use it

Kitt Peak, AZ

Mauna Kea HawaiiMauna Kea Hawaii

Today most observations are Today most observations are done with a CCD Cameradone with a CCD Camera

CCD’s are much more sensitive CCD’s are much more sensitive than photographic filmthan photographic film

ClassAction StuffClassAction Stuff

• CCD Simulator

• Splash page questions

If you pass white light through a prism, it separates into its

component colors.

ROY G B I V

spectrum

long wavelengths

short wavelengths

Another common measuring Another common measuring device is the spectrographdevice is the spectrograph

The best spectrographs use The best spectrographs use diffraction gratingsdiffraction gratings

The spectrograph/CCD produces a The spectrograph/CCD produces a black & white spectrumblack & white spectrum

Spectra can be displayed as a Spectra can be displayed as a graph or rainbow of colorgraph or rainbow of color

Multitasking Saves TimeMultitasking Saves Time

But visible light is But visible light is only one type of only one type of electromagnetic electromagnetic radiation (light) radiation (light) emitted by starsemitted by stars

Astronomers are truly interested in the entire spectrum of Light!

Consider This Class as Seen in Different Wavelengths of Light!

Consider Orion as Seen in Different Wavelengths of Light!

Observations at other wavelengths are Observations at other wavelengths are revealing previously invisible sightsrevealing previously invisible sights

UV

Ordinary visible

infrared

Map of Orion region

Radio wavelength observations Radio wavelength observations are possible from Earth’s surfaceare possible from Earth’s surface

Observing In RadiowavesObserving In Radiowaves

Long Wavelength…poor resolution

Under the dish at AreciboUnder the dish at Arecibo

The Very Large Array (VLA)The Very Large Array (VLA)

Saturn In Different WavelengthsSaturn In Different Wavelengths

Visible

Near IR

Radio

Astronomers use different instruments to look at light of different wavelengths - sometimes, we even

have to go above Earth’s atmosphere.

Not all EM radiation can penetrate Earth’s atmosphere.

Atmospheric WindowsAtmospheric Windows

Telescopes and Earth’s AtmosphereTelescopes and Earth’s Atmosphere Lecture Tutorial Lecture Tutorial pg. 49pg. 49

• Work with a partner!

• Read the instructions and questions carefully.

• Discuss the concepts and your answers with one another. Take time to understand it now!!!!

• Come to a consensus answer you both agree on and write complete thoughts into your LT.

• If you get stuck or are not sure of your answer, ask another group.

Which is the correct reasoning for why a Which is the correct reasoning for why a gamma ray telescope located in Antarctica that gamma ray telescope located in Antarctica that is to be used to look for evidence of black holes is to be used to look for evidence of black holes in the centers of galaxies would not get funded?in the centers of galaxies would not get funded?

A. There is no way to detect the presence of a black hole.

B. Gamma rays are too energetic to detect with a telescope.

C. You can’t build a functioning telescope in Antarctica.

D. Gamma rays don’t penetrate Earth’s atmosphere.

Imagine you’re the head of a funding Imagine you’re the head of a funding agency that can afford to build only one agency that can afford to build only one telescope. Which of the four proposed telescope. Which of the four proposed

telescopes below would be best to support?telescopes below would be best to support?

A. A gamma ray telescope in AntarcticaB. A radio telescope in orbit above the EarthC. A visible telescope located high on a

mountain in PeruD. An ultraviolet telescope located in the Mojave

desert