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Modern Observational/Instrumentation Techniques Astronomy 500. Andy Sheinis, Sterling 5520,2-0492 [email protected] MW 2:30, 6515 Sterling Office Hours: Tu 11-12. Class Website: Handouts, .ppt lectures and HW will be posted http://www.astro.wisc.edu/~sheinis/~500class. Homework: - PowerPoint PPT Presentation
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Modern Observational/Instrumentation
TechniquesAstronomy 500
Andy Sheinis, Sterling 5520,2-0492 [email protected]
MW 2:30, 6515 Sterling
Office Hours: Tu 11-12
Class Website:Handouts, .ppt lectures and HW will be postedhttp://www.astro.wisc.edu/~sheinis/~500class
Homework:There will be a 5-6 problem sets, one due approximately every other week. I will either post, or handout solutions. I encourage you to discuss the problems with your classmates, but you must each write up your own solution.
There will also be a Midterm and Final exam as well as an “Observational” project, which may or may not
include a laboratory exercise.Grading: Approximate grading distribution will be:
HW 40%Project 20%Midterm 20%Final 20%
Texts:
Required:Walker, "Astronomical Observations", Cambridge Univ. Press.Schroeder, "Astronomical Optics", Academic Press
Recommended:Kitchin, "Astrophysical Techiques", Adam Hilger, LtdBevington&Robinson, "Data Reduction and Error Analysis for the Physical Sciences", McGraw-HillGray, “The Observation and Analysis of Stellar Photospheres”, Cambridge U. Press
Other Useful References:McLean, “Electronic Imaging in Astronomy”, WileyRybicki and Lightman, “Radiative Processes in Astrophysics”, WileyCox, “Allen’s Astrophysical Quantities”, Athlone Press
chaptersDate title W K S G R & L
1/22/06 Introduction to the course. Basic Observables 1 61/23/06 Photon Fluctuations, Fundamental noise sources, S/N 2 41/29/06 S/N in aperture photometry 2 41/30/06 Detection Limits/ Signal-to-noise/ time estimation 2 1.1 16
2/5/06 Planning an Observing run2/6/06 Basic Processing
2/12/06 Basic Processing2/13/06 Intro to Optics: Fundamentals/ radiometry 2 5 12/19/06 Intro to Optics: Paraxial Optics, Wave Optics 102/20/06 Detectors revisited 8 162/26/06 Telescopes 3 4, 7 ,8, 102/27/06 Telescopes 3 4, 7 ,8, 10
3/5/06 seeing, speckles and scintillation 4 53/6/06 seeing, speckles and scintillation 4 2
3/12/06 Direct imaging resolved and unresolved source photometry 2.1, 2.3, 33/13/06 Direct imaging resolved and unresolved source photometry 2.1, 2.3, 33/19/06 Spectrographs: Basics 7 4 13, 15 33/20/06 Spectrographs: Basics 7 4 13,15 33/26/06 Spectrographs: Specialized, MOS, IFU 43/27/06 Midterm
4/2/06 spring break4/3/06 spring break4/9/06 Spectoscopy: Processing techniques 7 4
4/10/06 Measureing spectral Continuum 7 104/16/06 Measureing spectral Lines 7 124/17/06 Student Presentations4/23/06 Student Presentations4/24/06 Polarimetry: Nordsieck 5.24/30/06 Fabry-Perot: Reynolds
5/1/06 Radio: Eric Wilcots 1.25/7/06 Radio: Eric Wilcots5/8/06 Review.
* W=WalkerK=KitchinS=SchroederG=GrayR&L=Rybicki and Lightman
Astronomy is Different
• Universe is the laboratory• We can only observe, no interaction• Limited to phenomena, occuring in the past• Must take interpret a “snapshot”• Have only the properties of light• Cannot measure directly, must infer from the
measurement of light.
Properties of light
• Intensity, flux, irradiance, amplitude
• Angle of arrival, position, image
• Wavelength, frequency, color
• Angular momentum, spin, polarization
• time variation (in some cases)
• Phase (interferometry, radio, AO)
LargeTelescopes
• Only two (Keck I and II) available in the 90’s• Several available at the turn of the century (the 4
VLT units, Gemini North and South, Subaru, HET)• One more in 2005, SALT!• others under construction (LBT, GTC)• and plans already for 30-100m telescopes...
Telescopes• Name Diameter Nationality of Sponsors Site Built• (SALT) 11.0 m South Africa, USA, UK, Germany, Poland, New Zealand South African 2005• (GTC) 10.4 m Spain Roque de los Muchachos Observatory, Canary Islands 2005• Keck 1 9.8 m USA Mauna Kea Observatory, Hawaii 1993• Keck 2 9.8 m USA Mauna Kea Observatory, Hawaii 1996• (HET) 9.2 m USA, Germany McDonald Observatory, Texas 1997• (LBT) 2x8.4 m USA, Italy, Germany Mount Graham Arizona 2004• Subaru (NLT) 8.3 m Japan Mauna Kea Observatory, Hawaii 1999• VLT 1 (Antu) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 1998• VLT 2 (Kueyen) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 1999• VLT 3 (Melipal) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 2000• VLT 4 (Yepun) 8.2 m ESO Countries (European + Chile) Paranal Observatory, Chile 2001• Gemini North 8.1 m USA, UK, Canada, Chile, Australia, Mauna Kea Observatory, Hawaii 1999• Gemini South 8.1 m USA, UK, Canada, Chile, Australia, Cerro Tololo Observatory, Chile 2001• (MMT) 6.5 m USA Fred Lawrence Whipple Observatory, Arizona 1999• Magellan 1 6.5 m USA Las Campanas Observatory, Chile 2000• Magellan 2 6.5 m USA Las Campanas Observatory, Chile 2002• BTA-6 6 m Russia Zelenchukskaya, Caucasus 1976• Large Zenith Telescope (LZT) 6 m Canada, France Maple Ridge, British Columbia 2003• Hale Telescope 5 m USA Palomar Observatory, California 1948
Flux
Flux is energy incident on some area dA of the Earths surface. Flux is not conserved and falls of as R-2.
€
dE = fυ dAdυ dt
dE = fυ (4πR2)dυ dt = Lυ dυ dt
∴ fυ =Lυ
(4πR2)
Flux
• Flux is measured in Janskys in the radio• 1Jy=10-26 W m-2 Hz-1
• In the visible flux is measured in apparent magnitudes
€
m1 −m2 = −2.5log10
f1f2
⎛
⎝ ⎜
⎞
⎠ ⎟
m = −2.5log10
f1f0
⎛
⎝ ⎜
⎞
⎠ ⎟
Flux: absolute magnitude
• Absolute magnitude is the apparent magnitude that would be observed at 10 pc.
• A is the total extinction due to intersetllar dust in magnitudes
€
mλ −Mλ = 5log10 d − 5 + A(λ )
Qf1f2
=d2
d1
⎛
⎝ ⎜
⎞
⎠ ⎟
2
Standard choices for reference flux
• Vega system: apparent Magnitude of Vega = 0 in all bands.
• Convenient, but non-physical• A-B magnitude system:• F0=3.63e10-23 W m-2 Hz-1, flat spectrum• Agrees with Vega at 548nm (center of
V-band)
Interesting magnitudes (V-band)
• Sun: m=-26.7• Full moon: m=-12.6• Sirius: m=-1.5• Naked eye limit: m=6• Brightest stars in Andromeda: m=19• Present day limit: m~29• Night sky: m=21.5 (best sites, dark time)• Night sky: m=18 (bright time)
Intensity
• Finite size source (subtends a real angle)• Specific intensity• Brightness, surface brightness• Specific brightness• Units: (Jy sr-1) or (W m-2 Hz-1sr -1) or (erg cm-2
Hz -1) or (m arcsec-2)• What happens when the source is not
resolved?
Intensity
• Omega measured in RA and Dec• v= frequency• t= Integration time• P=polarization• Location where you are receiving the light.
€
dE = Iυ (Ω,υ , t, p)dΩdυ dt dA
Where I will depend on:
Observation
• E=energy received during measurement• R=energy from the sky• F= filter function€
E = ∫ Iυ (Ω,υ , t, p) r(Ω)F(υ )dΩdυ dt dA
E = AΛt ∫ Iυ (Ω,υ , t, p) r(Ω)F(υ )dΩdυ