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Astronomical Spectroscopy

Gerald Buxton, Zach Small, and Annika Gustafsson Professor Gregory Bothun

Dr. Scott Fisher

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Astronomical Spectroscopy Applications

Everything we know about the universe, in some way, relates to our observation of light from Earth.

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Some Applicable Examples:

  • Rotational Broadening
  • Temperature Broadening
  • Celestial Object Makeup

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Classical Spectrometers

  • Slit on which the light from source is focused
  • Collimator parallelizes the light
  • Diffraction Grating splits the light
  • Camera to Focus

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Useful Astronomical Terms

Absolute vs Apparent Magnitude

Apparent magnitude is a number that tells how bright that star appears at its great distance from Earth.

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m2-m1 = -2.50 log(B2/B1)

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Absolute Magnitude is the apparent magnitude the star would have if it were placed at a distance of 10 parsecs from the Earth.

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B10/Bd=(d/10)2

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Mv = m - 2.5 log[ (d/10)2 ]

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http://www.phys.ksu.edu/personal/wysin/astro/magnitudes.html

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Useful Astronomical Terms

Stellarium

Slew Speed

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Altitude/Azimuth

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1 = .5x*

6 = 64x*

1 = 1x*

7 = .5°

1 = 4x*

8 = 2°

1 = 8x*

9 = 3°

1 = 16x*

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* (sidereal)

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Progress for This Term

1. Align Telescope

    • Sky Align and Stellarium
    • Eyepiece to Fiber
    • Finderscope to Eyepiece

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2. Take data of well known object

    • Compare with known spectra

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1. Align Telescope

Sky Align and Stellarium

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1. Align Telescope

Align Eyepiece to Fiber

Lab Bench

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Purpose:

To align fiber in a controlled setting

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(Image of lab bench setup goes here)

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1. Align Telescope

Align Eyepiece to Fiber

Hall Test

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Purpose:

Align telescope and fiber with distance 105 ft, which is larger than focal distance of the telescope at 60 feet

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1. Align Telescope

Align Eyepiece to Fiber

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Hall Test

Hydrogen Lamp

4040 steps (red)

22 steps (green)

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1. Align Telescope

Align Eyepiece to Fiber

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Observing May 8: Streetlamp

Max in X (green), Max in Y (black)

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1. Align Telescope

Align Eyepiece to Fiber

Photon Emitter

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1. Align Telescope

Align Finderscope to Eyepiece

Red Point Source in Will 100

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2. Take Data of Well Known Object

Compare with known spectra

Saturn

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2. Take Data of Well Known Object

Compare with known spectra

Arcturus

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2. Take Data of Well Known Object

Compare with known spectra

Vega

Perfectly Calibrated Star

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2. Take Data of Well Known Object

Compare with known spectra

Vega

Perfectly Calibrated Star

Raw Data. This has all the information the Telescope picked up

Vega Spectrum with the Spectrum of the Night Sky subtracted from it, scan to averaged

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2. Take Data of Well Known Object

Compare with known spectra

Vega

Perfectly Calibrated Star

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Vega without Night Sky again

Vega from another group Vega Spectrum Atlas by the spectrometer MERIS

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2. Take Data of Well Known Object

Compare with known spectra

Vega

Perfectly Calibrated Star

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Vega without Night Sky again

Vega from another group Vega Spectrum Atlas by the spectrometer MERIS

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Going Forward...

Fiber Adapter

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Going Forward...

Optica

Optica Trouble:

Optica seems to be working fine and all of the components are drawn up, except for light rays are not being reflected, as you can see, so for now, we'll just leave the telescope specs.

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Top View

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Going Forward...

Telescope Specs

1) Primary Mirror

              • Spherical Mirror
              • Radius = 101.6mm
              • Hole Aperture = 38.1mm
              • Focal Ratio = F/2

2) Secondary Mirror

              • Schmidt Lense: Corrects for Spherical Mirror
              • Radius = 63.5mm
              • Magnifies the Primary Mirrors focal ratio by 5
              • Combination of Mirrors Creates a Focal Length of 2032 mm

3) Optical Tube Length

This is about 431.8mm (17 in). It changes as the telescope is focused.