Summary

• These four images were used to calibrate the spectrum measurements for August 6, 2010.
  • Image: vega08062010-01405s.fit
  • Image: vega08062010-01505s.fit
  • Image: vega08062010-01605s.fit
  • Image: vega08062010-01705s.fit

Spectroscopy Team

The spectrum image was taken by the below spectroscopy team.

• David Haworth, Amateur Astronomer
• Kevin Carr, Professor of Science Education, Pacific University College of Education
• Anders Benson, Pacific University
• Doug Neill, Pacific University
• Ryan Gasik, St. Mary's High School

Spectrum Calibration

• The star Vega H-alpha absorption line was used to calibrate the x axis in angstroms by measuring the distance of the grating to CCD.
  • Images of Vega spectrum were taken at the beginning of each evening imaging session.
  • Vega H-alpha absorption line distance was measured from the centroid of the spectral order zero.
  • The below table shows the four images used and the calculated grating distance between the grating and the CCD.
  • The grating distance mean is 18.3272 mm with a standard deviation of 0.01414 mm.
     
  
   
  SpectrumCalWithVega08062010.xlsx

• The first calibration equation is Å =SIN (ATAN (0.0000068* pixel distance /.01832719265135))*0.000005*10000000000
  • Å is light wavelength measured in angstroms.
  • 0.0000068 m is QSI532ws pixel size (6.8 microns).
  • Pixel distance is the horizontal pixel distance from the centroid of spectral order zero.
  • .01832719265135 is the distance of the grating to CCD (18.3272 mm).
  • 0.000005 m is the distance between the Rainbow Optics grating filter lines (200 lines/mm grating).
  • 10000000000 converts the wavelength from meters to angstroms.
• The second calibration equation is a linear x=Ay+B between absorption lines to align the H-alpha, H-beta, H-delta and H-gamma absorption lines of image vega08062010-01605s to the CCD pixel distance to the centroid of the zero mode image.

vega08062010-01405s.fit Spectrum Chart

vega08062010-01505s.fit Spectrum Chart

vega08062010-01605s.fit Spectrum Chart

vega08062010-01705s.fit Spectrum Chart