Astronomy Cafe – May 17, 2021

Posted by as Astro Cafe

Video transcript of meeting

VIdeo frame of ISS taken through an 8" Dobsonian by Nathan
VIdeo frame of ISS taken through an 8″ Dobsonian by Nathan
  • ISS photo – Nathan Hellner-Mestelman
    • Used a iPhone mount using a 30-min video slow motion through a 5mm  eyepiece, 2.5x Barlow and 8″ Dob (1,200mm f/l), so about 600x magnification, 2-3 arc secs 
  • Astronomy Day on May 15th – Randy Enkin & Lauri Roche
    • We were so fortunate to have a clear sky for this online event
    • Reviewed all the presenters and thanked everyone
  • Spectroscopy – Tom Field
    • Intro by David Lee
    • 70-80% of astronomical research is done with spectroscopy
    • Rspec-Astro.com – spectroscopy software for amateur astronomers
    • Bunsen invented his burner to burn elements to see their component spectra
    • Emission and absorption lines in spectrum
    • “The Computers” Annie Jump Cannon – they created categories for spectral plate analysis
    • Equipment to use for capturing spectrum
      • Star Analyser Grating – US$195
      • Other adapters and gear available
      • A slit instead of a grating, which yields more resolution, but costs more and requires better technique
    • Compared spectra of 8 different stars – Torsten Hansen
    • Doing science
      • Graph the results
      • Spectroscopy is more immune to light pollution than traditional astrophotography, so urban observing works
      • Wolf-Rayet stars (WR140) – shows this late-stage star with carbon-rich spectra
      • Spectra can be measured of: planets, comets, meteors, the Sun, Supernova, stars
      • Measuring Doppler Shift, or is it red/blue shift?
      • Extended objects like nebulae need a slit instead of a grating
      • Black Hole? no, but the accretion disk emits light
      • Calculating red shift
    • Spectroscopy can reinforce other observational skills
    • Distance between sensor and grating needs to be precisely setup
    • Emission versus absorption lines
    • Can use other grating, since RSpec can calibrate to other grating resolutions. RSpec grating uses 100 lines/mm which is easy to use, and yields brighter spectra.
    • Calibrate on a known star, then study other objects

Notices

  • There is no Astro Cafe next Monday due to the Victoria Day holiday. The next Astro Cafe is scheduled for May 31st.
  • If anyone would like to lead a citizen science group, please contact David Lee
  • Total Lunar Eclipse is coming up on May 26th