Astronomy Cafe – Mar 21, 2022

Posted by as Astro Cafe

Video transcript of the meeting

Deborah Lokhost presented to us about the Dragonfly Telephoto Array. She is an Instrument Science Research Associate at the NRC Herzberg Astronomy and Astrophysics Research Centre in Victoria, BC. During her PhD in the Department of Astronomy and Astrophysics at the University of Toronto, she worked with the Dragonfly Telephoto Array to observe and study galaxies. She designed an upgrade to Dragonfly and built a pathfinder telescope based on this design which she then used to study gas in the surroundings of galaxies. She is currently leading the construction of a full-scale upgrade to the telescope which has the ultimate goal of imaging gas in the “cosmic web” of dark matter.

Dragonfly Telephoto Array

  • Reasons for Dragonfly
    • Large galaxies with low luminosity (surface brightness)
    • Light scattering is the main problem
    • Reflecting telescopes don’t help, since they scatter light
    • Refractors have a limit in size
  • Design
    • Canon using nano coatings to reduce light scatter for their long telephoto lenses
    • Using 48 Canon EF 400mm f/2.8L – split between two Paramounts/observatories
    • Mexico Skies Observatory – site
    • Astroplanner – mission planning and execution
    • Been in operation for 6 years
    • Comparison between Dragonfly and Sloan Digital Sky Survey
    • Diffraction Limited SBIG CCD cameras
    • Intel stick computers talk to a master computer for data collection
    • Filter 1/2 G and 1/2 R (Sloan clone)
  • Science
    • Main target is galaxies
    • What is Dark Matter? 90% of the Milky Way is Dark Matter
    • Dark Matter first detected by Vera Rubin
    • Ultra Diffuse Galaxies – new discovery by Dragonfly team
    • Looking for Globular Clusters in these ultra diffuse galaxies
    • First field images – Coma Berenice cluster of galaxies
    • NGC 1052 diffuse galaxies – very little Dark Matter – unusual!
    • Modified Newtonian Galaxy – alternate theory to Dark Matter
  • What about outside galaxies? – Deborah’s main study
    • Detecting faint gas emissions using ultra-narrowband filters
    • Simulated Ha observations from EAGLE cosmological simulation that should be possible using Dragonfly
    • Mounting the ultra-narrowband filters in front of the lenses would improve the result, and tilting the filter improves performance
    • Discovered a new Ha shell around M81/M82
    • 0.8nm filters will be used on new array
    • 30 new lenses to start with for testing and fine tuning

Members Reports & Presentations

  • Edmonton astrophotos – Dave Robinson
    • NGC 4565 Needle Galaxy with many tiny galaxies in the field – Denis Boucher
    • Comet C/2020 L3 (Atlas) – Alister Ling
    • NGC 281 emission nebula – Tom Owen
  • Galactic Atmospheres gallery – Jim Hesser
  • SIGs – David Lee
    • Astrophotography – Wed
    • Makers – Thu – using Arduino microprocessors
  • Gov’t of Canada Citizen Science Portal – David Lee
  • James Web Space Telescope update – Chris Gainor
    • Pointing, focusing and alignment of the mirrors is complete
    • Now aligning the various instruments and guidance sensors
  • “Not Yet Imagined” History of Hubble – printed book now available from Chris Gainor (email)
  • Next week’s Café on March 28 – Jeff Pivnick
    • Invited a guest speaker. Vickie Siegel of Stone Aerospace who will be speaking about exploration using remote autonomous vehicles.
    • Crybots and AUVs intended for exploring Europa’s subsurface seas
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