Measure Venus’s Phases

Note: use a mouse instead of a trackpad or touchscreen to limit frustration while using Afterglow. 

Click “Next” above to see the step-by-step instructions.

Alternate Format: Video Instructions

Alternate Format: Written Instructions

  1. You will use archival data for this. If you have your own Venus image you will also use that one.
    • Open each image in Afterglow using the “Open Files” icon in the upper left.
      • File path: Sample/Astro 101 Lab/Lab 3 – Galilean Revolution/Venus/[filename].fits
  2. Measure the the illuminated angular distance  and the angular diameter on each Venus image.
    • Open each image and set the display to “Bright Target.”
    • Open the plotter tab
    • For each image take two measurements, and record them in the Skynet 3 Observation Report.
      • Illuminated Angular Distance
      • Angular Diameter
      • The angular diameter is the distance from tip to tip of the crescent Venus. The illuminated angular distance is the distance across the widest part of the crescent, perpendicular to the angular diameter.
      • Illuminated angular distances will always be smaller than angular diameters.
    • For each image, calculate the phase:
      • The phase is the illuminated angular distance divided by the angular diameter. It will be between 0 and 1.
      • LaTeX: phase=\frac{illuminated\: angular\: distance}{angular\: diameter}

Media Attributions

  • lab3_proc_c_01

License

Skynet and Afterglow User Manual - Astro 100 - Enevoldsen Copyright © by Alice Enevoldsen. All Rights Reserved.

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