Drawing HII Regions - acnelson12/PP4 GitHub Wiki

PP4 currently just uses plain red for HII regions.

Calculating a Better HII Color

Visible hydrogen emissions come from the first four wavelengths of the Balmer Series.

  • Hydrogen alpha: 656 nm - FF0000
  • Hydrogen beta: 486 nm - 55DDFF
  • Hydrogen gamma: 434 nm - 0000FF
  • Hydrogen delta: 410 nm - 5F5FD3

Creating the color of glowing hydrogen is now a matter of finding the relative intensities of each wavelength.

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/hydspec.html

  • 300p H Alpha
  • 080p H Beta
  • 030p H Gamma
  • 015p H Delta
  • 425p total

The relative colors for mixing are then:

  • 180r 0g 0b
  • 16r 42g 48b
  • 0r 0g 18b
  • 3r 3g 7b

This yields 199r 45g 73b. Maximizing the intensity gives 255r 58g 94b or FF3A5E.

http://spacemandan.net/astronomy/Deep_Space/Eagle_Nebula/In_True_Color-med.jpg

Comparing this color to the picture above, the color seems reasonably accurate.