Sharpless Sh2-206, also listed as New General Catalogue (NGC) 1491, is commonly called the Fossil Footprint Nebula.  The portion of the nebula in this image is the “heel” of the footprint; the toes are much dimmer and not in this image.  To me, the most obvious feature of the nebula is the bright scribble that looks like a signature.  So I’d call it the Signature Nebula.  What do you think?

Sh2-206 is an H II region emission nebula, a region of ionized atomic hydrogen.  The H II regions in the Sharpless 2 catalog were “defined not only in terms of the ionized gas but also in terms of the hot stars which are responsible for the ionization.”

Sh2-206 seems to be associated with one bright star: BD +50 886, which is the bright star just under the “signature” in the nebula.  This star is a type O4 star, young, massive, and hot.  It is approximately 9590 +/- 1000 light years away, which is close to the 9850 light years +/- 2000 light years distance for the nebula itself.  BD +50 886 is considered a runaway star with a 2D peculiar velocity (velocity relative to its environment) of 30.5 +/- 3.9 km/sec.  Not only is it ionizing the gas around it to make this nebula, but the “signature” in the nebula may be a bow shock due to the radiation pressure from the star on the local gas and the relative motion of the star and the local gas.

Sh2-206 is located in the Milky Way, approximately 9850 light years away.  The nebula in this image is 25 arc minutes across, so the nebula in this image is approximately 71 light years across.  

In this image, the stars came from images using red (0.47 hours), green (0.29 hours), and blue (0.3 hours) filters, and the nebula came from images using Sulfer ii (6.5 hours of data mapped to red), Hydrogen alpha (1.5 hours of data mapped to green) and Oxygen iii (7.67 hours of data mapped to blue) filters, the standard SHO mapping.  The nebula was processed separately from the stars to maximally enhance it.

Camera geek info:

• William Optics Pleiades 111 telescope
• ZWO 2” Electronic Filter Wheel
• Antila SHO and RGB filters
• Blue Fireball 360° Camera Angle Adjuster/Rotator
• ZWO ASI183MM-Pro-Mono camera
• William Optics Uniguide 32MM F/3.75
• ZWO ASI220MM-mini
• ZWO ASiair Plus
• iOptron CEM40
• Friendswood, Texas Bortle 7-8 suburban skies

Frames:

• December 30, 2025
  • 9 600 second Gain 150 Ha lights
  • 30 0.5 second Gain 150 Ha flats
• December 31, 2025
  • 15 600 second Gain 150 Oiii lights
  • 30 0.2 second Gain 150 Oiii flats
• January 2, 2026
  • 15 600 second Gain 150 Sii lights
  • 30 0.5 second Gain 150 Sii flats
• January 3, 2026
  • 15 600 second Gain 150 Sii lights
  • 30 0.5 second Gain 150 Sii flats
• January 31, 2026
  • 9 600 second Gain 150 Oiii lights
  • 30 0.2 second Gain 150 Oiii flats
• February 6, 2026
  • 9 600 second Gain 150 Sii lights
  • 30 0.5 second Gain 150 Sii flats
• February 21, 2026
  • 84 20 second Gain 150 Red lights
  • 30 0.02 second Gain 150 Red flats
  • 53 20 second Gain 150 Green lights
  • 30 0.01 second Gain 150 Green flats
  • 54 20 second Gain 150 Blue lights
  • 30 0.01 second Gain 150 Blue flats
• February 28, 2026
  • 2 600 second Gain 150 Oiii lights
  • 30 0.2 second Gain 150 Oiii flats
• March 12, 2026
  • 8 600 second Gain 150 Oiii lights
  • 30 0.2 second Gain 150 Oiii flats
• March 13, 2026
  • 12 600 second Gain 150 Oiii lights
  • 30 0.2 second Gain 150 Oiii flats
• 30 Flat Darks matching flat durations from library
• 30 Darks matching light durations from library

Processing geek info:

• PixInsight
• BlurXterminator
• NoiseXterminator
• StarXTerminator
• Narrowband Normalization
• Image Blend