• The Crescent Nebula, NGC 6888, in Cygnus
    • NGC 6888 in Cygnus, the Crescent Nebula
    Annotated image
  • NGC 6888, the Crescent Nebula, an emission nebula, and
  • the Soap Bubble, a planetary nebula, both in Cygnus.
  • Hover over the image for an annotated view.
  • Date:  7 November 2024 and 19 September 2025
  • FOV:  cropped to 90' × 60'; the angular size of NGC 6888 is about 18' × 12'
  • Rotation:  −0.006°
  • Telescope:  Stellarvue SVX102T + SFFR.74 reducer/flattener
  • (524.99mm, nominally 528mm, f/5.18)
  • Guiding:  ZWO ASI120MM mini mono guide camera,
  • Stellarvue F050G 50mm guide scope
  • Computer:  ASIair pro Raspberry Pi
  • Mount:  iOptron CEM40
  • Camera:  ZWO ASI6200MC Pro Cooled (-10°C) Color CMOS with gain 100
  • ZWO ASI071MC Pro Cooled (0°C) Color CMOS with gain 240
  • Pixel size:  3.76 μm ASI6200, 4.78 μm ASI071
  • Resolution:  1.478 arcsec/pixel (registered to ASI6200)
  • Filter:  Optolong UVIR cut, full light 7 November, 2024
  • Optolong L-Ultimate, dual narrow band 19 September, 2025
  • Frames:  thirty-five 240 second frames 7 November, 2024
  • thirty-nine 300 second frames 19 September, 2025
  • Stacking:  seventy-four frames using PixInsight
  • Total Time:  5 hours 35 minutes
  • Calibration:  20 flats, 20 dark flats, and 20 darks per session
  • Processing:  Pixinsight – SPCC, DBE, SPCC, BlurXT, NoiseXT → Linear
  • MStr, GHS, HST, PMath MStr + GHS + HST → stars
  • StarXT, MStr, GHS, HST, PMath MStr + GHS + HST → StarlessUVIR
  • StarXT, MStr, GHS, HST, PMath MStr + GHS + HST → StarlessLUlt
  • PMath ~(~StarlessUVIR*~StarlessLUlt) → Starless
  • PMath ~(~Stars*~Starless) → Blend, scale
  • Location:  Darling Hill Observatory in Vesper, NY