• Messier 101 in Ursa Major
    • M101
    Annotated
  • NGC 5457 or Messier 101 in Ursa Major.
  • Twice the size of our own Milky Way,
  • the Pinwheel Galaxy is 23 mly away.
  • Hover over the image for an annotated view.
  • Date:  26 May 2025
  • FOV:  cropped to 60' × 40'; the angular size of M101 is about 29 × 27'
  • Telescope:  Stellarvue SVX102T + SFFX-1 (714mm, f/7)
  • Guiding:  ZWO ASI120MM mini mono guide camera,
  • Stellarvue F050G 50mm guide scope
  • Computer:  ASIair pro Raspberry Pi
  • Mount:  ZWO AM5
  • Camera:  ZWO ASI6200MC Pro APS/c mode cooled (-10°C)
  • Color CMOS with gain 100
  • Filter:  Optolong UV/IR cut
  • Stacking:  eighty-three 240 second frames using PixInsight
  • Calibration frames:  20 dark, 20 flat, 20 dark flat
  • Total Time:  5 hours 32 minutes
  • Processing:  Pixinsight – SPCC, DBE, SPCC, BlurXT, NoiseXT → Linear
  • HTS, GHS, MStr, PixelMath MStr + GHS + HST → Stars,
  • Linear, StarXT, HTS, GHS, MStr,
  • PixelMath MStr + GHS + HST → Starless, HDRMST654PhLm
  • PixelMath ~(~Starless*~Stars) → Blend, Sat, DynCrop/Scale
  • Location:  Stony Creek State Boat Launch near Henderson, NY