• NGC 7331 and Stephan's Quintet in Pegasus
    • Stephan's Quintet (Arp 319)
    Annotated image
  • Arp 319, or Stephan's Quintet, is a visual group of five galaxies.
  • The brightest galaxy, NGC 7320, is much closer to us and is not
  • a gravitational member of the group.  The other four galaxies,
  • NGC 7318a, NGC 7318b, NGC 7319, and NGC 7320, are
  • gravitationally bound.  The NGC 7318 galactic pair
  • is located approximately 280 Mly from us.
  • Hover over the picture for an annotated version
  • Date:  29 September 2024
  • FOV:  cropped to 18' × 12'; the long axis of Stephan's Quintet is about 5'
  • Telescope:  Orion 180mm Mak-Cass (2510mm, f/14, nominally 2700mm, f/15)
  • Guiding:  ZWO ASI120MM mini mono guide camera,
  • SVBony SV165 Mini 40mm f/4 guide scope
  • Computer:  ASIair pro Raspberry Pi
  • Mount:  iOptron CEM40
  • Camera:  ZWO ASI6200MC Pro Cooled (-10°C) Color CMOS with gain 300
  • Pixel size:  4.78 μm
  • Resolution:  0.393 arcsec/pixel
  • Filter:  Optolong UV-IR cut filter
  • Stacking:  one hundred and one 240 second frames using Pixinsight
  • Calibration frames:  20 dark, 20 flat, 20 dark flat for each session
  • Total Time:  6 hours 44 minutes
  • Processing:  Pixinsight – SPPC, DBE, SPCC, BlurXT, NoiseXT, DynCrop → Linear
  • MStr, GHS, HST, PMath MStr + GHS + HST → Stars, Sat,
  • StarXT, MStr, GHS, HST, PMath MStr + GHS + HST → Starless,
  • HDR8464PhLm, Sat, PMath ~(~Stars*~Starless) → Blend, scale
  • Location:  Crystal Lake near Redwood, NY