The Crescent Nebula and Interstellar Gas Clouds

The Crescent Nebula (NGC 6888) is a cosmic bubble nebula 5,000 light years away blown by winds from its central dead star. An integration of Hydrogen-α and Oxygen III data that I collected during the short and bright nights of June this year (2019). 186 minutes (62 x 3 mins) total integration time. The final image was processed with PixInsight's StarMask and MLT to reduce the stars for a dramatic view of the cosmic nebula in a sea of cosmic gas clouds.

Tech Card

Date / Location

29th June 2019, 30th June 2019 & 2nd July 2019, Bedworth, GMT+0, United Kingdom, Bortle Class 5 ~SGM: 19.57 mag./arc sec2

Equipment

Camera: ZWO ASI 1600MM-PRO USB 3.0 Mono (Type CMOS)

Sensor Cooling Temperature: -15C

Filters: 1.25" 5nm Astrodon Ha, 1.25" 3nm Astrodon OIII

Imaging Telescope: Takahashi FS-60CB

Correcting Lens: Takahashi Reducer 0.72x (composite focal length at 264mm and focal ratio at f/4.9)

Mount: iOptron CEM25EC

Image Quality

12Bit ADC (FITS)

Exposure time per image / number of composities and sensitivity

62 x 120" Ha subs (Gain 200, Offset 50/16, Binning 2x2)

44 x 120" OIII subs (Gain 200, Offset 50, Binning 2x2)

Total Integration Time

3hrs 32mins

Calibration Frames

25 Darks, 20/20 Flats for Ha/OIII

Software

PixInsight 1.8 Core

Photoshop

SharpCap