Crescent Nebula (NGC6888) close up in Hα/SII/OIII+rgb
Crescent Nebula revisited three years later with better equipment, better skies and some more skills on my side.
The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by William Herschel in 1792. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures. (Wikipedia)
That's the first image after this long period, in part due the COVID in part because the long integration time that I wanted and how short are these summer nights.
It was eleven nights with two rigs resulting on 75 hours of integration time. My longest integration time so far.
Imaging telescopes or lenses:Teleskop Service TS Photoline 107mm f/6.5 Super-Apo , Altair Astro RC250-TT 10" RC Truss Tube
Imaging cameras:ZWO ASI183MM-Cool , ZWO ASI1600MM-Cool
Mounts:Skywatcher EQ6R Pro , Mesu 200 Mk2
Guiding telescopes or lenses:Celestron OAG Deluxe , Teleskop Service TSOAG9 Off-Axis Guider
Guiding cameras:ZWO ASI174 Mini , ZWO ASI290 Mini
Focal reducers:Riccardi Reducer/Flattener 0.75x , Telescope-Service TS 2" Flattener
Software:Pleiades Astrophoto PixInsight , Seqence Generator Pro
Filters:Astrodon O-III 36mm - 5nm , Astrodon S-II 36mm - 5nm , Astrodon R Gen.2 E-series 36mm , Astrodon G Gen.2 E-series 36mm , Astrodon B Gen.2 E-series 36mm , Astrodon HA 36mm - 5nm , Astrodon L Gen.2 E-series 36mm
Accessory:ZWO EFW , MoonLite NiteCrawler WR30 , TALON6 R.O.R , MoonLite CSL 2.5" Focuser with High Res Stepper Motor
Dates:June 21, 2020 , June 22, 2020 , June 23, 2020 , June 29, 2020 , July 18, 2020
Astrodon B Gen.2 E-series 36mm: 50x120" (gain: 75.00) -20C bin 1x1
Astrodon G Gen.2 E-series 36mm: 50x120" (gain: 75.00) -20C bin 1x1
Astrodon HA 36mm - 5nm: 209x600" (gain: 200.00) -20C bin 1x1
Astrodon O-III 36mm - 5nm: 105x600" (gain: 183.00) -15C bin 1x1
Astrodon R Gen.2 E-series 36mm: 50x120" (gain: 75.00) -20C bin 1x1
Astrodon S-II 36mm - 5nm: 106x600" (gain: 183.00) -15C bin 1x1
Integration: 75.0 hours
Avg. Moon age: 7.92 days
Avg. Moon phase: 15.25%
Astrometry.net job: 3721258
RA center: 20h 12' 6"
DEC center: +38° 21' 0"
Pixel scale: 1.007 arcsec/pixel
Orientation: -89.431 degrees
Field radius: 0.408 degrees
Locations: AAS Montsec, Àger, Lleida, Spain
Data source: Own remote observatory
Remote source: Non-commercial independent facility