Hemisphere:  Northern  ·  Constellation: Cepheus (Cep)  ·  Contains:  Sh2-129

Image of the day 06/19/2020

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SH2-129 and OU4, 


            Thomas Richter
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SH2-129 and OU4

Acquisition type: Electronically-Assisted Astronomy (EAA, e.g. based on a live video feed)

Technical card

Imaging telescopes or lenses: Skywatcher Esprit 80 ED Triplet Super Apo

Imaging cameras: ZWO ASI 183 MM PRO

Mounts: SkyWatcher NEQ6 Pro Goto

Guiding telescopes or lenses: Skywatcher Esprit 80 ED Triplet Super Apo

Guiding cameras: Astrolumina Alccd5L-IIc

Focal reducers: Skywatcher Field flattener for Esprit 80mm

Software: PhotoShop CS5  ·  PHD2 Guiding  ·  FitsWork 4  ·  DeepSky Stacker Deep Sky Stacker 3.3.4  ·  CCDCiel

Filters: Baader Planetarium O3 1.25" 8.5nm  ·  Baader R 1.25'' CCD Filter  ·  Baader B 1.25'' CCD Filter  ·  Baader G 1.25'' CCD Filter  ·  Baader Ha 1.25" 7nm

Accessory: TSOptics TS Off Axis Guider - 9mm

Dates:May 17, 2020May 18, 2020May 21, 2020May 25, 2020

Baader B 1.25'' CCD Filter: 14x300" (gain: 53.00) -20C bin 1x1
Baader G 1.25'' CCD Filter: 14x300" (gain: 53.00) -20C bin 1x1
Baader Ha 1.25" 7nm: 21x600" (gain: 200.00) -20C bin 1x1
Baader Planetarium O3 1.25" 8.5nm: 48x600" (gain: 200.00) -20C bin 1x1
Baader R 1.25'' CCD Filter: 14x300" (gain: 53.00) -20C bin 1x1

Integration: 15.0 hours

Darks: ~37

Flats: ~25

Flat darks: ~100

Avg. Moon age: 20.36 days

Avg. Moon phase: 12.17%

Astrometry.net job: 3584838

RA center: 21h 11' 49"

DEC center: +59° 57' 38"

Pixel scale: 1.199 arcsec/pixel

Orientation: -90.030 degrees

Field radius: 1.085 degrees

Resolution: 5412x3625

Locations: Nürnberg, Nürnberg, Bayern, Germany

Data source: Backyard


It was a really hard object. OU4 is extremely faint ! There was almost nothing to be seen in the single frames. Only after stacking I could see a faint nebula. So the image processing was very difficult.

Object description: (https://apod.nasa.gov):

A mysterious, squid-like apparition, this nebula is very faint, but also very large in planet Earth's sky. In the mosaic image, composed with narrowband data from the 2.5 meter Isaac Newton Telescope, it spans some 2.5 full moons toward the constellation Cepheus. Recently discovered by French astro-imager Nicolas Outters, the remarkable nebula's bipolar shape and emission are consistent with it being a planetary nebula, the gaseous shroud of a dying sun-like star, but its actual distance and origin are unknown. A new investigation suggests Ou4 really lies within the emission region SH2-129 some 2,300 light-years away. Consistent with that scenario, the cosmic squid would represent a spectacular outflow of material driven by a triple system of hot, massive stars, cataloged as HR8119, seen near the center of the nebula. If so, this truly giant squid nebula would physically be nearly 50 light-years across.