Variable Wolf-Rayet star in constellation “Cygnus”
Project #13
WR 134 (HD 191765) is a variable Wolf-Rayet star located around 6.000 light years away from Earth in the constellation of Cygnus, surrounded by a faint bubble nebula blown by the intense radiation and fast wind from the star. It is five times the radius of the sun, but due to a temperature over 63.000 K it is 400.000 times as luminous as the Sun.
WR 134 was one of three stars in Cygnus observed in 1867 to have unusual spectra consisting of intense emission lines rather than the more normal continuum and absorption lines. These were the first members of the class of stars that came to be called Wolf-Rayet stars (WR stars) after Charles Wolf and Georges Rayet who discovered their unusual appearance. It is a member of the nitrogen sequence of WR stars, while the other two (WR 135 and WR 137) are both members of the carbon sequence that also have OB companions. (Source: Wikipedia)
WR134 – Project Publications
Image Publications
Please find all project-related images for this revision below.
POST-Processing approach
Please take note, that – for this revision – I took the same data as I used for WR134 Rev.1. Here are the steps I took (this time);
Astro Pixelprocessor (APP)
- calibration, registration and stacking of RGB data
- calibration, registration and stacking of dual-narrowband data
- separation of dual-narrowband data (HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More)
- separation of dual-narrowband data (OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More)
- registration of RGB-, Halpha- and OIII-integration frames
- dynamic batch crop of registered integration frames
GraXpert (GXP)
- background extraction; one version with (classic/manual) RBF algorithm, one time with the new AI algorithm
PixInsight (PI)
RGB Data
- ImageSolver for RGB integration frame (for SPCC)
- SPCC for RGB integration frame
- BXT for RGB integration frame
- SXT for RGB integration frame
- NXT for RGB/starless integration frame
Narrowband Data
- BXT for HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More integration frame
- SXT for HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More integration frame
- BXT for OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More integration frame
- SXT for OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More integration frame
I did not run NXT on the HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More/starless and OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More/starless images as I was not really satisfied with the results (clipping). I took the decision to play around with Photoshops’ Camera RAW filter later on.
Stretching
- GHS for HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More/starless integration frame
- GHS for OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More/starless integration frame
- GHS for RGB/starless integration frame
- GHS for RGB/stars integration frame
- export of stretched integration files to 16bit .tif files
Photoshop (PS)
- repairing of stretched HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More/starless integration frame + var. enhancements
- repairing of stretched OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More/starless integration frame + var. enhancements
- HLVG filter on both RGB and RGB/starless
- setting blackpoint on RGB frame
- integration, boosting and enhancement of both HalphaH-alpha (Hα) is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy level. H-alpha has applications in astronomy where its emission can be observed from emission nebulae and from features in the Sun's atmosphere, including solar prominences and the chromosphere. (Source: Wikipedia) More/starless and OIIIIn astronomy, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green-turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of [O III] are much less pronounced. (Source: Wikipedia) More/starless
- integration and enhancement of RGB/stars
- combination of all layers
- final enhancements with Camera RAW (e.g. histogram adjustments, tweaks on colors, etc.)
Check the following comparison to see the differences between Rev.1 and Rev.2 – I know they’re not rotated equally, but I think it shows the outcome quite good;
WR134 – Project Details
Please find all project-related details for this revision below.
| Astrobin Link | WR134 (Rev.1) with OSC+Dual Narrowband (HO) |
| Astronomical Object | WR134 / HD 191765 |
| Distance to Earth | 1.750pc (= 5.708ly) |
| Size / Diameter | 5,23R (solar radius) |
| Date(s) of Photography | June & July 2023 |
| Exposure Details | Dual Narrowband: 168 x 600″ (28h 0min) Clearglass: 105 x 180″ (5h 15min) Total: 33h 15min |
| Calibration | BIAS / DarksA "dark frame" is shot in the dark (so e.g. covering your camera) with the same exposure as your light frames (e.g. 180sec, 300sec, 600sec) and contains the dark signal (and the so called "thermal noise", if not -properly- cooled). Those frames allow you to remove the sensor noise from your light frames, but also to tackle pixel errors (hot and cold pixels). The combination/stack of multiple dark frames is called a "Master Dark". More / FlatsA "flat frame" is shot against a bright surface and contains vignetting and all the "bad" things (e.g. dust particles) that block/disturb your light train. The combination/stack of multiple flat frames is called a "Master Flat". More / DarkFlatsA "darkflat frame" is basically the same as a flat frame with the same exposure and camera settings, but shot in the dark. They are used to calibrate the flat frames. The combination/stack of multiple darkflat frames is called a "Master DarkFlat". More |
| Equipment | Mount: Skywatcher EQ6-R PRO (the old w/o USB-interface) Telescope: Skywatcher 200PDS Newton (200mm/1000mm, f/5) Camera: Touptek DeepSky Pro 2600c (Gain: 100, Offset: 100) Clearglass Filter: Baader Clearglass 2″ Dual Narrowband Filter: Optolong L-eXtreme 2″ Corrector: Pál Gyulai GPU Komakorrektor Guiding(Auto-)Guiding is essential in astrophotography, as an un-guided mount/telescope will produce blurry images as the stars / the deepsky object will drift away. This is heavily dependent on the exposure time, so for long exposures you want to make sure to have a perfectly set up auto-guiding. More: ZWO ASI120MM + 50mm Helica |
| Software | Observatory Automation: Sequence Generator Pro Guiding(Auto-)Guiding is essential in astrophotography, as an un-guided mount/telescope will produce blurry images as the stars / the deepsky object will drift away. This is heavily dependent on the exposure time, so for long exposures you want to make sure to have a perfectly set up auto-guiding. More: PHD Post-Processing: Astro Pixel Processor + PixInsight + Photoshop |
