Derby and District Astronomical Society

Caldwell 33 (NGC 6992/NGC 6995)
The Eastern Veil Nebula

RA 20h 56m 24s  Dec +31d 43m 00s

NGC 6979
The Central Veil Nebula

RA 20h 51m 00s  Dec +32d 09m 00s

Caldwell 34 (NGC 6960)
The Western Veil Nebula

RA 20h 45m 42s  Dec +30d 43m 00s

Supernova Remnants in Cygnus

[Caldwell Index]


Adrian Brown captured this image of the Eastern Veil Nebula (Caldwell 33/NGC 6992) in July 2008. The data for this image consists of nine 20 minute exposures with an Astronomik 6nm Hydrogen-Alpha filter and six 20 minute exposures with an Astronomik 13nm Oxygen-III filter. Adrian used a Skywatcher 80ED refractor, William Optics 0.8x focal reducer, and an Atik ATK16HR CCD camera. Maxim DL was used to calibrate (bias and flat-field) and stack the raw images. The stacked hydrogen-alpha and oxygen-III images were then processed in Photoshop using Levels and Curves. A light Gaussian Blur filter was used to smooth noise in the dimmest parts of the images. To create the colour image Adrian used Adobe Photoshop to assign the hydrogen-alpha data to the red channel, the oxygen III data to the green channel and the blue channel was created from the oxygen III data + 20% of the hydrogen-alpha data to simulate the hydrogen-beta line. Here is a link which documents the reasoning behind this technique for creating tri-colour images from halpha and [OIII] data sets: http://www.narrowbandimaging.com/synthetic_rgb_page.htm





This image of the Western Veil Nebula (Caldwell 34/NGC 6960) was taken by Adrian Brown during the summer of 2007. It is a false colour image, created from four 30 minute exposures via a 6nm hydrogen-alpha filter and one 30 minute exposure via a 13nm Oxygen-III filter. The hydrogen-alpha image is assigned to the red channel and the oxygen III image is assigned to the blue channel. A synthetic green channel was created in Photoshop using the Astronomy Tools plug-in. An ATK16HR CCD camera and Skywatcher 80EDPro refractor were used to capture the exposures. The bright star at the centre of the image is 52 Cygni.





Adrian Brown took the following image of the Veil Nebula in Cygnus on the night of the 3rd-4th September 2005. The imaging equipment was a Canon 300D DSLR camera with a 200mm focal length lens and a Hutech LPS light pollution filter, piggy-backed on top of a Celestron C11 SCT which was used to autoguide the mount. The raw exposures were taken at ISO 400 to help suppress the buildup of noise. The image is a composite of six 9 minute exposures. The images were stacked and dark frame calibrated with Maxim DL 4.11 and then further processing was done in Adobe Photoshop via the Curves and Levels tools. Adrian also used a Photoshop plugin called GradientXTerminator to fix light pollution gradients in the picture's backgrounds. The leftmost (eastern) filament of nebulosity is Caldwell 33 (NGC 6992/NGC 6995), the central patch is NGC 6979, while the rightmost (western) filament is Caldwell 34 (NGC 6960). The bright star superimposed on the Western Veil is 52 Cygni.




Adrian Brown produced the following image of the eastern section of the Veil Nebula (Caldwell 33 - NGC 6992/NGC 6995) in Cygnus in July 2005. He used a Skywatcher EvoStar 80ED refractor with an ATK-2HS camera, and an Orion SkyGlow light pollution filter. The image is a stacked composite of six, ten minute exposures.

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