NGC 6960: Western Veil Nebula / Witch's Broom Nebula
Date: 22/10/08 Time: 2345hrs Location: Sunningwell Temperature: 3ēC Relative Humidity: 61%
Camera: Nikon D80 Scope: William Optics Z66 Apo Doublet at prime focus Mount: piggy-backed on Meade LX90 in equatorial mode Filter: Astronomik CLS (LPF broadband filter) Exposures: 180+360+(3x600) seconds ISO: 1600 F ratio: 5.9 Guidance: Autoguided
The Veil Nebula is a supernova remnant, some 5000 years old, and approximately 2000 light years away (references vary between 1400 and 2600 so I opted for the median value!) in the constellation Cygnus. It covers an area 3° square just forward of the swan's left wing. The areas of nebulosity are divided into the Eastern Veil - outside the picture's top left corner, Pickering's Wedge (the faint 'V' shaped nebulosity in the top left) and the Western Veil, which flows across the bright star 52 Cygni in the centre of the photograph.
I have not had an opportunity for astrophotography between March this year and now! Even the evening which I took this picture (in the middle of a working week) was cut short in the middle of the 6th exposure by cloud cover bringing an end to the session at 1am. This is the reason for this photo's main problem - underexposure. All the best pictures on the web have been at least 1 hour's worth of exposure, optimally two. This picture is the sum of 5 exposures amounting to only 39 minutes of exposure time. In spite of this however, you can still see the fine filaments of red (hydrogen) and blue (oxygen) which represent layers of ionised gas seen edge-on, impelled outward from the original exploding star. The sharp-eyed among you will also see a satellite trail which was present on the 360 second exposure but I was damned if I was going to exclude those precious 6 minutes just because of a pesky piece of space-junk. The exposures were combined in MaximDL, the combined master had black and white point setting, midtone enhancement and noise ninja filtering carried out in Photoshop as usual.
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