Friday, 5 February 2016

IC2118, the scary Witch Head

The Witch Head Nebula, hence nicknamed because of it's particular shape (upside-down on my sketch), is perhaps an example that in our universe sometimes a catastrophe can lead to something beautiful. The scientific community believes that this particular nebula is in fact the remnant of a supernova explosion, a cataclism in which a dying giant star blows its entire atmosphere into space. The cloud of gas and dust is all that remains of this event, and in this particular case so much time has passed that the gas has cooled down up to the point that it doesn't transmit light anymore on its own. However, that's without taking another nearby giant into account: Rigel, the bright blue left knee of Orion. You can't see it on my sketch because it was a bit outside the field of view of my binoculars (to the bottom left), but this enormous and very hot star illuminates the nebula so much that we can see it. Its shape also indicates a strong influence by the star, the stellar wind of which clearly ripples it, as if it'll never be allowed to rest in peace.

But is this the end? Has the old star just died without leaving anything else but its ashes spread across the galaxy? No! Recent research has shown that many parts of this gas cloud are contracting again under its own gravity and... that new stars are forming within it! So with time the Witch Head Nebula may become a bright stellar nursery, just like the Orion or Monkey Head nebulas of my previous posts. Isn't astronomy something beautiful?

This drawing has been high on my wish list for a long time but for some strange reason I've never really got to it. And when I did, sky conditions were always such as to impede any serious observation. But yesterday evening the sky was particularly transparent after the storm of the day before so I had another go at it. I had expected a very difficult observation because the nebula's incredibly faint and usually only visited by photographers who're able to capture it after many hours of exposure time. But yet, with some careful looking the patch around the central star appeared quite easily. And after some time and adapting myself fully to the dark, also the two "wings" revealed themselves, with the top-left one slightly brighter than the bottom-right one. Also the bright border, the one illuminated by Rigel, was quite pronounced, whereas the rest of the nebula faded in to the background towards the top-right.

All in all I'm quite pleased with this observation and I hope that you like it too. It's a very difficult object and given its enormous size a pair of big binos must be the perfect instrument for the job. As always I didn't want to make things too easy for my public so I've tried to create more or less the same challenge for you as it was for me behind the eyepieces of my binoculars. Enjoy!  

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