Jul 17 2012 By David Moulton – North Wales Astronomy Society

Crescent Nebula

Without doubt it has been a difficult summer for Astronomy, not only the light nights, but the dreadful weather has put the handbrake on my pursuit of Astrophotography.

I did however manage just one night under the stars in the middle of June during a gap in the fronts coming in for m the Atlantic. The skies cleared that evening and stayed clear until dawn so I took full advantage and was up imaging until the dawn chorus.

The target for the night was a wide field view of NGC 6888 common name The Crescent Nebula. This object is located in The heart of the milky way in the constellation of Cygnus, I imaged this target in Natural colour several years ago now in close up (see image), but I have also been aware that the area is worth looking at in wide field as there is plenty going on. This wide field image was taken using my ED80 Refractor telescope using Narrowband filters in a cooled QSI 583 Astro camera. The resulting data on the night totalled 2.5hrs of exposure and has been colour mapped to the Hubble palette colours to produce the image

The Crescent is estimated to be 5000 light years distant and is an estimated 400,000 years old. The Nebula itself has been formed from material expelled from a dying Red Giant star; this material has fallen under the spell of the stellar wind emitting from a neighbouring Wolf- Rayet star, this interaction has resulted in the dramatic shock fronts seen in the Crescent Nebula. The wide field view does however illustrate just how active whole region is, showing large swirls of emission nebulosity that are present in the area.

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