NGC 6888, The Crescent Nebula (Paul Kent)

Celestial hemisphere: Northern · Constellation: Cygnus (Cyg) · Contains: Crescent Nebula · IC 4996 · NGC 6888 · The star 28Cyg · The star 29Cyg · The star 34Cyg · The star 36Cyg

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NGC 6888, The Crescent Nebula

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NGC 6888, The Crescent Nebula

The Crescent Nebula is formed from strong stellar outflows from the central star. This star is a Wolf Rayet type, similar to the bubble nebula. It is a very massive, very hot star that has become unstable after its evolution on the main sequence. This is specifically WR136, which has a surface temp of 71,000K, over 10x hotter than the sun. This makes the star incredibly luminous, and supplies the energy required to ionise the gas it threw off. These shells of ionised gas are clearly seen surrounding the star. The electric blue colour here shows that the O3 emission is high compared to most other nebulae where it is usually much weaker than Ha. In contrast to the strong O3, the S2 emission is almost non -existant for the Crescent itself. It however is present in enough quantity in the surrounding 'field' gas to show through and a rusty colour.

Also present near the top centre is small, asymmetric Planetary Nebula, Abell 69.

In the upper left, the round nebula is SH2-104 from the Sharpless catalogue.

And that red star next to the crescent sticks out like a sore thumb. A bit of investigating shows it to be RS Cygni...not only a variable, but a Carbon star. These are very red due to carbon absorbing blue light.

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	Distinct awarded users	Total awarded images
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Distribution of subject types

This table shows the distribution of awards per subject type, compared to the popularity of images of that subject type.
	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
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Distribution of data sources

This table shows the distribution of awards per data source, compared to the popularity of images acquired from that data source.
	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
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Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

The “AstroBin Image of the Day and Top Picks”, or IOTD/TP, is a long-running system to promote beautiful, interesting, peculiar, or otherwise amazing astrophotographs, with a focus on technical excellence. Learn more.

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Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
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NGC 6888, The Crescent Nebula

NGC 6888, The Crescent Nebula

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NGC 6888, The Crescent Nebula

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