The Crescent Nebula
NGC 6888 • Wolf–Rayet bubble • Cygnus • 5000 light-years from Earth
🔭
Askar FRA400
📷
ZWO 2600MC Pro
🌃
Bortle 8
⏱️
25 hours
🗓️
July 2022
Overview
The Crescent Nebula, also known as NGC 6888, is a bright emission nebula located around 5000 light years from Earth in the constellation Cygnus. It formed when fast stellar winds from a hot, massive star collided with slower moving material ejected during an earlier stage of the star’s life, driving powerful shockwaves through the surrounding gas. The Crescent itself is embedded within much larger sweeping clouds of hydrogen, visible here in red, which frame the nebula and add to the sense of scale in wide field astrophotography.
Background
Although the Crescent Nebula itself is a bit small for my wide-angle 400mm Askar FRA400 telescope, it’s surrounded by nebulosity I figured would look good! My ZWO ASI 2600MC Pro camera has a fairly large sensor, and combined with the FRA400 gives a good field of view.
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Explore the field
Objects in this field 33 objects
33 objects
No matching objects.
- Crescent NebulaNGC 6888
- HII regionAlso catalogued as C 27 · LBN 203 · Sh2-105
- Soap Bubble NebulaJu 1
- Planetary nebulaAlso catalogued as PN G075.5+01.7
- P Cyg
- Variable starAlso catalogued as 34 Cyg · HR 7763 · HD 193237 · HIP 100044
- B2pe · S Dor variable 3–6 mag
- RS Cyg
- Variable starAlso catalogued as HD 192443 · HIP 99653
- C5II · Semiregular variable 6.5–9.5 mag, period 417 d · Double (BLL 47AB) 131.7″ at 354°, companion 7.15 mag
- ASCC 111
- Open cluster
- HR 7784
- Double starAlso catalogued as HD 193702 · HIP 100268
- A1V · Double (STF 2668AB,C) 3.7″ at 280°, companion 8.49 mag
- Gulliver 31
- Open cluster
- Dolidze 5
- Open cluster
- UBC 1104
- Open cluster
- Basel 6
- Open cluster
- Gulliver 23
- Open cluster
- Be 86
- Open cluster
- VDB 130
- Open cluster
- Dolidze 39
- Open cluster
- Feibelman 1
- Open cluster
- Gulliver 42
- Open cluster
- LBN 236
- HII region
- LDN 886
- Dark nebula
- LBN 193
- HII region
- LBN 208
- HII region
- LBN 206
- HII region
- vdB 130
- Reflection nebula
- LBN 215
- HII region
- LBN 209
- HII region
- LBN 223
- HII region
- B 343
- Dark nebulaAlso catalogued as LDN 880
- NGC 6874
- Stellar association
- B 344
- Dark nebula
- LDN 877
- Dark nebula
- LDN 881
- Dark nebula
- LDN 879
- Dark nebula
- LDN 883
- Dark nebula
- LDN 882
- Dark nebula
About the labels and credits
Positions and outlines are calculated from a plate solution of this photograph. Outlines are catalogue guides and may not follow every visible filament. Additional catalogue objects may be faint or indistinct in this exposure.
Plate solving and annotation data: SkySolver, by Dominik Sito. Stars: Gaia DR3 and Hipparcos (ESA). Deep-sky data: OpenNGC © Mattia Verga (CC BY-SA 4.0), SIMBAD and VizieR (CDS). Names: Wikipedia (CC BY-SA 4.0) and IAU WGSN. Catalogue overlay adaptations, including styling and selected display names, are shared under CC BY-SA 4.0. Photograph © Lee Pullen.
Science
I made a close crop to show the Crescent itself more clearly. Lightroom’s Enhance function allowed me to upscale the resolution quite effectively (and of a higher quality than I got with Topaz Gigapixel AI). The result is better than I expected. The outer shell of Oxygen, shown in blue, is quite evident:
When editing the full image, I noticed a strange tiny circular object. At first I thought it was an artifact left over from the star removal stage during processing, but it didn’t look quite right for that. I did some research and found that it’s actually the Soap Bubble Nebula, a planetary nebula. It was discovered in 2008 by Dave Jurasevich, using a 160mm refractor. It’s quite amazing that with modern camera sensors and processing techniques it can be imaged from the centre of a city using a small aperture (72mm) refractor. Find the Soap Bubble in the interactive photograph to see where it sits below the Crescent Nebula.
Imaging and equipment
- Total exposure
- 25 hours
- Dates captured
- July 2022
- Location and sky
- Bristol, UK (Bortle 8)
Equipment and software
- Telescope
- Askar FRA400
- Camera
- ZWO ASI 2600MC Pro
- Mount
- Orion Sirius EQ-G
- Guiding
- WO 32mm + ZWO ASI 120MM Mini
- Control
- ASIAIR Plus
- Software
- PixInsight, Lightroom
- Image by
- Lee Pullen
Exposure by filter
Optolong L-eXtreme
- Channels
- Hα / OIII
- Subframes
- 750 × 2 minutes
- Integration
- 25 hours
View subframe and stack
Single subframe and integrated stack, both with a simple stretch applied.
Reviews and where to buy
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See my full astrophotography kit →
Telescope: Askar FRA400
Read my review
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Buy from High Point Scientific
Camera: ZWO ASI 2600MC Pro
Read my review
Buy from Astroshop.eu
Buy from High Point Scientific
Guidescope: William Optics 32mm Slide-Base Uniguide
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Buy from Astroshop.eu
Buy from High Point Scientific
Guidecam: ZWO ASI 120MM Mini
Read my review
Buy from Astroshop.eu
Buy from High Point Scientific
Control: ASIAIR Plus
Read my review
Buy from Astroshop.eu
Buy from High Point Scientific
Filter: Optolong L-eXtreme
Read my review
Buy fromAstroshop.eu
Buy from High Point Scientific
Processing
This was relatively straightforward, but I did try using Generalised Hyperbolic Stretch to take the data to non-linear; and NoiseXTerminator for noise reduction. Also, I liked the strong red colours in the image, so didn’t split the channels to create any kind of pseudo-Mono style picture.
It took a bit of teasing to get the faint nebulosity out. Use the slider below to compare a single sub-frame to the final, edited image. These slider comparisons make the whole process seem like magic!
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Great to see some new content (I need to catch up on your site) – you actually inspired me to get my stuff up on a WordPress site.
I’ve been using StarXTerminator and NoiseXTerminator a bit now .. so much so I’m re-doing some of my older content with newer processes.
I’m impressed with your integration times! I’m still sub 4-5 hours on most targets.. I plan to beef most up to 10-15+ . I’m loving the new 16bit sensors and how sensitive they are.
Like you, I thought the Soap Bubble was a reflection, and spent hours trying to clone it out … need to reprocess again with it back in haha!
I couldn’t get my head around GHS, I’m still lazy.. most of my imaging is targets using the L-Extreme, so I’m using EZ Stretch and then extracting/manipulating and a channel combination as fake SHO. (although I have a SII/OIII Dualband filter on back order..)
Take care, clear skies!
Luke
Thanks for the comment Luke! Give GHS a good go, it can give great results 🙂