2023: Missouri – Widefield view of NGC 6888, SH2-101, and WR 134

In the summer months, we can capture the wonderful nebulae region in the constellation Cygnus. In this frame, the beautiful Crescent and Tulip nebulae and the material from the hot star WR 134 with their surroundings can be seen in full glory. The image is a combination of Ha data and Oiii data.

Imaged on September 9th, 2023. A Wide field view showing the NGC 6888, SH2-101, and WR 134. This spring and summer have been challenging, with an abundance of clouds during prime imaging time and wildfire smoke, which blanketed the night skies. I welcome cooler temps and hopefully clearer skies in October.

This wide-field view includes emission nebulae Crescent (upper right area) and Tulip (lower left area), including a faint blue nebula around the Wolf-Rayet star WR-134 (above left center frame of the image).

A single frame is exposed at 300 seconds.

About each object

(NGC 6888) is a 25 light-year-wide emission nebula, that is 5000 light years from Earth. With an apparent size of 18′ x 12′ and a magnitude of 7.4. Discovered in 1792, by William Hershel. It is commonly called the Crescent Nebula, Caldwell 27 looks more sort of a prehistoric dinosaur egg. It is an emission nebula located in the constellation of the Swan, Cygnus. It is a shell of gas that is being energized by the strong stellar wind from the Wolf-Rayet star WR 136, the bright star at the center of the nebula.

(SH2-101) is an emission nebula, that is 6000 light years from Earth. Discovered in 1959 by Stewart Sharpless and has an apparent magnitude of 9.0. Sharpless 101 gets its glow from the hot young star HD 227018 visible within the Tulip. Sh2-101 is a popular astrophotography target not only because of the amount of gas all around, but because it is very close to Cygnus X-1, a micro-quasar and galactic X-ray source that was most likely the first black hole ever discovered from such a source. In photographs, the bow shockwave of extremely hot gas seems to escape from the center of the Tulip.

(WR 134) is a star, a very special star, believed to have started life as an O-type star with at least 25 times the mass of the sun. Their surface temperatures range from 20,000 K to around 210,000 K, which is hotter than almost all other kinds of stars.

Due to their strong emission lines, they can be identified in nearby galaxies. About 500 Wolf–Rayets are cataloged in our own Milky Way Galaxy.

Located around 6,000 light years away from Earth. It’s surrounded by a faint bubble nebula. It’s a popular astrophotography target, but it’s less famous than its cousin the Crescent Nebula.

It was discovered in 1867 by astronomers Charles Wolf and Georges Rayet. Wolf-Rayet stars are very hot, massive stars that are blowing off their outer layers. They are often seen at sites of intense star formation.

Observing Details

Object designation: NGC 6888, SH2-105, Caldwell 27 (Crescent Nebula) | SH2-101 (Tulip Nebula | WR-134 Wolf-Rayet star.

A large H-Alpha emission nebulous area between NGC 6888 (Crescent Nebula) and Sh2-101 (Tulip Nebula) in the constellation Cygnus. The constellation Cygnus is a veritable treasure trove of emission nebulae.

About the Imaging Location

Broemmelsiek Park was made possible by the commitment of Jack and Betty Broemmelsiek to preserve the natural beauty of St Charles County. The original land acquisition of Broemmelsiek Park took place in July 2002, which included a partial donation from the Jack Broemmelsiek family. Located about 6 miles South of Wentzville, Broemmelsiek Park is a St. Charles County Park with a dedicated astronomy site that is open 24/7.

The park is split into three main areas: A main park, an off-leash dog area, and an astronomy view area.

Every Friday night, weather permitting, the Astronomical Society of Easter Missouri (ASEM) members conduct an open house during which most of the telescopes there plus many portable telescopes are used for public viewing. It is a great family event.

The Bortle Scale Class sky for this area is about 5.

Equipment used
The imaging telescope was the RedCat 51, with the ASI2600, mounted to the ZWO AM5 and the ZWO TC40 tripod.

All of my imaging is done in the method of Electronically-Assisted Astronomy (EAA, e.g. based on a live video feed)
I imaged in the narrowband to isolate the hydrogen, oxygen, and sulfur wavelengths; the filter of choice was the Antlia 5nm Dualband Guiding. For electronically assisted astro imaging, I find the ASIAIR smart Wi-Fi device a joy to use, it’s a mini Raspberry Pi computer that you can connect to your phone or tablet via WiFi, giving you control over all of the imaging devices. I did all the post-processing using the software: Adobe Lightroom, Adobe Photoshop, and Pixinsight.

Redcat 51 locked onto its object.


Tablet view of the object.

Acquisition details

RA center: 20h 07m 08s 21 and DEC center: +36° 57′ 34″ 10

I imaged 45 light frames x 300 sec of EXP (3h 45′), with a unity gain of 100, the camera was cooled to -10°F and binned at 1×1. I calibrated the light frames with, 50 darks, 50 dark flats, and 50 flats darks The average moon age was 24.53 days, and the moon phase Waning Crescent phase. On this day, the moon is 23.55 days old and 28.77% illuminated with a tilt of -20.75°. The approximate distance from Earth to the moon is 400,442.85 km and the moon sign is Cancer.

Post Processing Workflow

  • Stack the 45 frames in Pixinsight Weighted Batch Pre Process.
  • Then drizzle the images (Drizzle is a statistical process; it gets better the more frames you use, but requires a reasonable minimum number of frames to work properly.)
  • Make minimal color corrections.
  • Crop it needed.
  • Dynamic Background Extraction, often referred to as DBE, is one of the two primary tools PixInsight offers for identifying and removing these unwanted gradients.
  • Star Size Reduction and Detail Enhancements.
  • Reduce the noise in the Linear data.
  • Switching to Non-Linear: The way to stretch data.
  • Remove any green color-cast pixels from the image
  • Correct any Magenta stars.
  • Curves Transformation and Color Masks to achieve the perfect hue and saturation for each color channel.
  • Enhancing the dark areas in our image such as the interstellar dust lanes.
  • Adding the stars back with PixelMath.
  • Export the final image to Adobe Lightroom or Photoshop.
  • In Adobe fix artifacts in bright stars.

Here is an annotated view of the objects in this region.

Annotated view.

This is the end result of the image capture, 3 hours, 45 minutes of data was stacked, and 1.5 hours of processing in Pixinsight and Lightroom.

Widefield: NGC 6888, SH2-101, and WR 134.

Until the next adventure and thank you for stopping by!

If you enjoyed this article and would like to be notified of future blog posts, please subscribe to my blog – Simply fill in your email address and click “Subscribe”


  1. So fascinating! Too technical for my limited knowledge at this point but it gives me topics to read about and grow. Thank you!

Leave a Reply