Beyond the Stars: Revealing the Double Cluster’s Faint Hα Glow

From a Shared View to a New Imaging Project

The story behind this image began with a shared view through a telescope at our club’s September Public Night. After horrible weather had plagued our public outreach programs, we finally had a clear night and a great turnout of visitors and member volunteers. A few clouds passed through near the scheduled end of the event. By then, most visitors had left, and members were observing or packing up. Outside the observatory, I found the unattended 20-inch Obsession and spent some time observing with it. But I wanted a wider-field view of M11, the Wild Duck Cluster, than that telescope could provide. I asked a member with a really nice 90 mm APO refractor whether he could show us M11. He had started packing up but agreed, and when the sky cleared again, we observed it with another member. Eventually, we turned to the Double Cluster. What a view! A switch to a wider-field eyepiece brought the X-Man asterism in Stock 2 into the same field. Absolutely gorgeous—and even better because I was sharing the experience with fellow members.

If you’re new to astrophotography, subexposures (or “subs”) are the individual exposures combined to make the final image. Broadband data provide the RGB—red, green, and blue—color image. Narrowband data isolate selected emission signals; here, the L-eXtreme filter captured Hα (hydrogen-alpha) and OIII (doubly ionized oxygen). For this image, I added the Hα signal to the RGB data, producing the RGBHα combination.

That eyepiece view set the goal for my next image: capture the Double Cluster and Stock 2 together. The member whose refractor we had used is also an astrophotographer and owns an Askar FRA400. When I bought my own FRA400, he strongly recommended its matching focal reducer. Back home after Public Night, I simulated my rig’s field of view around the Double Cluster. With the reducer, Stock 2 would fit. That sealed the deal—I ordered it. Once it arrived, I installed it and imaged the Double Cluster on the first clear night. During processing, I noticed very faint background nebulosity. I posted the image on our club’s forum and asked whether it was integrated flux nebula (IFN). The same member identified it as Hα emission. After looking at other images on repositories such as AstroBin, I decided to try bringing out more of that faint signal. A run of clear nights in October gave me the opportunity. I first collected about five hours of five-minute subexposures. After processing those data, I spent another night collecting about five more hours, this time with ten-minute subexposures. In the end, I had more than ten hours of narrowband data to add to the almost two and a half hours of broadband data from the original session. For the narrowband exposures, I used an Optolong L-eXtreme dual-narrowband filter, which collects Hα and OIII. In post-processing, I separated the Hα from the OIII and added the Hα to the broadband image. I hope you enjoy the result.

Image 1: The Double Cluster in RGBHα:

Image 1: The Double Cluster in RGBHα. Broadband RGB data capture the colorful star field; added Hα data bring out the faint red background nebulosity.

What is the Double Cluster?

Before getting into the equipment and processing details, it’s worth pausing on what makes The Double Cluster such a compelling subject. The Double Cluster is comprised of two open star clusters that are located very close to one another.

Object type: Open Star Clusters

The Double Cluster, also called Caldwell 14, consists of NGC 869 (h Persei) and NGC 884 (χ Persei). Open clusters contain anywhere from ten to a few thousand stars that formed from the same giant molecular cloud and have approximately the same age. These two clusters are young by astronomical standards—about 14 million years old. NGC 869 has a mass of about 4,700 times the Sun’s mass, while NGC 884 has a mass of about 3,700 times the Sun’s mass. Although their stars are young, the clusters have been known to humans since antiquity; they were first recorded by Hipparchus.

Location in the sky: Perseus, within the Perseus arm of the Milky Way Galaxy

The Double Cluster lies in the constellation Perseus, within the Perseus Arm of the Milky Way. To find it, look between Cassiopeia’s W asterism and Perseus’s Wishbone asterism. Here in Western New York, the clusters are circumpolar: their proximity to the North Celestial Pole means they never set. They are rewarding targets for late-summer and autumn observing or imaging, and appear highest in the sky during late fall and early winter.

Distance / size / scale

Both clusters lie approximately 7,500 light-years from Earth and are separated from one another by a few hundred light-years. In physical size, NGC 869 has a radius of about 35.5 light-years, while NGC 884 has a radius of approximately 50.8 light-years. Their apparent size on the sky is measured in arcminutes: each cluster spans about 18 arcminutes, and the pair together spans about 60 arcminutes. For comparison, the full Moon spans about 30 arcminutes.

Visual features

Unlike many of the objects that we capture with astrophotography, the Double Cluster is a superb visual target. Let’s look at how this target appears visually and in this image.

• Visually with an unaided eye: The Double Cluster appears as a fuzzy patch between the constellations of Cassiopeia and Perseus. As is almost always the case, dark skies and no Moon help.
• Visually with binoculars or a telescope: Binoculars make the Double Cluster easy to find and observe. In a high-quality refractor with a good eyepiece, the stars of both clusters look like diamonds on black velvet, with a couple of red stars adding the sparkle of rubies. A wider field reveals another part of the scene: a conspicuous line of stars leading from the Double Cluster toward the X-Man asterism in Stock 2.
• Astro Imaging: The camera reveals more stars than can be observed visually. As a result, Stock 2 doesn’t stand out to me in this image as it did through the eyepiece. The camera, with enough exposure time, can also detect the faint signal of Hα in the background. Adding narrowband data brought out more of this background as red nebulosity.

The stars’ brilliant pinpoints of color remain the heart of the image. To my eye, the added narrowband data provide a welcome complement: more color in the background and a better balance across the scene.

Why it matters

As the nights grow longer and cooler here in the Northern Hemisphere, it warms the soul to take out a telescope with a high-quality wide-field eyepiece and get lost in the Double Cluster. Whether I’m observing it visually or enjoying it through astrophotography, this object is always a pleasure.

Image 2: RGB versus RGBHα:

Move the slider to compare the broadband image with the version containing added Hα data. Look for the faint red background nebulosity and how it changes the balance of the scene around the stars.

Let me know what you think of this planetarium app in the comments!

Interactive Web Based Planetarium: Stellarium App

Use the live star chart below to locate the Double Cluster tonight. Type 'Double Cluster' into the chart's search bar to find its coordinates.

Tip: Click and drag to scroll the sky, scroll to zoom, or use the search bar to locate specific deep-sky targets.

Prominent Objects in the Field

Object 1: NGC 869 — Open Star Cluster — also known as h Persei, NGC 869 is an open star cluster that makes up the western part of the Double Cluster.

Object 2: NGC 884 — Open star cluster — Also known as χ Persei, NGC 884 forms the eastern part of the Double Cluster.

Object 3: Stock 2 — Open star cluster — Located 2° north of the Double Cluster, Stock 2 is an extended open cluster sometimes called the Muscleman or X-Man Cluster. It is one of 24 open clusters listed in Jürgen Stock’s catalog.

Image 3: Annotated image of the Double Cluster:

Image 3: Annotated view of the Double Cluster field, identifying NGC 869, NGC 884, and Stock 2.

Imaging Details

Capture dates:

• 10/5/2026
• 10/17/2026
• 10/20/2026

·       Location: Eden, NY

·       Target: The Double Cluster

·       Total integration: 12 hours and 54 minutes

·       Exposure breakdown:

• 10/5/2026: 288 subs at 30 seconds each
• 10/17/2026: 62 subs at 300 seconds each
• 10/20/2026: 32 subs at 600 seconds each
• All Exposures: Gain = 100, Offset = 50, and Sensor Temperature = -10 °C

·       Moon and sky conditions:

• 10/5/2026: Moon - 29% illuminated, waning crescent, transparency = good, and seeing = average.
• 10/17/2026: Moon - 43% waxing crescent, transparency = average, and seeing = below average.
• 10/20/2026: Moon — waxing gibbous; reference illumination 72.3% at 9:03 p.m. EDT in nearby Buffalo. Transparency = excellent, and seeing = above average.

Equipment Used

• Telescope: Askar FRA400 w/f/3.9 Reducer
• Camera: ZWO ASI2600MC Pro
• Mount: Sky-Watcher EQ6-R Pro
• Filters: No Filter (10/5/2026) and Optolong L-eXtreme (10/17/2026 and 10/20/2026)
• Guiding: ZWO 30 mm Mini Guide Scope / ZWO ASI290MM
• Control and acquisition software: N.I.N.A & PHD2
• Other accessories: PrimaLuceLab Sesto Senso 3 & SvBony 241 Pro

Processing Details

The processing followed three paths: prepare the RGB image, extract a starless Hα image from the narrowband data, and process the RGB stars separately. I then added Hα to the starless RGB image and screened the processed stars back in. The steps below describe that workflow in detail.

Calibration frames: 50 Darks, 50 Flats, & 50 Dark Flats

·       Calibration and integration: All pre-processing was performed in PixInsight. I created three master light frames: one from the unfiltered data and two from the L-eXtreme data.

Star Alignment: All three master light frames were registered using the Star Alignment process.

·       Crop: I used Dynamic Crop to remove registration artifacts from the registered images. I then applied the exact same crop to the reference image so all images had matching crop boundaries.

Create Hα Image:

• The DBExtract script was used to separate the L-eXtreme data into separate grayscale narrowband images.

• Both resulting Hα images were averaged together with PixelMath to create the Hα image.

• Stars were removed (and discarded) with the StarXTerminator process.

RGB Image Processing:

• Background extraction: Before removing gradients, I plate-solved the image with the Image Solver script and performed Spectrophotometric Flux Calibration. With those prerequisites complete, I used the Multiscale Gradient (MSG) process to remove the gradients.

• Color Calibration: The Spectrophotometic Color Calibration process was used to color balance the image and neutralize the background.

• Deconvolution: Deconvolution and sharpening were applied with BlurXTerminator.

• Stretching: The image was made non-linear with the Multiscale Adaptive Stretch process.

• Star removal: I used StarXTerminator to separate the stretched RGB image into stars-only and starless images. These became the inputs for the separate processing steps below.

Starless Processing:

• Noise reduction: Noise was reduced/removed with the NoiseXTerminator process.

• Adjust Histogram: The histogram was optimized with the Histogram Transformation process.

• Add Hα to RGB:  Hα was added to the RGB image with the CombineHawithRGB script.

• Second Application of Noise Reduction: A second application of the NoiseXTerminator process was used to clean up remaining fine noise in the image.

• Contrast & Saturation: Contrast and saturation were enhanced with the Curves Transformation process.

• Sharpen: The BlurXTerminator process was used to sharpen the image (stellar sharpening and stellar halo reduction were set to zero and a manually entered PSF was used).

• Enhance Contrast: Contrast was further enhanced with the Curves Transformation process.

Star processing: 

• Increased star saturation with the Curves Transformation process.

Combine Starless and Star Images: The PixelMath process was used to screen the stars back into the starless image.

Conclusion

What began as a shared eyepiece view at Public Night became a project to reveal the faint Hα background around a familiar favorite. Capturing and processing that extra signal took time, but the result was worth the effort: the Double Cluster’s brilliant stars set against subtle red nebulosity. I still love this object as a visual target. Imaging it gave me another way to appreciate it—and another reason to spend a clear autumn night under the stars.

A Heart Full of Firsts: Imaging the Heart Nebula

 Our Hearts are Overflowing with Anticipation!

If you ask my wife or me, we will both say the best night of our lives was without question the night our daughter was born. I didn’t think it would be possible to come close to that feeling of pure joy and love. I’m starting to rethink that, as our daughter and son-in-law recently announced they are expecting their first child, our first grandchild. Speaking for my wife and me, our hearts are overflowing with joy and anticipation. As our family prepares nurseries for this new arrival, I would like to dedicate this image of the Heart Nebula—a giant stellar nursery—to my wife, daughter, son-in-law, and expected grandchild.

This image represents another a technical first for me. I used two different dual narrowband filters to capture the data. I used an Optolong L-eXtreme filter to capture hydrogen-alpha (Hα) and doubly ionized oxygen (O III), and an Optolong L-Synergy filter to capture singly ionized sulfur (S II) and O III. This enabled me to process the image in the SHO palette with data from all three emission lines. Since this was my first time processing this combination of data, I found it quite challenging to get a result I was pleased with. After many hours of research, experimentation, and trial and error, I’m pleased with this result. I look forward to the many firsts still to come for our family. Here’s the resulting image:

Image 1: The Heart Nebula (Sh 2-190)

 

Image 1: The Heart Nebula (Sh 2-190) captured from my backyard over two nights in September.

What is the Heart Nebula?

Before getting into the equipment and processing details, it’s worth pausing on what makes The Heart Nebula such a compelling subject. The Heart Nebula is a giant stellar nursery, a vast cloud of gas and dust where new stars are actively forming.

Object type: Emission Nebula with Central Open Star Cluster

The Heart Nebula is a massive emission nebula that is part of a large faint complex of nebulosity known as the W3/W4/W5 Complex. At its center lies the young open cluster Melotte 15. Ultraviolet radiation from its massive stars ionizes the surrounding gas, while powerful stellar winds help sculpt the nebula’s distinctive structure.

Location in the sky: Cassiopeia, within the Perseus arm of the Milky Way Galaxy

The Heart Nebula lies within the Perseus Arm of the Milky Way galaxy in the constellation Cassiopeia. It can be found between the constellations of Cassiopeia and Perseus, next to The Soul Nebula (IC 1848) and not far from The Double Cluster (NGC 884 & NGC 869). This location makes it a great target for late summer and autumn imaging in the Northern Hemisphere. From my location in Western New York, the target is circumpolar; because of its proximity to the North Celestial Pole, it never sets. However, it is best placed, high in the sky in summer and fall.

Distance / size / scale

The Heart Nebula is approximately 7,500 light-years from Earth. It has a radius of about 165 light-years. The Heart Nebula spans about 2 degrees in the night sky, about four times the diameter of the Full Moon.

Visual features

The Heart Nebula exhibits a cavity and shell type structure, which is common for stellar nurseries. The massive stars in the central star cluster power the ionization of the gas and shape the structure with their powerful stellar winds.

• Blue O III nebulosity is strongest within the central region or cavity of the nebula and in the Fish Head Nebula.
• Orange / Yellow Hα and S II emission mark the outer shell of the structure. Faint Hα is also visible in the background of the image.
• Dark Nebulae — concentrated knots of gas and dust that obscure the light behind them — are scattered throughout the image. A superb example is the gill-like structure in the Fish Head Nebula.

The SHO, or Hubble, palette accentuates the contributions of ionized sulfur, hydrogen, and oxygen in a visually striking color scheme.

Why it matters

The Heart Nebula is a stellar nursery that is actively being shaped by the young stars it has already created. The Heart Nebula belongs to the larger W3/W4/W5 complex and forms the brightest part of the W4 Superbubble, also known as the W4 Chimney. This structure may help channel hot gas from the Milky Way’s disk into its halo.

Image 2: Finder Chart for The Heart Nebula (Sh 2-190)

 

Image 2: A finder chart for the Heart Nebula (Sh 2-190).

Prominent Objects in the Field

Object 1: Sharpless 2-190 (Sh 2-190) — Large Emission Nebula — Known as the Heart Nebula, this large emission nebula resembles a heart and is an active region of star formation.

Object 2: IC 1805 / Melotte 15/ Collinder 26 — Open Star Cluster — Located near the lower-right portion of the Heart Nebula in this image, the Fish Head Nebula is one of the complex’s brightest regions and was the first portion to be discovered. The central dense region is referred to as Melotte 15 or Collinder 26. Young by astronomical standards at 1.5 million years old. The stars in this open cluster are the sculptors of the Heart Nebula as their radiation and powerful stellar winds ionize the gas and clear out the vast bubble in the center.

Object 3: NGC 896 / IC 1795 — Bright Emission Nebula –— Located near the lower-right portion of the Heart Nebula in this image, the Fish Head Nebula is one of the complex’s brightest regions and was the first portion to be discovered. The nebula is an active stellar nursery. It contains dense pockets of interstellar gas and thick dust lanes that are being compressed and ionized by massive newborn stars.

Additional details: The field contains numerous Lynds’ Dark Nebulae (LDN) and multiple bright nebulae from Lynds’ Bright Nebulae (LBN).

Image 3: Annotated image The Heart Nebula (Sh 2-190)

 

Image 3: An annotated image of the Heart Nebula (Sh 2-190).

Imaging Details

·       Capture dates:

o   9/7/2026

o   9/26/2026

·       Location: Eden, NY

·       Target: The Heart Nebula (Sh 2-190)

·       Total integration: 7 hours and 21 minutes total

·       Exposure breakdown:

• 9/7/2026: 52 subs at 180 seconds each
• 9/11/2026: 57 subs at 300 seconds each
• All Exposures: Gain = 100, Offset = 50, and Sensor Temperature = -10 °C

·       Filters: Optolong L-eXtreme (9/7/2026) and L-Synergy (9/11/2026)

·       Moon and sky conditions:

• 9/7/2026: Moon - 17% illuminated, waning crescent, transparency = average, and seeing = average.
• 9/11/2026: Moon: New Moon, transparency = above average, and seeing = average.

Equipment Used

• Telescope: Askar FRA400
• Camera: ZWO ASI2600MC Pro
• Mount: Sky-Watcher EQ6-R Pro
• Filters: Optolong L-eXtreme (9/7/2026) & Optolong  L-Synergy (9/11/2026)
• Guiding: ZWO 30 mm Mini Guide Scope / ZWO ASI290MM
• Control and acquisition software: N.I.N.A & PHD2
• Other accessories: PrimaLuceLab Sesto Senso 3 & SvBony 241 Pro

Processing Details

• Calibration frames: 50 Darks, 50 Flats, & 50 Dark Flats
• Calibration and integration: All pre-processing was performed in PixInsight. Two master light frames were created, one for the L-eXtreme data and the other for the L-Synergy data.
• Star Alignment: The L-Synergy master light frame was registered to the L-eXtreme master light frame using the Star Alignment process.
• Crop: Registration artifacts were cropped from the registered L-Synergy image and the exact same crop was applied to the L-eXtreme image using the Dynamic Crop process.
• Create S II, Hα, and OIII images: The DBExtract script was used to separate the L-eXtreme and L-Synergy data into separate grayscale narrowband images.
• Create SHO image: The grayscale S II (red channel), Hα (green channel), & O III (blue channel) were combined into an SHO image using the ChannelCombination process.
• Background Extraction: The GraXpert process was used to remove any gradients.
• Background Neutralization: The background was neutralized with the BackgroundNeutralization Process.
• Color Calibration: The Color Calibration process was used to help color balance the image.
• Deconvolution: Deconvolution and sharpening were applied with BlurXTerminator.
• Stretching: The image was made non-linear with the Multiscale Adaptive Stretch process.
• Star Removal: the stars were removed, producing separate stars-only and starless images, with the StarXTerminator process.
• Starless Processing:
• Noise reduction: Noise was reduced/removed with the NoiseXTerminator process.
• Adjust Histogram: The histogram was optimized with the Histogram Transformation process.
• Second Application of Noise Reduction: A second application of the NoiseXTerminator process was used to clean up remaining fine noise in the image.
• Normalize the SHO Image: The Narrowband Normalization Process was used to normalize the SHO image.
• Contrast & Saturation: Contrast and saturation were enhanced with the Curves Transformation process.
• Sharpen: The BlurXTerminator process was used to sharpen the image (stellar sharpening and stellar halo reduction were set to zero and a manually entered PSF was used).
• Dark Structure Enhance: Regions of dark nebulosity were enhanced with the Dark Structure Enhance script.
• Star processing: 
• Increased star saturation with the Curves Transformation process.
• Removed green noise with the SCNR process.
• Removed Magenta color from stars with the Correct Magenta Stars Script.
• Combine Starless and Star Images: The PixelMath process was used to screen the stars back into the starless image.

Conclusion

Processing this target was more challenging than I anticipated. Combining data captured through two different dual-narrowband filters with a one-shot color camera added complexity to the workflow, but it also made the result especially rewarding. I hope you enjoyed this image of a giant stellar nursery as our family prepares nurseries of its own for the arrival of our first grandchild.

WR 134 (V1769 Cyg)

 Three Nights, One Target ...

This is a personal best for me—not only for total exposure time, but for the patience and persistence it took to capture a target I’ve wanted to image for years. WR 134 is faint, subtle, and notoriously difficult, especially from Western New York, where clear nights are rare and I don’t have the luxury of an observatory. Across three nights, I collected 10 hours and 47 minutes of data—my longest integration to date—and finally gathered enough signal to reveal the delicate OIII bubble surrounding this Wolf–Rayet star.

I processed the image in an HOO palette, mapping hydrogen-alpha (Hα) to red and doubly ionized oxygen (OIII) to green and blue. Because I used a dual-narrowband filter, I captured both emissions at the same time and separated them during processing to build the final composite. Here’s the resulting image:

Image 1: WR 134 (V1769 Cyg)

Image 1: WR 134 (V1769) captured from my backyard over 3 nights in August & early September.

What is it?

Before getting into the equipment and processing details, it’s worth pausing on what makes WR 134 such a compelling subject. The image is not just a pretty field of stars; it captures the visible imprint of a massive star losing material into space and shaping the gas around it.

Object type: Wolf–Rayet star with an ionized wind-blown bubble

WR 134 (also known as V1769 Cyg) is a highly evolved Wolf–Rayet star: a massive, hot stellar core in its final stages of life that is rapidly shedding material. With a surface temperature of about 63,000 K and a luminosity roughly 400,000 times that of the Sun, it drives extreme stellar winds reaching speeds up to 1,700 km/s. Those winds carve out a faint, expanding bubble of ionized gas, visible in narrowband emissions such as hydrogen-alpha and doubly ionized oxygen. The nebula in this image is not a supernova remnant; it is a wind-blown shell, sculpted by continuous mass loss from the star rather than by a single explosive event.

Location in the sky: Cygnus, within the Cygnus OB3 association

WR 134 lies in the rich star fields of Cygnus, only about a degree from the similar Wolf–Rayet star WR 135. Both stars are part of the Cygnus OB3 stellar association, a region filled with massive, short-lived stars. This area sits along the bright band of the Milky Way, making it an excellent target for summer and early autumn imaging. Refer to the finder chart (Image 2) below.

Distance / size / scale

Gaia DR3 measurements place WR 134 at approximately 6,000 light-years from Earth. The surrounding bubble is faint and relatively small compared to supernova remnants, but its structure is revealed beautifully in narrowband imaging—especially in HOO composites where the oxygen-rich arcs stand out sharply against the hydrogen background.

Visual features

The nebula around WR 134 is dominated by:

• Blue-green OIII arcs tracing regions where the fast stellar wind shocks and ionizes surrounding gas.
• Red Hα emission marking slower-moving hydrogen swept up from the interstellar medium.
• Curved, filamentary structures that hint at the star’s rotational wind patterns and possible corotating interaction regions—large-scale structures in the wind that create repeating arcs in long-exposure images.

In HOO processing, these features combine into a distinctive ring-like bubble with layered shells and wisps extending outward.

Why it matters

WR 134 offers a rare look at stellar mass loss in real time. Wolf–Rayet stars shed enormous amounts of material before eventually exploding as supernovae. The bubble around WR 134 shows how these winds shape and enrich the interstellar medium long before the final explosion. WR 134 is also historically significant: it was one of the first stars ever identified as a Wolf–Rayet object due to its unusual emission-line spectrum, helping astronomers define an entire class of massive, short-lived stars.

Image 2: Finder Chart for WR 134 (V1769 Cyg)

Image 2: Finder Chart for WR 134 (V1769).

Prominent Objects in the Field

Object 1: WR 134 (V1769) - Wolf-Rayet Star and associated "Bubble" nebula. The star is located very near the center of the image as indicated in image 3 below. The associated nebula or Oiii ring is concentric to the center of the image.

Object 2: LBN 182 — Large emission nebulosity located from the middle of the frame toward the bottom center. WR 134 and its OIII ring appear embedded within LBN 182.

Object 3: Sh2-104 - A faint emission Nebula located about 14,000 light-years from Earth. It can be found in the upper left of the image. 

Additional details: Open star clusters NGC 6871 and NGC 6883; various dark nebulae, including B146, B147, and multiple Lynds’ Dark Nebulae (LDN); and multiple bright nebulae from Lynds’ Bright Nebulae (LBN).

Image 3: Annotated image of WR 134 (V1769 Cyg)

Annotated image of WR 134 (V1769 Cyg).

Imaging Details

·       Capture dates: August 20, August 28, and September 6, 2026.

• Location: Eden, NY
• Target: WR 134 (V1769 Cyg)
• Total integration: 10 hours and 47 minutes total
• Exposure breakdown:
• 8/20/2026: 74 subs at 180 sec each
• 8/28/2026: 44 subs at 300 sec each
• 9/6/2026: 41 subs at 300 sec each
• All Exposures: Gain = 100, Offset = 50, and Sensor Temp = -10° C
• Filters: Optolong L-eXtreme
• Moon / sky conditions:
• 8/20/2026: Moon 52% First Quarter, transparency = average, and seeing = average.
• 8/28/2026: Moon 100% Full, transparency = above average, and seeing = average.
• 9/6/2026: Moon 26% Waxing Crescent, transparency = above average, and seeing = average.

Equipment Used

• Telescope / lens: Askar FRA400
• Camera: ZWO ASI2600MC Pro
• Mount: Sky-Watcher EQ6-R Pro
• Filters: Optolong L-eXtreme
• Guiding: ZWO 30 mm Mini Guide Scope / ZWO ASI290MM
• Control / acquisition software: N.I.N.A & PHD2
• Other accessories: PrimaLuceLab Sesto Senso 3 & SvBony 241 Pro

Processing Details

• Calibration frames: 50 Darks, 50 Flats, & 50 Dark Flats
• Calibration and integration: All pre-processing was performed in PixInsight 
• Background correction: GraXpert
• Color Calibration: SPCC
• Deconvolution: BlurXTerminator
• Stretching: Multiscale Adaptive Stretch
• Star Removal: StarXTerminator
• Noise reduction: NoiseXTerminator
• Adjust Histogram: Histogram Transformation
• 2nd Application of Noise Reduction: NoiseXTerminator
• Create HOO Image: Narrowband Normalization Process
• Reduce Halos: Combination of Dodge and Burn Process and Blemish Blaster Script
• Sharpen: Image Blend Script (High Pass Filter)
• Enhance Dark Structure: Dark Structure Enhance Script
• Contrast and Saturation: Curves Transformation
• Star processing: 
• Increased star saturation with Curves Transformation
• Removed Green Noise with SCNR
• Removed Magenta color from stars with Correct Magenta Stars Script
• Combine Starless and Star Images: Pixel Math (screen stars)

Conclusion

This target was definitely a challenge. Imaging with a one-shot color (OSC) camera and a dual-narrowband filter with a relatively wide 7 nm bandpass put me at a slight disadvantage. The first two sessions were completed under a bright Moon, which affected the OIII signal more than the Hα signal. Adding the third session, when the Moon did not rise until after the target had dropped below the horizon, helped bring out the faint OIII structure. I may eventually upgrade to a tighter-bandpass filter or even a mono camera with separate emission-line filters, and if I do, I could add that new data to this project. For now, though, I have no immediate plans to change it. This image is done, and I’m pleased with it.

This project reminded me how much faint structure rewards patience. Three nights, three different Moon phases, and a lot of careful processing came together to reveal a bubble I’ve wanted to capture for years.

Barnard's E

 An unplanned imaging session ...

Saturday, August 15, 2026, was supposed to be an outreach night at Penn Dixie Fossil Park & Nature Reserve for Stargazing in Hamburg. The event was cancelled on Friday because of logistical issues and conflicting forecasts. By Saturday afternoon, of course, the forecast had turned clear. Transparency was still poor because of wildfire smoke, and an 11% waxing crescent Moon would set around 9:30 PM, so I quickly searched my target lists for a broadband object to image. I settled on the dark nebulae B142 and B143, which together form Barnard’s E Nebula. I usually spend much more time planning an imaging session with tools like Telescopius, AstroBin, and NINA’s Framing Wizard. This time, the session was improvised. After collecting the data and processing the image, I was disappointed with the framing and thought the image was a lost cause. Then I posted it on our astronomy club’s forum, and several people whose opinions I trust talked me “off the cliff.” I still think the image would be stronger if the “E” were more centered, even if that meant giving up B334, B336, and B337 on the right side. But I also like the contrast between the star colors and the dark nebulae, and the sheer number of stars in the image is breathtaking. I hope you enjoy it too.

Image 1: Barnard’s E Nebula

An image of Barnard's E captured from my backyard on August 15, 2026 with my wide-field deep-sky imaging rig.

Before getting into the technical details, here is a quick overview of what Barnard’s E is and why this region is so striking in a wide-field image.

What is it?

Object type: Dark nebula — Barnard’s E Nebula is the combination of two dark nebulae, B142 and B143. Together, their shape resembles the letter E. Dark nebulae are dense interstellar clouds, often molecular clouds, that block visible light from stars and other background sources.

Location in sky: Barnard’s E is in the constellation Aquila, near the bright star Altair. It is one of many deep-sky gems within the Summer Triangle asterism and is best placed for evening viewing from June through October. See the finder chart in Image 2.

Distance / size / scale: Estimated distance is about 2,000 light-years from Earth. Barnard’s E spans roughly 30 arcminutes in apparent size, about the apparent diameter of the Full Moon.

Visual features: Inky black clouds superimposed on top of a rich field of stars in the heart of the Milky Way.

Why it matters: Dark nebulae are not empty patches in the sky; they are cold, dense clouds of gas and dust. In their central regions, gravity can pull material together tightly enough for new stars to begin forming.

Image 2: Finder chart for Barnard’s E Nebula

Finder Chart for the image of Barnard's E. The red rectangle indicates the field of view of the image.

Prominent Objects in the Field

Object 1: Barnard’s E Nebula is composed of two dark nebulae, B142 and B143. The “E” is located on the left side of the image. E. E. Barnard’s catalogue of dark nebulae was published in 1919.

Object 2: On the right side of the image, three faint dark nebulae are loosely connected. From top right to bottom right, they are B337, B336, and B334.

Additional details: There are several Lynds’ Dark Nebulae (LDN) on both sides of the image. Lynds’ Catalogue of Dark Nebulae was published in 1962 by Beverly Lynds.

 Image 3: Annotated image of Barnard’s E Nebula

An annotated version of the image of Barnard's E.

Imaging Details

·       Capture dates: August 15, 2026.

• Location: Eden, NY
• Target: Barnard’s E Nebula
• Total integration: 4.73 hours total
• Exposure breakdown:
• 8/15/2026: 284 subs at 60 sec each
• Gain = 100, Offset = 50, and Sensor Temp = -10° C
• Filters / channels: N/A
• Moon / sky conditions:
• 8/15/2026: Moon 11% waxing crescent, transparency = poor, and seeing = fair/good.

Equipment Used

• Telescope / lens: Askar FRA400
• Camera: ZWO ASI2600MC Pro
• Mount: Sky-Watcher EQ6-R Pro
• Filters: N/A
• Guiding: ZWO 30 mm Mini Guide Scope / ZWO ASI290MM
• Control / acquisition software: N.I.N.A & PHD2
• Other accessories: PrimaLuceLab Sesto Senso 3 & SvBony 241 Pro

Processing Details

• Calibration frames: 50 Darks, 50 Flats, & 50 Dark Flats
• Calibration and integration: All pre-processing was performed in PixInsight
• Background correction: GraXpert
• Color Calibration: SPCC
• Deconvolution: BlurXTerminator
• Stretching: Multiscale Adaptive Stretch
• Noise reduction: NoiseXTerminator
• Contrast and Saturation: Curves Transformation
• Star processing: Increased star saturation with Curves Transformation. Stars were not removed; a mask was used to protect the background.
• Final cleanup: Applied contrast adjustments with Curves Transformation

Conclusion

Sometimes images don’t turn out the way you expected. Even so, the result can still be pleasing and can spark a sense of beauty and wonder about the cosmos. The contrast between the colorful stars and the inky black wisps of dark nebulosity makes this image successful in my eyes. I am still struck by the sheer number of stars in the frame: all of those suns, each likely surrounded by at least one planet, and possibly more.

Reprocessing Old Data - Reflection in the Dark - The Iris Nebula

 A long-Overdue Update and a Fresh look at the Iris Nebula

It has been a while since my last post. The past few months have not left much time for imaging or writing, but I have still been active in the hobby - attending NEAF (Northeast Astronomy Forum), participating in astronomy outreach, and working with our club's imaging group to install and tune some new gear.

Since I don't have any data to play with, I decided to try and reprocess some old data with new tools and techniques. I chose my image of the Iris Nebula (Reflection in the Dark). The Iris Nebula is a great test subject for reprocessing because it combines bright reflection nebulosity with dim dark dust. This makes it a challenge to bring out the dark nebulosity and dust without blowing out the brighter regions. You can view the original blog post here.

The two new tools that I used in processing this image were Multiscale Gradient Correction (MSG) and Multiscale Adaptive Stretch (MAS) in PixInsight. MSG is newer tool in PixInsight that removes the gradient in the background of the image. This tool worked well for this image but is not my first choice for gradient removal as it is tedious to use. MAS is new tool for making an image non-linear (stretching). I really like this tool, it allows a lot of control and retains good color saturation. I believe the resulting image has a much cleaner background and the dark dust/nebulosity has improved contrast. 

Reprocessed Version of the image:

Reflection in the Dark - The Iris Nebula - Reprocessed in June 2026. Image originally captured in May 2023.

Before and After Slider:

Processing Details:

Linear Processing:

• Started with existing master from original processing run
• Spectrophotometric Flux Calibration (prerequisite for Multiscale Gradient Correction)
• Multiscale Gradient Correction to remove the gradient
• BlurXTerminator (Correct Only) to fix any star aberrations
• Spectrophotometric Color Calibration to color calibrate and neutralize the background
• BlurXTerminator (Full) to perform deconvolution and sharpening

Non-linear Processing:

• Multiscale Adaptive Stretch to make the image non-linear
• StarXTerminator to remove the stars

Non-linear Process - Starless Image:

• NoiseXTerminator to remove noise
• Histogram Transformation to make adjust the histogram after noise reduction
• Create HDR Script to recover detail in bright areas of the image
• NoiseXTerminator - additional noise reduction
• Curves Transformation to add Saturation
• Curves Transformation to add intensity and contrast
• Image Blend Script for sharpening
• Exponential Transformation for additional intensity and contrast

Conclusion:

It was fun to come back to older data and rework it with newer tools and techniques. This project was a good reminder that old data can still have something new to offer, especially as processing tools improve and our own skills continue to develop. Hopefully the stars align soon and I am able to collect some new data. In the meantime, stay curious and keep looking up!

Clear Skies!

Ernie

Wide‑Field Astrophotography of Orion: Horsehead, Flame, and Orion Nebula in RGB + Hα

 Two clear Sundays in a row ...

Orion is one of the most popular constellations for astrophotography. With showpiece objects like the Orion Nebula and the Horsehead Nebula, you can’t go wrong pointing your telescope there on the few clear winter nights we get. Sunday, March 1st was forecast to be clear, so I slewed my telescope to the central spine of the Orion Molecular Cloud Complex — framing the Horsehead/Flame region and the Orion Nebula (M42/M43), with the Belt stars Alnitak and Alnilam anchoring the field.

The Moon was nearly full that night, so I used my Optolong L‑eXtreme filter to tame the bright sky. The following Sunday, March 8th, was also clear, but this time the Moon didn’t rise until after midnight. That gave me a chance to capture the field in broadband RGB with no filter. The final image is a composite of the RGB data from March 8th and the Hα extracted from the dual‑narrowband data from March 1st.

Image 1: RGB + Ha image of the central spine of the Orion molecular Cloud Complex

RGB + Ha image of the central spine of the Orion Molecular Cloud Complex captured from my backyard on 3/1/2026 & 3/8/2026.

What is it?

This field captures the central spine of the Orion Molecular Cloud Complex, one of the richest and most active star‑forming regions in the night sky. The combination of bright emission nebulae, dark dust clouds, reflection nebulae, and massive blue stars makes this area a favorite for both astrophotographers and professional astronomers.

Image 2: Annotated image

An annotated version of the image.

Prominent Objects in the Field

Horsehead Nebula (B33) - The Horsehead Nebula, also known as Barnard 33, is a dark nebula silhouetted against the red glow of the emission nebula IC 434. Its dense dust cloud blocks the background light, creating the distinctive horse‑head shape that makes it one of the most recognizable objects in the night sky.

Flame Nebula (NGC 2024) - The Flame Nebula is an emission nebula next to the leftmost star in Orion’s Belt, Alnitak. Dark dust lanes cut through the bright emission region, and smaller branches of dust radiate outward, enhancing its resemblance to a flickering flame.

Orion Nebula (M42) & De Mairan's Nebula (M43) - M42 is arguably the most popular target for amateur astronomers (both visual and astrophotography).  This area is a bright H II region and an active stellar nursery. M42 is a massive star forming region and is (astronomically speaking) relatively close to the Earth. M43 is just north of M42. M42 and M43 are separated by a dark dust lane.

Running Man Nebula (Sh 2‑279) – The Running Man is a combination of emission and reflection nebulae located just north of M42 and M43. Bright blue starlight reflects off surrounding dust while faint H II emission fills the background, creating the distinctive “running” silhouette that gives the nebula its name. 

Alnitak and Alnilam - Alnitak is the leftmost star and Alnilam is the middle star in Orion's belt. Both stars are bright Type O/B stars. 

How big is it?

For reference, the Moon has an apparent size of 31 arcminutes.

Horsehead Nebula (B33) - The Horsehead Nebula has an apparent size of 6 x 4 arcminutes on the sky with an actual diameter of 2.8 light-years (ly). 

Flame Nebula (NGC 2024) - The Flame Nebula has an apparent size of 30 x 30 arcminutes on the sky with an actual diameter of 7.1 ly.

Orion Nebula (M42) & De Mairan's Nebula (M43) - M42 has an apparent size of 85 x 65 arcminutes on the sky with an actual diameter of 34.7 ly. M43 has an apparent size of 20 x 15 arcminutes on the sky with an actual diameter of 10.2 ly.

Running Man Nebula (Sh 2-279) - The Running Man Nebula has an apparent size of 40 x 25 arcminutes on the sky with an actual diameter of about 15 ly.

How far is it?

Distance estimates for the Nebulae in this image range from 1,260 to 1,600 ly from Earth.

Alnitak is about 740 ly and Alnilam is about 2,000 ly from Earth.

How to find it?

Refer to the red rectangle in the finder chart below. 

Let's start with the easiest objects to find, Alnitak and Alnilam. Alnitak is the leftmost star and Alnilam is the middle star in Orion's Belt. Both Stars are visible with just your eyes, and can be seen from just about anywhere.

Just below Orion's belt are three stars (maybe 2 depending on light pollution and sky conditions) known as His Sword. M42 is the middle "star" in the sword. Visible to the naked eye (light pollution and sky conditions depending) as a fuzzy star. Easily observed in binoculars and telescopes. 

The Horsehead is "easy" to find but very difficult to actually see (visually). Think of trying to see a black smudge on a black tablecloth. Although it is difficult to visually observe, it is relatively easy to image. To visually observe the Horsehead Nebula, a 10" or larger telescope, H-beta filter, and dark skies are required. The Horsehead is located about 1 degree south of the bright star Alnitak (the leftmost star in Orion's belt). 

Image 3: Finder Chart

Finder chart for the field.

Processing:

My goal with this image was to preserve natural star colors from the RGB data while using Hα to enhance the emission structures in IC 434, the Flame Nebula, and the extended nebulosity around M42. The workflow below reflects that balance.

Narrowband Workflow:

Linear Processing: 

• Gradient removed with MSG. 

• The narrowband image was aligned to the RGB image with Star Alignment. 

• The registered image was cropped using Dynamic Crop and the instance of the process was saved to the desktop so it could be used to duplicate the crop on the RGB image. 

• BlurXTerminator was used for deconvolution

• The stars were removed with StarXTerminator. (The narrowband stars were not saved)

• Noise was reduced with NoiseXTerminator. 

• The image was made non-linear with Generalized Hyperbolic Stretch. 

Non-linear processing: 

• The image was separated into the R, G, & B channels using Channel Extraction. 

• The R image was used as the Ha image and the B & G (Oiii) images were discarded.

RGB Workflow:

Linear Processing: 

• Gradient was removed with MSG. 

• The image was cropped to duplicate the narrowband images with the saved instance of Dynamic Crop.

• BlurXTerminator was performed in correct only mode. 

• Color calibration was performed with SPCC.

• BlurXterminator was used for deconvolution.

• The stars were removed (and saved) with StarXTerminator.

Starless linear processing:

• The image was made non-linear with Generalized Hyperbolic Stretch.

Starless non-linear processing: 

• The toolbox CombineHawithRGB script was used to blend the Ha into the RGB image.

• I used the CreateHDRImage script to tone down the core of the Orion Nebula.

• Image blend was used for sharpening by using the high pass filter. 

• CT was used to enhance color and color saturation.

Star Processing:

• Stars were stretched with Seti Astro's Star Stretch script.

• CT was used to enhance color and saturation.

Final Blend

• The stars were screened back into the starless image with PixelMath. 

Image Details:

Narrowband Image:

Capture Date: 03/01/2025

Location: Eden, NY

Telescope: Askar FMA180 Pro

Camera: ZWO ASI2600MC Pro

Filter: Optolong L-eXtreme

Mount: Sky-Watcher USA EQ6-R Pro

Exposure: 45 exposures @ 180 sec each for a total exposure of 2 hours and 15 minutes. All exposures were captured at Gain 100 / Offset 50 / -20°C each.

Software: NINA, SharpCap Pro, PHD2, and PixInsight

RGB Image:

Capture Date: 03/08/2025

Location: Eden, NY

Telescope: Askar FMA180 Pro

Camera: ZWO ASI2600MC Pro

Filter: N/A

Mount: Sky-Watcher USA EQ6-R Pro

Exposure: 108 exposures @ 60 sec each for a total exposure of 1 hour and 48 minutes. All exposures were captured at Gain 100 / Offset 50 / -10°C each.

Software: NINA, SharpCap Pro, PHD2, and PixInsight

Total Integration Time: 4 hours and 3 minutes

Clear Skies!

Ernie