Nebulae on AstroT3k

IC 434 — Horsehead Nebula

Tue, 20 Jan 2026 21:00:00 +0100

IC 434 is a bright curtain of hydrogen‑alpha emission in Orion, ionised mainly by the hot O‑type stars of the Sigma Orionis system. In front of this pinkish glow sits the famous Horsehead Nebula (Barnard 33), a compact pillar of dark dust sculpted by stellar winds and intense ultraviolet radiation. The complex lies about 1,350–1,500 light‑years away on the eastern edge of Orion’s Belt, close to the brilliant star Alnitak (Zeta Orionis).

Visually, this area is challenging. The Horsehead itself is notoriously elusive in small telescopes because of its low contrast; under very dark skies and with a narrowband H‑alpha or UHC filter it can sometimes be hinted at in medium apertures. The wider IC 434 glow and the neighbouring Flame Nebula respond well to filters and long‑exposure imaging.

The field is particularly rich in contrasting nebular types. Immediately east of Alnitak lies the Flame Nebula (NGC 2024), a bright emission and dark‑lane complex. Just south of the Horsehead is the bluish reflection nebula NGC 2023, while faint filaments of IC 434 extend across much of the frame. Bright field stars form striking halos and diffraction around the belt region, adding to the scene.

What else is in this image?

In the image you can also see IC 434 as the background emission sheet, the Horsehead (B33) as a small, notched silhouette, NGC 2023 as a reflection patch below, and the Flame Nebula (NGC 2024) near Alnitak at the left edge. Several catalogued dark lanes thread the field along the Orion B molecular cloud.

View this image on AstroBin: https://app.astrobin.com/u/grodzik?i=iznra1#gallery


Telescope	SkyWatcher 150/750P
Mount	ZWO AM3N
Camera	ZWO ASI2600MC Pro
Filters	Astronomik UHC 2"
Exposure	94 × 120s (3h 8min)
Bortle	5
Moon	Waxing crescent (3.1%)
Processing	Siril, Prism Deep, Axiom2, CosmicClarity

Orion — Wide‑field of the Belt and Sword

Tue, 20 Jan 2026 21:00:00 +0100

The constellation of Orion offers one of the richest wide‑field scenes in the winter sky. This image frames both the Belt (the bright asterism of Alnitak, Alnilam and Mintaka) and the Sword hanging below, with glowing hydrogen clouds and bluish reflection nebulae woven throughout the Orion Molecular Cloud Complex. Amid the Sword sits the famous Orion Nebula (M42), while to the east of the Belt star Alnitak stretches the red emission strip IC 434 with the dark Horsehead silhouette in front of it, and the compact reflection patch IC 435 nearby. The field is permeated by faint dust and H II regions sculpted by massive, young stars.

At the heart of the Sword, the Orion Nebula (M42) is a massive star‑forming region roughly 1,350 light‑years away, where the Trapezium cluster carves a bright cavity in the surrounding gas. North of M42 lies NGC 1977 (the “Running Man” reflection nebula), while much farther north‑east of the frame the giant Barnard’s Loop traces a faint arc of ionised hydrogen encircling Orion. The Belt itself is dominated by hot O‑ and B‑type stars; at its eastern end, Alnitak illuminates the dusty IC 434 Horsehead region together with the bright Flame Nebula (NGC 2024). IC 435, a small reflection nebula adjacent to Sigma Orionis, adds a cool, bluish contrast to the red glow of hydrogen.

The three Belt stars themselves are a study in extremes. Alnitak (ζ Ori) is a hot O‑type supergiant in a multiple system whose fierce ultraviolet radiation excites the Flame Nebula and the IC 434 emission layer; Alnilam (ε Ori) is a luminous blue supergiant whose powerful wind drapes nearby dust with a cool sheen; Mintaka (δ Ori) is a compact multiple of O‑ and B‑type components anchoring the Belt’s western end. Together they ionise and illuminate the intricate mixture of emission, reflection and dark nebulae that thread this field.

From mid‑northern latitudes Orion culminates high in the south between December and February, offering dark‑sky opportunities when weather allows. In binoculars the Belt and Sword are easily recognised, with M42 already distinct as a fuzzy core; small telescopes begin to resolve the Trapezium. Wide‑angle lenses and short telephotos (70–135 mm) excel at capturing the Belt‑and‑Sword composition, revealing the interplay between emission glow and reflection dust. Longer integrations under Bortle 5 skies help bring out the dimmer filaments and dark lanes that stitch the scene together.


Telescope	Canon 70–300 mm lens
Mount	Motorised EQ3‑2
Camera	Canon 600D (astro‑mod)
Exposure	81 × 61s (1h 22min)
Bortle	5
Moon	Waxing crescent (3.1%)
Processing	Siril, Prism Deep, Axiom v2

NGC 2237 — Rosette Nebula

Mon, 19 Jan 2026 21:00:00 +0100

The Rosette Nebula (NGC 2237–2246) is a vast H II emission complex in Monoceros, roughly 5,200 light‑years away. Spanning about 1.3° on the sky—over two full Moons—its cavity and ring‑like envelope outline a star‑forming shell some 130 light‑years across, laced with dark dust lanes and bright hydrogen filaments.

At the heart of the nebula lies the young open cluster NGC 2244. Its hot O‑ and B‑type stars carve the central cavity with powerful stellar winds and intense ultraviolet radiation, sculpting pillars, globules and rippled fronts where new stars continue to form. The rosette‑shaped appearance emerges where the ionised gas meets surrounding molecular clouds.

Observationally, the Rosette is a classic wide‑field winter target for northern latitudes. It is best framed with short‑to‑medium focal lengths and benefits greatly from nebular filters. Visually, under Bortle 5 skies it is subtle, but imaging readily reveals the rich H‑alpha structure—especially with a mild‑band filter that boosts contrast even when some moonlight is present.


Telescope	SkyWatcher 150/750P
Mount	ZWO AM3N
Camera	ZWO ASI2600MC Pro
Filters	Astronomik UHC 2"
Exposure	172 × 60s (2h 52min)
Bortle	5
Moon	Waxing crescent (0.5%)
Processing	Siril, Prism Deep, Veralux, CosmicClarity, Darktable

NGC6888 — Crescent Nebula

Fri, 07 Nov 2025 21:00:00 +0100

NGC 6888, known as the Crescent Nebula, is a wind‑blown bubble in the constellation Cygnus. It forms where the fast, energetic outflow from the Wolf–Rayet star WR 136 rams into slower material ejected earlier in the star’s life, piling up gas into shock fronts and glowing filaments. It lies about 4.7–5 thousand light‑years away and spans roughly 20 × 10 arcminutes (about 25 light‑years across), with bright oxygen‑rich rims and a fainter hydrogen shell.

Discovered by William Herschel in 1792, the nebula sits in the rich Milky Way starfields of the Northern summer sky. For visual observers it is a demanding target that benefits greatly from O III or UHC filters; small telescopes under dark skies can reveal the brightest arc as a delicate crescent.

For imaging, broadband cameras respond well with a UHC filter that suppresses light pollution and enhances emission lines. Longer integrations uncover the subtle web of filaments and the contrasting colours: teal O III arcs wrapping around reddish H‑alpha structures sculpted by intense stellar winds.


Telescope	SkyWatcher 150/750P
Mount	motorised EQ3-2
Camera	Canon 600D (astro-mod)
Filters	Astronomik UHC 2"
Exposure	38 × 120 s + 78 × 120 s = 13,920 s (3 h 52 min)
Bortle	5
Moon	Waning gibbous (94.8%)
Processing	Siril, GraXpert, CosmicClarity, Gimp

M42 — Orion Nebula

Thu, 30 Oct 2025 21:00:00 +0100

M42, the Orion Nebula, is one of the sky’s brightest and most photographed star‑forming regions. Located in the Sword of Orion about 1,350 light‑years away, it is a vast H II region where newborn, massive stars sculpt the surrounding gas and dust. In long exposures the nebula spans well over half a degree, with a luminous core fading into soft, wing‑like outer clouds.

At its heart lies the Trapezium, a compact group of hot O‑ and B‑type stars whose intense ultraviolet radiation ionises the nebula and makes it glow. Turbulent flows, shock fronts and dark lanes thread the scene; subtle colour differences trace different physical conditions — from pinkish hydrogen emission to bluish reflection from fine dust.

Visually, M42 is a rewarding target even from suburban skies. To the unaided eye under darker conditions it appears as a faint patch around the middle star of Orion’s Sword; standard binoculars already show a fan‑shaped glow. Small telescopes reveal the four main Trapezium stars and hints of texture; with increasing aperture and steady air the nebula’s curving wings and internal filaments become increasingly detailed. The best season to observe is the northern winter, when Orion rides high in the evening sky.

The Orion Nebula is embedded in a much larger complex — the Orion Molecular Cloud. Just north lies M43, separated from M42 by a dark dust lane, and above that the reflection nebula NGC 1977 (the “Running Man”). On a grander scale, the luminous arcs of Barnard’s Loop sweep around the region, testifying to past episodes of massive star formation and feedback.


Telescope	SkyWatcher 150/750P
Mount	motorised EQ3-2
Camera	Canon 600D (astro-mod)
Filters	Astronomik UHC 2"
Exposure	91 × 45s (1h 8min)
Bortle	5
Moon	Waxing gibbous (59.3%)
Processing	Siril, Prism Deep, CosmicClarity, Gimp

IC 1848 — Soul Nebula

Fri, 03 Oct 2025 21:00:00 +0200

IC 1848, better known as the Soul Nebula, is a vast H II star‑forming complex in Cassiopeia and the eastern half of the famous Heart and Soul pair. It glows strongly in hydrogen‑alpha, threaded with dark dust lanes and sculpted pillars shaped by the radiation and winds of massive young stars. Embedded open clusters light up the nebulosity; the Index Catalogue designation IC 1848 historically refers to the stellar association within this region.

From mid‑northern latitudes the Soul rises high in the autumn and winter sky, making October evenings a convenient time to image it. Visually it is a challenging, low‑contrast target requiring dark skies; narrowband or broadband UHC filters help bring out the emission. The field here fits well within an APS‑C sensor at 750 mm focal length, framing the brighter central structures along with surrounding filaments.


Telescope	SkyWatcher 150/750P
Mount	motorised EQ3-2
Camera	Canon 600D (astro‑mod)
Filters	Astronomik UHC 2"
Exposure	59 × 120s (1h 58min)
Bortle	5
Moon	Waxing gibbous (84.4%)
Processing	Siril, Prism Deep, CosmicClarity, Gimp

NGC7380 — Wizard Nebula

Wed, 17 Sep 2025 21:00:00 +0100

NGC 7380 is a young open star cluster in the constellation Cepheus, embedded in the large emission nebula catalogued as Sh2‑142. In images they appear together as the Wizard Nebula. It lies roughly 7–8 thousand light‑years away and spans nearly 100 light‑years. The cluster was discovered in 1787 by William Herschel.

The nebula’s colours come from glowing ionised gases: red is mainly hydrogen (H‑alpha), while greens and blues trace oxygen (O III) and sulphur (S II), often combined in the so‑called Hubble palette. The wizard‑like outline is not a solid object; it is sculpted by intense radiation and stellar winds from young, massive stars, shaping clumps of gas and dust where new suns can still form.

For visual observers the target is fairly challenging; it reveals itself best in long exposures and narrowband imaging, which isolates the light of specific elements from the background. Northern‑hemisphere autumn nights favour the hunt for the Wizard, making it a rewarding, detail‑rich subject for practising data processing and colour mapping.


Telescope	SkyWatcher 150/750P
Mount	motorised EQ3-2
Camera	Canon 600D (astro-mod)
Filters	Astronomik UHC 2"
Exposure	27 × 120s (54")
Bortle	5
Moon	Waning Crescent (19.31%)
Processing	Siril, Prism Deep, CosmicClarity, Gimp