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Astrophotography

Deep-sky objects shot from a light-polluted Bortle 8 backyard in Zagreb, Croatia — a Celestron Origin RASA on an alt-az mount, thousands of short subs, narrowband filters and a lot of PixInsight.

Photos are by T & D Astrophotography — Valentina Zadrija and Dinko Korunić, licensed CC BY-NC-ND 3.0. Targets are picked with astro-recommender, which ranks deep-sky objects and comets for tonight’s weather, Moon and telescope.

The Bubble Nebula (NGC 7635)

$ The Bubble Nebula

NGC 7635

About 7,000–8,000 light-years away in Cassiopeia, a massive young star is blowing a bubble into space. The star, BD+60°2522, is an O-type giant dozens of times the mass of our Sun. Its stellar wind races outward at roughly 1,800 km/s and sweeps the surrounding gas into a glowing shell about 7 light-years across.

The bubble isn’t perfectly centered on the star. One side is pushing into a denser molecular cloud, so the shell is lopsided, and the star sits off to one side. The surrounding hydrogen glows red, and oxygen emission gives the bubble its blue-teal edge.

And all of this came from Dubrava, in the middle of Zagreb, under city skies. A triband filter cuts through the light pollution, and thousands of short exposures on an alt-az mount beat the field rotation. Patience did the rest.

5½ hours of photons, one 15-second slice at a time, for one small bubble. Worth every clear night this week.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
1340 × 15 s (~5.5 hours) over one week
Equipment
Celestron Origin Mark II, Antlia Triband RGB Ultra II, alt-az mount
The Pacman Nebula (NGC 281)

$ The Pacman Nebula

NGC 281

Chomping through 10,000 light-years of hydrogen gas in Cassiopeia, this emission nebula owes its iconic shape to an open cluster of young, hot stars (IC 1590) eroding the surrounding cloud with intense UV radiation and stellar winds. The result: a cavity carved into glowing H-II gas that — from our vantage point — looks like it’s ready to eat a few ghosts.

Captured with an Antlia Triband RGB Ultra II filter to pull the Hα and OIII signal out from under the city’s light pollution. 42 GB of raw FITS data, making this the largest project I’ve tackled so far. Stacked and processed in PixInsight with WBPP and drizzle integration.

One of those targets that’s a little easier to appreciate once you know what you’re looking at — the dark intrusion of dust forming the “mouth” is actually a dense molecular cloud resisting the ionization front.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
2685 × 15 s (~11.2 hours) over 5 days
Equipment
Celestron Origin Mark II (RASA f/2.2, 334 mm FL, IMX678), Antlia Triband RGB Ultra II, alt-az mount
The Wizard Nebula (NGC 7380)

$ The Wizard Nebula

NGC 7380

Ionized hydrogen sculpted into a robed figure 8,000 light-years out in Cepheus — an open cluster (Berkeley 5) still carving its own emission nebula out of the surrounding gas. Faint, structurally complex, and criminally underrated compared to its northern-sky neighbors.

Captured from Zagreb under Bortle 8 skies with an Antlia Triband RGB Ultra filter to punch through the light pollution and pull out the Hα/OIII structure. Multi-night integration, stacked and stretched in PixInsight with drizzle to claw back some resolution at native sampling.

Proof that you don’t need a mountaintop to chase narrowband targets — just patience, the right filter, and enough clear nights in a row.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
1200 × 15 s (~5 hours) over 4 days
Equipment
Celestron Origin Mark II, Antlia Triband RGB Ultra II, alt-az mount
The Crescent Nebula (NGC 6888)

$ The Crescent Nebula

NGC 6888

About 5,000 light-years away in the constellation Cygnus lies this beautiful cosmic shell, sculpted by one of the most energetic stars in our galaxy.

At its heart is WR 136, a massive Wolf–Rayet star shedding its outer layers at tremendous speed. Those powerful stellar winds collide with material expelled earlier in the star’s life, creating the intricate filaments and glowing arcs we see today.

Capturing NGC 6888 feels like catching a brief moment in a much larger story — a massive star racing through the final stages of its life, surrounded by the material it has cast into space.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
1200 × 15 s (~5 hours) over 6 days
Equipment
Celestron Origin Mark II, Antlia Triband RGB Ultra II, alt-az mount
The Iris Nebula (NGC 7023)

$ The Iris Nebula

NGC 7023

A cosmic flower blooming through the dust.

The Iris Nebula is a reflection nebula about 1,300 light-years away in Cepheus, illuminated by the young star at its heart. What makes this target special for me are the enormous clouds of dark interstellar dust surrounding the bright blue core — subtle, intricate, and incredibly rewarding to capture.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
1500 × 15 s (~6.5 hours)
Equipment
Celestron Origin Mark II, UV/IR cut, alt-az mount
The Pelican Nebula (IC 5070)

$ The Pelican Nebula

IC 5070

A vast cloud of glowing hydrogen, sculpted by radiation and stellar winds into dark dust lanes and luminous ridges. Located roughly 1,800 light-years away in the constellation Cygnus, the Pelican Nebula is an active stellar nursery where new stars are taking shape deep within the clouds.

There’s something humbling about capturing photons that began their journey almost two millennia ago — and finally ended it on my camera sensor.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
625 × 15 s (2.5+ hours)
Equipment
Celestron Origin Mark II, Antlia Triband RGB Ultra II, alt-az mount
The Western Veil Nebula (NGC 6960)

$ The Western Veil Nebula

NGC 6960

A supernova’s ghost, ~5,000 light-years away. What you’re looking at is the shattered remnant of a star that exploded somewhere between 10,000–20,000 years ago. Those delicate, thread-like filaments are shockwaves still plowing through interstellar gas, lit up as they collide and ionize the material in their path. Also known as the Witch’s Broom for its wispy, swept shape.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
413 × 15 s (~2 hours)
Equipment
Celestron Origin Mark II, Antlia Triband RGB Ultra II, alt-az mount
The Pinwheel Galaxy (Messier 101 · NGC 5457)

$ The Pinwheel Galaxy

Messier 101 · NGC 5457

Twenty-one million light-years away, yet close enough to resolve individual stellar nurseries with a backyard telescope. M101 is a grand-design spiral tilted nearly face-on toward us — every arm, every dust lane, laid bare.

What makes it extraordinary isn’t just the scale (170,000 light-years across, nearly twice the Milky Way), but the density of activity: over 3,000 HII regions catalogued across those arms. You’re not just imaging a galaxy — you’re resolving the birth sites of stars in another island universe entirely.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
947 × 15 s (~4 hours)
Equipment
Celestron Origin Mark II, Optolong L-Pro, alt-az mount
Bode’s Galaxy (Messier 81 · NGC 3031)

$ Bode’s Galaxy

Messier 81 · NGC 3031

12 million light-years of cosmic architecture, one frame. M81 is a grand design spiral with a 70-million solar-mass supermassive black hole at its core. The dust lanes tracing those tightly wound arms aren’t decoration; they’re star formation highways, fed by gas flows from its ongoing gravitational dance with M82.

At mag 6.9 it’s a naked-eye object from a dark site. In a long integration, it rewards you with everything — core, spiral structure, halo, and if your calibration is dialed in, traces of the surrounding IFN cirrus threading through the foreground.

This is one of the northern sky’s finest targets. It doesn’t need neighbors to earn the frame.

Posted
Location
Zagreb, Croatia (Bortle 8 zone)
Integration
391 × 20 s @ ISO 200 (~2.2 hours)
Equipment
Celestron Origin Mark I (6" RASA f/2.2, Sony IMX178), Optolong L-Pro, Celestron alt-az mount
Processing
PixInsight with RC plugins, GraXpert