Overview
Horologium, the Pendulum Clock, is a faint southern constellation that most people have never heard of, let alone seen. Hidden in its stars is one of the strangest spirals in the sky. NGC 1512 lies some 38 million light years away, and James Dunlop logged it from Parramatta in 1826 as little more than a smudge. At the center of this frame it reveals itself: a golden bar, a bright core, and wrapped tightly around them a ring of blue so intense it looks lit from within. That ring is a nursery, a few thousand light years across, where gas funneled inward by the bar piles up and ignites into star clusters by the hundred. Hubble made it famous. From Chile, through 24.67 hours of light, it blazes.
Beyond the ring, the galaxy loosens. A pale disk fades outward into faint blue arms that do not close neatly on themselves. One curls around the lower edge and sweeps up the right side of the frame as a long, ragged streamer, far from the bright heart that spawned it. Here the fine detail of the inner ring gives way to the gentle structure of a galaxy being slowly taken apart.
The cause sits at the upper left of the disk: the small blue blob of NGC 1510, a compact dwarf galaxy barely a tenth the size of its neighbor. The two have been circling each other for some 400 million years, and the dwarf’s pull has stretched the big spiral’s arms into these streamers while the spiral, in turn, stirs the dwarf into a frenzy of star birth. The bar and the ring in the center may both owe their existence to this long dance.
The light that built this image left NGC 1512 when whales were only just returning to the sea. Faint galaxies crowd the background, some edge-on, some face-on, each a world of suns at a far greater distance. Among them, a clock-shaped constellation keeps slow time, and two galaxies pull each other apart with great patience.
Captured from my remote setup at Obstech in Chile:
🔭 PlaneWave CDK500 Observatory System
📸 Moravian C3-61000 PRO Camera
🎨 Chroma L, R, G, and B Filters
📀 L: 52×600s, R: 64×300s, G: 72×300s, B: 56×300s (24.67 hours)
🖥️ Processed in PixInsight and Adobe Photoshop