Farewell to Orion’s colours

The southern hemisphere autumn equinox occurs at 10.01pm on Thursday (March 20). One of the signs of the changing season is the gradual disappearance of Orion after sunset. This glorious constellation has graced our evening skies for months, but as autumn takes hold, it sets earlier each night, soon to be lost in twilight’s glow.

A few weeks back, I made my way to Hoopers Inlet to bid Orion farewell. There, beneath a sky that should have been pristine, I set up my camera to capture the moment when the hunter’s stars slipped behind the dark silhouette of Hereweka (Harbour Cone). Yet, instead of fading as they approached the hills embracing the inlet, Orion’s descent was marred by an untasteful glow — light pollution from Dunedin casting an artificial haze into the night, a stark reminder of the impact of human activity on our celestial views.

Despite this unwelcome intrusion, the inlet’s waters remained undisturbed, reflecting light from the stars above. The brilliant colours of Orion’s stars — ruddy Betelgeuse, icy-blue Rigel, the twin gems of Bellatrix and Saiph, and the sparkling belt of Alnitak, Alnilam, and Mintaka — shimmered upon the water’s surface, their hues revealing the temperatures of these distant suns. Yet, even in reflection, the glow of my adopted hometown provided an unwelcome reminder of how easily human activity erodes our connection with the cosmos.

Throughout my long exposure, the Earth’s rotation revealed itself in elegant arcs of starlight. Orion’s stars traced their final paths toward the western horizon, their reflections stretching into elongated ribbons upon the inlet’s surface. But instead of fading into pure darkness, they were accompanied by the dull orange wash of artificial light — a contrast both disappointing and thought-provoking.

As Orion departed, I turned eastward. Scorpius was rising, its curved form unmistakable. There is an ancient legend that the gods placed Orion and Scorpius on opposite sides of the sky, forever keeping them apart. As Orion vanishes into the west, the celestial scorpion climbs higher each night, its heart — Antares — burning with a deep red glow.

The old hunter may be gone for now, but the cycle of the heavens continues, bringing new wonders with each season.