La Palma

Santa Cruz de La Palma is the island’s capital, strung along the east coast on top of an old lava flow that once ran down from a volcano just south of the city. For a sky trip it plays a particular part: it is the largest gathering of light on the island, the warm glow that spills up into the night from streets and harbour. That glow is precisely what the summit domes were placed so far away and so high to escape. Start your trip here, low and lit, and the darkness you find at the top of the road lands all the harder for the contrast. Even the harbour, bright as it is, cannot fully drown the sky — a reminder that darkness on this island is a matter of degree, and of altitude.

Puntallana is a small town on the northeastern slope, set a few hundred metres above the sea and a short way up the coast from the capital. It sits at a useful middle height — above the brightest coastal lights, well below the summit — and makes a fair place to feel how the sky changes as you climb. Every hundred metres of altitude puts more of the haze-holding air beneath you, and every town you leave behind takes its glow with it. From here the land tilts up toward the dark crest of the island in one direction and drops to the lit coast in the other, so the difference between a washed-out sky and a clean one is laid out in a single view. Nothing here is a destination in itself, but as a rung on the way up it earns a pause.

The climb to the summit is an event in itself, and worth timing for the last of the daylight. The road switchbacks up out of the settled coast and into a broad belt of Canary Island pine — a tall, open forest of long-needled trees that grip the thin volcanic soil and hold it to the slope — before the trees thin out onto bare, dark ground near the top. Somewhere in the middle of the climb you pass through the cloud itself: first a thickening grey, then a moment when the car breaks out the top of it into clear, low light, the cloud spread solid and white below. Drive it slowly toward dusk and you get to watch the sky change from the inside of the weather to a place above it. Stop only at marked pullouts — the drop is real, and the light will be going fast.

The road climbs to a bare, wind-scoured crest of dark rock, and this is where it ends. The white domes strung along the ridge belong to the observatory, set here because it is about as far above the weather and the island’s own glow as the land reaches. Come after dark, well wrapped against the cold, and stand away from any dome light while your eyes adjust — give them a good ten minutes. On a clear, moonless night the sky overhead loses almost nothing to haze or town glow; the thin, dry air is exactly what the telescopes were carried all the way up here to use. Underfoot is nothing but old volcanic rock and the wind; overhead is as much sky as solid ground can offer. This is the point the whole climb has been aiming at, the top of the note as much as the top of the road, and the darkness is worth the drive and the chill to reach it.

Just below the summit ridge the ground falls away into an enormous bowl of eroded rock — the great caldera that dominates the north of the island and gives the national park its name. Steep walls rise on nearly every side, and the observatory stands high on its rim. For a night-sky visitor the bowl’s gift is simple: those high walls cut the low horizon out of your view, and the horizon is where a sky is always dirtiest — the most air to see through, the most distant town glow, the most haze. From a viewpoint on the rim, the rock does that filtering for you, hiding the worst of the low light and leaving the clean sky overhead. Come back by day and the same walls read as a page of the island’s making — flow upon flow of old lava stacked all the way up to the height where you stand.