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SKA-Low
A hundred and thirty thousand two-metre antennas going up on Wajarri Yamaji land, built to see the hydrogen signal from before the first stars.
The sky from here
The sky over this spot is zone 1 — pristine, Bortle 1–2, with a naked-eye limit around magnitude 7.2–8.0. The Milky Way casts a shadow. Airglow is visible, the zodiacal light reaches across the sky, and the darkest places on Earth look like this.
Against that sky 107 of the 110 Messier objects are straightforward in 10×50 binoculars and 107 in a 130mm, with 58 reachable by eye alone. There is nowhere darker worth driving to; this is already among the better skies on the planet.
The Sun drops far enough below the horizon here for full astronomical darkness on every night of the year — which is not true of anywhere much further from the equator.
The centre of the galaxy climbs to 88° at its best — high enough that the summer Milky Way is genuinely three-dimensional rather than a band low in the south. Of the 110 Messier objects, none are circumpolar and 2 never rise.
The sky here is kindest to Lagoon Nebula, Southern Pinwheel and Trifid Nebula, each of which passes within a few degrees of overhead — an object at the zenith is being seen through the least air it will ever be seen through, and the difference against the same object low in the south is not subtle.
Against that, Bode's Galaxy and Cigar Galaxy never clear the horizon here at all. No amount of aperture or patience changes that; the only remedy is to travel.
Read at 26.70°S 116.67°E. Darkness is estimated rather than measured; everything else follows from the latitude and holds along the whole parallel. How accurate this is.
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Questions
What part of the sky never rises at SKA-Low?
Everything north of declination +63°. From 26.7°S that is a cap 27° in radius centred on the north celestial pole, which is 5.3% of the whole celestial sphere. Nothing about the calendar or the aperture changes that — the cap is below the horizon at every hour of every night. Its mirror image, the same 5.3% around the south celestial pole, is circumpolar here and never goes down.
How many hours of true darkness does SKA-Low get?
10 hours 47 minutes on the best night, around 21 June, falling to 7 hours 8 minutes around 21 December. Astronomical darkness is the Sun more than eighteen degrees below the horizon, which is a stricter thing than the Sun being down. Every night of the year gets there eventually, which is the quiet advantage of not being any further from the equator than this.
When is the Milky Way best from SKA-Low?
June and July, and the timing is the whole point. The core transits at midnight around 17 June everywhere, but at 26.7°S that is the depth of winter: the longest nights of the year, sitting underneath the galaxy at its highest. Northern sites get the same transit date during their shortest and least dark nights. It is the single biggest structural advantage a southern observatory has.
How far is SKA-Low from the other sites on this map?
New Norcia ground station is the nearest thing to it here — 485 km to the south. The nearest other observatory is Murriyang — the Parkes dish, 3,110 km to the east. Distances are great-circle, so they are what a signal covers rather than what a road does.