Octans
Octant
Stagnation
An octant is an instrument used to measure the altitude of a star accurately, and is said to have made accurate measurements possible even on a rocking ship at sea. There were also instruments called the quadrant and sextant, and all three once had constellations named after them. Today, however, only Sextans and Octans remain as constellation names.
The most important feature of Octans is that the south celestial pole lies within its boundaries. In Sisask’s handwritten score, the position of the south celestial pole is also marked beside Octans.
The image above shows star trails captured by a rooftop camera at the Martin A. Pomerantz Observatory (MAPO) in Antarctica, with a green aurora also visible.
I previously wrote that Vega in Lyra will become the new North Star in about 12,000 years, replacing our present North Star, Polaris in Ursa Minor. But what do you think will happen at the south celestial pole then? Will there still be no South Pole Star, as is the case today? No! Surprisingly, Canopus in Carina is expected to become the South Pole Star.
Sisask’s image for Octans is “Stagnation.”
Sisask also wrote of Octans, “It is a mysterious constellation marking the south celestial pole.” It is worth remembering that, as seen from the South Pole, Octans never sets below the horizon but remains near the zenith.
In the music of Octans, rapid triplet figures are used as if carrying on from Chamaeleon, and the passages trace broad arcs. A distinctive feature is that the opening two measures are repeated many times, each time coming to a halt on a fermata. Sisask instructs the performer to “hold all fermatas for as long as possible.” There is no time signature, and the tempo alternates repeatedly between Allegro and Largo.
What might the stars circling around Octans look like? An aurora or a meteor may suddenly streak across the sky. At each moment of stillness—the fermatas—the scene before our eyes may change, and our imagination may deepen.
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