The Hunter in the Forest

Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.

Taken in December 2016, this image shows a clear and starry sky over the Masaya Volcano National Park in Nicaragua.

The constellation Orion is the most prominent pattern in this image. Orion is associated with a great hunter according to Greek culture, and is seen here right in the middle. The reddish star in the centre is Betelgeuse, the second-brightest in this constellation and one of the brightest in the night sky. Above and to the right of Betelgeuse we find Bellatrix, another bright star, forming the right shoulder of the hunter. Extending a line from Bellatrix to the right, we find a crookedly aligned group of faint stars comprising Orion’s bow. We can also easily see a group of three aligned bright stars forming the belt of the hunter, an asterism recognised by many different cultures. Just below his belt we can see the silverish glittering that was interpreted as the metal of Orion’s sword or knife by the Greco-Roman tradition. It was alternatively interpreted as a fish roasted on a campfire by some cultures in Australia. In its centre, with binoculars we can see the Small and the Great Orion Nebula, together forming a giant cloud of dust and gas where new stars are being formed. To the lower-left of the silverish compound of tiny stars and nebulae, there is a bright star called Saiph, the Arabic term for “Sword” or “Sabre” because it was considered the tip of a huge knife with a curved upper part. To the right of this, there is the bright bluish star Rigel, an Arabic term which designates it as The Foot of Orion.

Orion’s Belt points up towards Aldebaran at the edge of the photograph and down towards Sirius among the branches of the trees; it is the brightest star in the night sky and is located in the constellation Canis Major. Earth’s atmosphere makes the bright Sirius twinkle in all colours. Seen from space it is pure white, but as its light travels through the air, it is scattered and distorted by the molecules. Therefore, the star appears to change colour like a diamond.

A line connecting the two shoulders of Orion points to another bright star in the lower-left corner of the photograph. This is Procyon, located in the constellation Canis Minor. Procyon has been used by the ancient Babylonians to indicate the heliacal rise of Cancer (whose stars are faint, and invisible in twilight) and to predict the rising of Sirius. Thus, for a very long time in ancient history Procyon was considered a single-star asterism. Perhaps only in Roman times were more stars used to create a constellation in this area of the sky, although this constellation has never been clearly recognisable.

Credit: René Antonio Urroz Álvarez (CC BY 4.0)