α Piscis Austrini

Alpha Piscis Austrini is Fomalhaut, ‘The Fish's Mouth’, a bright blueish star in the Southern Hemisphere. One of the brightest stars in the heavens, it has a visual magnitude of 1.2 and a distance of 25 light years.

The star is one of the signs that Spring has arrived in the Southern Hemisphere, high in the skies in September and October. To find it in the Southern Hemisphere, locate the Great Square of Pegasus and look nearly overhead, it is the brightest star in the region.

Fomalhaut is relatively young at about 440 million years old, and is expected to live to be at least a billion. There is a planet ‘b’ of undetermined mass, with an orbit of about 1700 years.
     At its original announcement (2008) this object was hailed as the first exoplanet visible in photographic images, thereby proving that the theoretical calculations used to find planets was valid. Yet with more study it has been shown that much of the enthusiasm was misplaced, for massive dust clouds actually prevent any accurate measurements. By 2012 the status became revised considerably; while still said to exist, Fomalhaut ‘b’ might well be only an accumulation of dense dust clouds.

Fomalhaut has a number of fairly bright neighbours: binoculars.

One such neighbour is gamma PsA, a telescopic binary (h5367): 4.5, 8.2; 256º, 4.1".


Drop due south and very slightly to the east, keeping delta on the upper rim of your glasses; you'll find a red dwarf just 10.7 light years away, Lacaille 9352, with a magnitude of 7.5 well seen in binoculars. It has about half the radius of the Sun and half its mass.

Now keeping gamma PsA in view, on your extreme eastern edge, you'll find beta on the western edge.
     Beta PsA is a binocular double (DUN 240): 4.3, 7.1; 172º, 30.6".

Now if you put beta on the opposite side of your glasses then move one field northwest you'll find eta PsA, a fine telescopic binary (BU 276): 5.7, 6.8; 113º, 1.9".

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