Posts by 

Bruce McClure

The mass of a star is determined from binary star systems

Binary stars - a star system consisting of two stars - are extremely useful. They give all the information needed to measure mass of a star. Here is how.

Sirius is a future southern Pole Star

Wait, what? It's true. The sky's brightest star, Sirius aka the Dog Star, will come to within 1.6 degrees of the south celestial pole in the year 66270.

Stellar luminosity versus star brightness

Some extremely large and hot stars blaze away with the stellar luminosity of a million suns! But other stars look bright only because they're near Earth.

Happy Friday the 13th: It’s the 2nd of 2 in 2024

When a year with 366 days starts on a Monday, it's inevitable Friday the 13th will occur twice. In 2024, Friday the 13th comes in September and December.

Meet Pisces the Fish, 1st constellation of the zodiac

Pisces the Fish is a zodiac constellation that is high in the sky on December evenings. Look for it and its asterism, the Circlet of Pisces.

See Orion’s Belt as a celestial bridge between hemispheres

Many know Orion's Belt, a short, straight row of 3 stars. Orion's Belt is considered a celestial bridge between the sky's Northern and Southern Hemispheres.

Meet Libra the Scales, a zodiacal constellation

The zodiacal constellation Libra the Scales is a fixture of the evening sky during Northern Hemisphere summer (Southern Hemisphere winter).

Zubenelgenubi is the alpha star of Libra the Scales

Zubenelgenubi - Alpha Librae - is a double star, and is the second brightest star in the constellation Libra the Scales.

Eta Aquariid meteors are richer from the Southern Hemisphere

The Eta Aquariid meteor shower is better in the Southern Hemisphere because sunrise comes later in May, where it's now autumn and they are moving toward winter.

Cor Caroli, named for the heart of a king

Cor Caroli is a binary star and the brightest star in the northern constellation Canes Venatici, the Hunting Dogs. Its name means Heart of Charles.