Posts by 

Don Machholz

Deneb: How astronomers know how far away it is

The star Deneb - part of the Summer Triangle - is one of the most distant stars you can see with your eye alone. Why don't we know its distance precisely?

Polaris is the North Star

Many people think Polaris is the brightest star, but it's only 50th in brightness. Still, Polaris is famous because the entire northern sky wheels around it.

Comet Halley, parent of 2 meteor showers

The famous comet Halley spawns both the May Eta Aquariid meteor shower and the October Orionid meteor shower.

Arcturus, brightest star of the north

Arcturus is the brightest star north of the celestial equator. Near the handle of the Big Dipper, it's easy to find in spring in the Northern Hemisphere.

Baily’s beads seen during a solar eclipse

May 15, 1836: Francis Baily, an English astronomer, saw light shining through lunar ridges during an eclipse of the sun. These are now known as Baily's beads.

Meet Regulus, the Lion’s Heart

The bright star Regulus in Leo the Lion is prominent in the evening sky in May. It looks like a single point of light, but is really 4 stars.

Darn! Comet C/2021 O3 PanSTARRS has disintegrated

Astronomers hoped comet C/2021 O3 (PanSTARRS) would get bright after its April 2022 sweep near the sun. Instead, it disintegrated.

The Bortle survival limit for comets

Astronomers learn even from failed comets. The Bortle survival limit gives us a prediction as to whether a comet will survive perihelion.

Meet M13, the Great Cluster in Hercules

Many stargazers call it the finest globular cluster in the northern half of the heavens. It's M13, also known as the Great Cluster in Hercules.

Asteroid Apophis to sweep close 7 years from now

Apophis' flyby in March 2021 enabled astronomers to conclude there's no chance this asteroid will strike Earth anytime soon. The next flyby will be in 2029.