The cover of the December 2022 Issue

The First White Dwarf, Black Holes Unmasked, and Planetary Nebulae in Cassiopeia

In the December 2022 issue of Sky & Telescope, we’re on the hunt for the first white dwarf star. While many think Sirius B was the first one to be discovered, that honor actually goes to 40 Eridani. But astronomers knew about Sirius B and 40 Eridani long before they found out about white dwarfs — so the real question is, how did they uncover the true nature of these stars? Plus, astronomers are looking into what stars’ activity means for their exoplanets. Does a more active star produce life or prevent it? And what does that mean for the search for extraterrestrial lifeforms? Then, S&T Science Editor Camille M. Carlisle gives us the low-down on the first image of our galaxy’s central black hole.



The first image of our galaxy’s central black hole gives us a peek at a bizarre object.

By Camille M. Carlisle

Cassiopeia’s Planetary Nebulae

The celestial queen holds a pleasing selection of planetary nebulae. Enjoy them on these winter nights.

By Scott Harrington

The First White Dwarf

The road to discovering a new type of star was long and winding.

By Ken Croswell

A Flare for the Dramatic

What does stars’ tempestuous activity mean for their planets’ habitability?

By Arwen Rimmer

Illuminating Echoes of Light

Here’s how to reveal the reflected light of stellar explosions photographically.  

By Rolf Wahl Olsen

Beyond the Printed Page:

Sketching Planetaries

Check out this awe-inspiring collection of planetary-nebula drawings.

Occultation of Mars

Find out when the Moon will pass in front of Mars in your area.

Mars Profiler

Use our Mars Profiler to plan your observing session.

Black Hole Hunter

Listen to the sounds of the universe and discover gravitational-wave events.


Extra Taurus Treasures

The constellation is more than just a couple of clusters and a bright star.

By Fred Schaaf

A Transitional Mars Opposition

The Red Planet offers a double dose of December observing pleasure.

By Bob King

Layer Upon Layer Upon Layer

Follow the clues leading back to the formation of two large lunar basins.

By Charles A. Wood

Compositional Tips for Astrophotographers

There’s more to a great shot than just getting the exposure right.

By Tony Puerzer

Table of Contents

See what else December’s issue has to offer.


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