1941–1960 of 2,097 results
Orion Nebula

Deep Sky

Fuzzies in Your Future:
An Introduction to Deep-Sky Objects

Ready to voyage beyond the Solar System? Here's what you can see.

Night Sky Sights

Finding Uranus and Neptune in 2006

Binoculars and our charts are all you need to spot these twin outer planets.

The crater Tycho seen by Lunar Orbiter 5.

Celestial Objects to Observe

Tycho: The Metropolitan Crater of the Moon

Tycho is the most conspicuous crater visible near full Moon, shining brilliantly and radiating great long rays. But the rays from Tycho that partially encircle the full Moon are not distributed equally in all directions.

Plato proves the point

Celestial Objects to Observe

The Mysteries of Plato

The crater Plato is one of the superstars for observers of the Moon. It's big, conspicuous with its dark floor ringed by a bright rim, and long a subject of speculation, and controversy.

The craters Messier and Messier A

Celestial Objects to Observe

Messier on the Moon

Oblique impact resolves the mystery of one of the most bizarre crater pairs on the Moon: Messier and Messier A. Previous explanations for this crater pair ranged from imaginative to fantastical. All were wrong.

Mare Nectaris

Celestial Objects to Observe

Rings and Things

Mare Nectaris is the smallest of the circular maria on the Moon; lavas extend only 350 kilometers from shore to shore. But the Nectaris basin is beautifully defined by the spectacular Altai Scarp, which forms the southwestern rim of the basin.

Hipparcos satellite

Variable Stars

Mining Hipparcos's Buried Treasure

The satellite caught tantalizing pieces of light curves for many new variable stars. Now it's time to fill in the details.

Celestial Objects to Observe

Solar Filter Safety

Before an eclipse occurs the media often provides information on how to watch the event safely. Unfortunately, despite the best intentions, inaccurate or confusing information on safe observing techniques is often provided. Here are the facts.

Sunspots across the solar face

Celestial Objects to Observe

Sketching Sunspots

Looking for a daytime astronomy project to pursue? Why not set your sights on our nearest star?

Astronomy and Stargazing Projects

Nova Hunters

Few observers have spotted an ever-elusive "new" star. Fewer still have done it twice. Observing styles and techniques are as varied as the searchers themselves.


The Benson Prize

If saving the Earth from destruction isn't enough incentive to find near-Earth asteroids, there's a prize for the amateur who discovers one.

Binary star artwork

Variable Stars

A Treasure-Trove of Variable Stars

Some of the Hipparcos satellite's unfinished business provides fair game for backyard observers.

Celestial Objects to Observe

The Minima of Algol

Now you can calculate the dates and times (local and Universal Times) when the eclipsing variable star Algol should be at its dimmest (magnitude 3.4 instead of its usual 2.1).

The constellation Leo

Variable Stars

The Lure of Variable Stars

Studying and recording the ups and downs of variable stars is a pleasant pastime that can also be scientifically rewarding. Here's a simple project to get you going.

Celestial Objects to Observe

Phenomena of Jupiter's Moons

Virtually any telescope will show Jupiter's four Galilean satellites and their interesting interactions with the planet or its shadow.

Sketch of Jupiter


Jupiter: The Ultimate Observing Guide

Viewing the solar system¹s largest planet can be more than fun — even with a modest telescope, you can make observations of lasting scientific value.

Deep Sky

A Galaxy-Hop in Leo

Even with a modest telescope and a poor sky, you can ferret out many faint, far galactic wonders by using a good map.

Celestial Objects to Observe

A Chain of Galaxies Near M92

Many interesting but faint objects are often overlooked when they're beside a "showpiece" object. A collection of galaxies near M92 are a good example of this.

Deep Sky

A Pair of Grand Galaxies

If you think all galaxies are faint, fuzzy blobs, think again. Here are two easily-seen galaxies that will change your mind.

NGC 2440

Deep Sky

A Collection of Bipolar Planetary Nebulae

Butterflies of the Milky Way await scrutiny with telescopes small and large.