2061–2080 of 2,187 results

Celestial Objects to Observe

Open Clusters by the Season

Open clusters are popular targets for deep-sky observers, particularly when composed of varied-color stars. Here are some treats for scopes both large and small.

Celestial Objects to Observe

A Sampling of Star Clusters

You don't need a big telescope to be dazzled by deep-sky wonders, particularly if your target is one of the many lovely star clusters.

The Straight Wall at last quarter

Celestial Objects to Observe

Ancient Thebit and Huygens's Sword

The absolute best example of a lunar fault is the Straight Wall. This well-known lunar feature is a long thin line that never fails to impress; even through a small telescope it's a fascinating sight.

Rising full Moon


What Is A Blue Moon in Astronomy?

Is Friday's full Moon "blue"? Depends on who you ask, but if someone answers yes, it's because of a mistake in a 1946 issue of Sky & Telescope.

Albireo photo

Double Stars

Leading a Double (Star) Life

Double stars show us color combinations we seldom see anywhere else in the sky. Viewing these stellar twins yourself is fun and easy.

Delta Cephei

Celestial Objects to Observe

Seeing Double (Stars)

Spotting double stars is always a stargazing treat! Here are some targets to get you started.


Celestial Objects to Observe

Orion's Splendid Double Stars

Some of the finest double and multiple stars in the sky are on display as the constellation Orion, the Hunter, comes to prominence.

Trapezium stars in the Orion nebula

Celestial Objects to Observe

Pretty Double Stars for Everyone

Double stars can be found everywhere. Here's a selection of pretty doubles vislble when Orion the hunter is riding high in the sky.

Double star Gamma Leonis

Celestial Objects to Observe

More Pretty Double Stars

When the Milky Way is prominent, don't overlook the wealth of pretty double stars visible during this season.

Camcorder for occultations


Camcorder Timing Tips

Many households now possess a camcorder. Many amateur astronomers may be unaware that these devices are sensitive enough to record occultation events.

Celestial Objects to Observe

Occultations: The Fastest Things in the Sky

Watch in your telescope as the edge of the Moon snaps a star out of sight.

Southern Cross

Double Stars

Southern Double-Star Gems

The treasure-filled skies of the Southern Hemisphere offer observers more than showpiece clusters and nebulae.

Ron Tanguay

Double Stars

Observing Double Stars for Fun and Science

Amateur observations of visual double stars are desperately needed. Here¹s how you can take the plunge.

solar prominence

Hobby-based Q&A

Why do you need a hydrogen-alpha filter to see solar prominences?

If I can see solar prominences with the naked eye during a total eclipse, why do I need a hydrogen-alpha filter to see them at other times? During a total eclipse the Moon completely blocks the Sun’s photosphere, or visible “surface,” allowing prominences (and the corona) to shine in all…

International Space Station

Space Satellites

Take a "Sat-seeing" Tour

It’s a bird! It’s a plane! It’s the International Space Station! Learn how to spot Earth's artificial satellites.

Green Ripples

Celestial Objects to Observe

Catch the Green Flash!

It sounds like a comic-book superhero, but this brief spectacle marks the end of daylight with a burst of color.

Variable Stars

R and T Coronae Borealis: Two Stellar Opposites

One is usually bright but fades unexpectedly; one is almost always faint but brightens unexpectedly. Check them out with binoculars.

Celestial Objects to Observe

A Solar Observing Refresher Course

With modest equipment and attention to safety, you can enjoy observational astronomy throughout the day.

Sun through hydrogen-alpha filter


Observing the Sun Safely: Sunspots, Faculae, and Flares

The surface of the Sun is a dynamic, living place that can change unpredictably from day to day.


How and Why to Make Occultation Timings

Lunar and planetary occultations may be appreciated for their intrinsic beauty, but in order to contribute scientifically valid data you need to apply certain techniques.