At magnitude -26.7, the Sun is too bright to look at without optical aid. Credit: ESO

In astronomy, the brightness of objects is measured by a term called “magnitude”. The lower the number, the brighter the object. The category of first magnitude objects are those that range from magnitude 0.51 to 1.50, with second magnitude 1.51 to 2.50, and so forth. Certain objects are even brighter than first magnitude, peaking in negative numbers at their brightest.

Without optical aid, the human eye can see objects to around 6th magnitude. There are ten natural solar system objects you can see with the unaided eye. (This does not count manmade objects, such as satellites and the International Space Station.)

Here are the top 10 brightest solar system objects, in order from brightest to dimmest: Read the rest of this post …

In this image of Jupiter, the Moon, and Venus taken on February 26, 2012, Jupiter and the Moon are less than five degrees apart and the Moon and Venus (below) are about 12 degrees apart. Credit: Kelly Kizer Whitt

Often when I’m discussing what gorgeous sky events you should be on the lookout for, I describe them in terms of degrees. Perhaps Jupiter is just three degrees away from the Moon, or Saturn and Venus have a close encounter placing them only a half degree apart in the sky. But what, exactly, is a degree?

The sky is split up into 360 degrees. To get a general idea of how to measure degrees, amateur astronomers use their fist held at arm’s length. Extend your arm out from you, make a fist, and the distance from the top of your hand to the bottom is about 10 degrees. This works even though people have different size hands, because a child with a smaller hand will have a shorter arm length and therefore still block out about 10 degrees of sky with this trick. To check it for yourself, extend your arm and fist out toward the horizon. Then place your other arm and fist on top of the first and alternate them until you have counted to nine. You have just measured 90 degrees and your arm should now be straight up over your head, as it is 90 degrees from the horizon to the zenith. Read the rest of this post …

This photo was taken by Michael Rael on March 12, 2013 in Conejos, Colorado, USA.

The elusive comet had started edging into northern skies days earlier, but every sunset brought solid clouds. It wasn’t until March 13 that the day was perfectly clear (and cold), leaving me optimistic for a chance to grab the comet that night.

The Sun was setting as I was having dinner with my kids, and even though I knew I had a bit of time, I got up regularly to look out the window with my binoculars in case it showed early. A layer of distant clouds hung like a curtain across the lowest edge of the horizon, which would be the area where the comet would be once the skies were dark enough to catch it. But I stayed optimistic. Read the rest of this post …

Perhaps it’s because Russia is the biggest country on Earth, or perhaps meteors just look at it from above and find it might be a nice place to visit, but another meteor has exploded over the skies of Russia.

On the morning of February 15, 2013, a meteor estimated at 1 meter across and 10 tons, barreling into Earth’s atmosphere at a speed of at least 54,000 kph, is believed to have exploded above the Ural Mountains of Russia, 29 to 51 kilometers above the ground, according to the Russian Academy of Sciences.

Hundreds of people were injured when they rushed to their windows in the cold winter morning to watch the meteor’s amazing light show. Moments after the meteor’s entry, a shockwave or sonic boom burst windows across the area, spraying observers with glass. Read the rest of this post …

The Beehive Cluster is a dim patch to the left of Venus and the Moon in this photo by John Chumack.

Observing nights are few and far between during winter where I live. Not only is it unbearably cold, it is usually cloudy, too. So on an evening that has temperatures above freezing, it’s worth hauling the telescope out for clear skies or stepping out with binoculars on partly cloudy nights to jump from target to target.

With bright comets predicted to light up our skies this year, it’s an especially good time to locate those binoculars. You can get a peek at the comets in advance and be ready to track them as they enter the range of unaided eyes. March will be the prime month for the first comet of the year, but while you’re waiting for Comet PANSTARRS, there are a number of other good targets outside right now.

Here are some of my favorite binocular objects:

Read the rest of this post …

We recently received this great set of images taken by Prof. Dr Arnold Hanslmeier of the Institute for Physics at Graz University. His astrophotography quite vividly shows the shadows cast on their parent planet by Io and Ganymede, two of the Galilean satellites of the largest planet in our solar system, Jupiter. Dr Hanslmeier captured the images earlier this month using the following equipment: a Meade 15″ telescope and a Celestron Neximage CCD camera.

The Sun and Earth

…to steal a line from R.E.M. And I do feel fine, but that’s because it isn’t really the end of the world as we know it, contrary to what some hoaxers would have you believe. You may have heard that December 21, 2012, will be the end of life on Earth as we know it, and if so, you’ve heard wrong. The end of the world has been predicted countless times before, and as we all know, it has never come true. Sometimes these scenarios involve astronomical events, which makes them all the easier to debunk. Apocalyptic movies such as Melancholia and Seeking a Friend for the End of the World might help fuel some of these fears, but the baseless doomsday warnings floating around the internet are as fictional as the movies. Read the rest of this post …

A view of the Milky Way’s future partner, the Andromeda Galaxy.

The Andromeda Galaxy is one of the best deep-sky targets for autumn and the easiest galaxy to spy. Located in the constellation Andromeda, it is often found using the right half of the W-shape in Cassiopeia to point the way down to it. At magnitude 3.4, it can even be seen without any optical aid, but it’s best to look with a telescope or binoculars first to nail down the location and then try looking with your eyes alone.

M31, as the Andromeda Galaxy is also known, is unmistakable once you have it in the eyepiece. It’s not a bright light that jumps out at you but the large oval of milky gray with its brighter core that makes it stand out from the thousands of stars and background darkness of space. For whatever reason, when I look at Andromeda it always reminds me of the seed of a milkweed, with its solid-looking oval core that is surrounded by a tenuous fuzz. Read the rest of this post …