Messier 7 - The Ptolemy Cluster

Named after it’s discoverer Ptolemy, M7 has a long history of observation. First recorded in the 1st-century, M7 was then later observed in 1654 by Giovanni Batista Hodierna with the advent of the telescope, and it then cataloged by Charles Messier in 1764. M7 is a loose collection of stars known as an open cluster, situated near the stinger of the Scorpion in the constellation Scorpius. By being such a cluster, we may note that all of the stars within the cluster are of similar age and chemical composition, as they hail from the same molecular cloud. It is easily spotted with the naked eye!

Top: Wide-Field - Anthony Urbano

Bottom: Close-Up - ESO

Messier 6 - Butterfly Cluster in Scorpius

Our first open cluster in the Messier Catalogue, M6 displays a loose collection of  bright stars. Open clusters are relatively young objects in the night sky. Their stars originated from the same molecular cloud, and while varying in size and colour, they share the same chemical composition. M6 is visibly blue, due to the large population of bright B type stars. It was discovered in 1654 by Giovanni Battista Hodierna or possibly early by Ptolemy in the 1st century AD. It was recorded by Charles Messier in 1764.

Top: Wide-Field - Anthony Urbano

Bottom:Close-Up - Ole Nielsen

Messier 5 - Globular Cluster in Serpens

Discovered by Gottfried Kirch in 1702 and later cataloged by Charles Messier in 1764, M5 is one of the largest globular clusters known. It is so large that given the right conditions, it can be seen as a faint star with the unaided eye. M5 is also one of the oldest globular clusters and contains more than 100,000 stars. It is also known for several variable stars and even a dwarf nova!

Top: Wide-Field - NASA

Bottom: Close-Up - ESA/NASA/Hubble

Messier 4 - Globular Cluster in Scorpius

M4 is yet another globular cluster, located just west of the star Anatares. Catalouged by Charles Messier in 1764, M4 is an easy target for any telescope. As such, it was the first globular cluster in which individual stars were resolved. The stars of globular clusters are some of the oldest in the galaxy, and especially for M4 as some of the white dwarfs are about 13 billion years old - nearly the age of the universe itself!

Top: Wide-Field - Rainer Sparenberg

Bottom: Close-Up - NASA/Hubble



CYGNUS: Swan of the Night Sky

Dominating the summer sky, Cygnus is one of the largest constellations and one of the most recognisable. Comprised of about nine stars, the pattern of Cygnus follows as a swan in flight. Go outside a few hours after dark and look towards the east. You should be able to make out a cross lying on its side. You’ve done the hard work already! The horizontal bar of the cross represents the body of the swan and the vertical arms of the cross represent its wings. The bright star Deneb is the swan’s tail and Alberio is its head. If it’s really dark, you might even notice a faint band of light stretching across the sky – it’s our galaxy the Milky Way!  The Swan flies along the Milky Way!

Now the cross itself is quite an easy pattern to see and is what we astronomers call the “asterism” known as “The Northern Cross”. Simply, an asterism is a pattern in the night sky which is easy to see. A constellation on the other hand is one of the 88 official patterns selected by the International Astronomical Union (IAU). And for modern astronomical purposes, a constellation also includes the area around the constellation, as marked in the chart. For example, although Tau Cygni is not a part of the swan itself, it is still considered a part of the constellation. And while The Northern Cross exists as part of the swan, it excludes the wing tips and is therefore an asterism. In addition, the Northern Cross was an important symbol to early Christians because during particular months it appears upright in the sky, hence the cross. And now it might be surprising, but the most famous of these asterisms is actually the Big Dipper, which makes up the tail and back of Ursa Major, the Big Bear! There are plenty of easily-found asterisms in the night sky – try to track them down!

Cygnus has some truly remarkable stars. The bright star Deneb, which again is the tail of the swan, is also a part of a massive asterism called “The Summer Triangle” which comprises three bright stars: Deneb, Vega, and Altair. Each of these stars belongs to their own constellation. Vega is part of Lyra the Harp (or Lyre) and Altair is part of Aquila the Eagle. The somewhat dim star Alberio makes up the head of the Swan, and is actually two stars! It’s what astronomers call a “binary system”, meaning that there are two stars orbiting each other. If our own solar system was one of these binary systems, we would see not one sun, but two suns in our daytime sky! Now these two stars, unimaginatively named Alberio A and Alberio B, are strikingly different in appearance. While one star is bright gold, its smaller companion shines with a sapphire blue hue. It’s my all-time favourite! I like to say that these two stars are the jewelled eyes of the swan. One for the bucket list!

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Messier 3 - Globular Cluster in Canes Venatici

This globular cluster is arguably one of the most studied of all of it’s kind due to a large number of variable stars. In general, most globular clusters are very old objects in the night sky, made up of several thousand stars. It is thought that they are remnants of a previous stage of our own galaxy, as they are found frequently above and below the galactic disk. Charles Messier discovered the cluster in 1764 and although it’s difficult to find without a telescope, it is one of the best sights of the northern sky.

Top: Wide-Field - Eastex Astronomy

Bottom: Close-Up - Robert J. Vanderbei.

Messier 2 - Globular Cluster in Aquarius

A globular cluster such as M2 is one of the oldest types of objects in the the galaxy, thought a remnant of an earlier stage in the evolution of our galaxy. They are usually located outside of the galactic disk and are comprised mostly by old dying stars, hence we can know it’s age. M2 specifically is 37,500 light-years distant and in exceptionally dark skies can be seen without assistance, located in the constellation Aquarius. Discovered first by Jean-Dominique Maraldi in 1746, it was re-discovered and cataloged by Charles Messier in 1760.

Top: Wide-Field - Tom Diana/

Bottom: Close-Up - NASA/HST

The scientist has a lot of experience with ignorance and doubt and uncertainty, and this experience is of very great importance, I think. When a scientist doesn’t know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty darn sure of what the result is going to be, he is still in some doubt. We have found it of paramount importance that in order to progress we must recognize our ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degrees of certainty — some most unsure, some nearly sure, but none absolutely certain.
Richard P. Feynman - The Value of Science (1955)
Science is much more than a body of knowledge. It is a way of thinking. This is central to its success. Science invites us to let the facts in, even when they don’t conform to our preconceptions. It counsels us to carry alternative hypotheses in our heads and see which ones best match the facts. It urges on us a fine balance between no-holds-barred openness to new ideas, however heretical, and the most rigorous skeptical scrutiny of everything — new ideas and established wisdom. We need wide appreciation of this kind of thinking. It works. It’s an essential tool for a democracy in an age of change. Our task is not just to train more scientists but also to deepen public understanding of science.
Carl Sagan in “Why We Need To Understand Science” in The Skeptical Inquirer Vol. 14, Issue 3 (Spring 1990)

Messier 1 - The Crab Nebula

The Crab Nebula (Messier 1) is a supernova remnant in constellation of Taurus. A supernova remnant is the stage in stellar evolution following a supernova, which is one of the most violent events in the universe. Once the star can no longer sustain itself through fusion, it explodes. The outer layers are blown off and what’s left is usually a neutron-star/pulsar. M1 has an apparent magnitude of 9.0 and is about 6,300 light years away. Japanese and Chinese (and probably Native American) astronomers recorded the original supernova nearly 1,000 years ago in 1054!

Top: Composite - NASA, ESA, J. Hester and A. Loll (Arizona State University)

Middle1: Wide Wavelength Composite - X-Ray: NASA/CXC/J.Hester (ASU); Optical: NASA/ESA/J.Hester & A.Loll (ASU); Infrared: NASA/JPL-Caltech/R.Gehrz (Univ. Minn.)

Middle2: Filaments of the Crab - NASA and The Hubble Heritage Team (STScI/AURA)

Bottom: Optical/XRay Pulsar - NASA/HST/ASU/J. Hester et al.

Off to bed because I want to be up for the NASA Cygnus Cargo ISS docking tomorrow morning at 5:15 EDT!

Come join hundreds of spectators at NASA TV:

And in case you missed the launch:

Seeing Double: Summer’s Binary Stars

Years ago, my younger daughter Maria and I camped in northern Minnesota. One chilly evening in August during the Perseid meteor shower, we built a big fire and stretched out on our backs next to it to stay warm.

Vega beamed down from overhead, and next to it, the famous double-double star, Epsilon Lyrae. I asked my daughter and her young eyes to see if she could split the wider pair, Epsilon1 and Epsilon2. She looked for a minute and then said: “Sure, Dad, one is right above the other” — then she added, “Can’t you?”

Read more…
Ever looked at the sky and thought “wait, isn’t there two stars?” Well you might just be right! The summer sky is host to some of the best double star systems visible without a telescope. Bring along some binoculars if you’re thinking about heading outside tonight - and read this article!
Photo Credit: Bob King (left) / ESO Digitized Survey (right)
Citizen Science - Get Involved with Galaxy Zoo



Modern Astronomy has produced so much data that astrophysicists are having a difficult time working through it all, and that’s why we need YOU.

The Galaxy Zoo project was launched in 2007 to open up the world of galactic science to everybody! Whether you’re an artist, writer, teacher, scientist, whatever - you can help. All you have to do is answer a few questions about a REAL IMAGE of a galaxy. Not only do you get to look at some of the most distant places in the universe, you also get to help humanity to better understand the universe!

Help science today!

photo credit: NASA and Galaxy Zoo

Messier Marathon on Tumblr!

Hey fellow tumblr scientists, astronomers, and space geeks!

I’m TheUniverseAtLarge and I’m going to be doing a big Messier Object Marathon over the next few months. Cool space images! Get excited!

What’s a Messier Object?

A Messier Object is a somewhat historical title for a particularly interesting object in the sky that was cataloged by French Astronomer Charles Messier in the 18th century. Messier was trying to find comets and when he found something in his telescope that wasn’t a comet nor a star, he would add it to his catalog so that he could keep track of “what wasn’t a comet”. His score:

Comets: 13

Galaxies, Nebulae, Clusters: 110*

So, was he really successful? I’d say not really. Messier is known more for not finding comets than finding comets. How would it feel to be famous for taking note of all your failures? Kinda funny, huh!

Keep your eyes on the astronomy tag or follow for a daily dose of the Messier universe!

Photo Credit:, Cambridge University Press

*some are re-observed or mistaken

How vast those Orbs must be, and how inconsiderable this Earth, the Theatre upon which all our mighty Designs, all our Navigations, and all our Wars are transacted, is when compared to them. A very fit consideration, and matter of Reflection, for those Kings and Princes who sacrifice the Lives of so many People, only to flatter their Ambition in being Masters of some pitiful corner of this small Spot.
Christiaan Huygens, Cosmotheoros