Thursday, October 30, 2008

Haunted Sky

It is with ghoulish pleasure that I present you with 13 spine-tingling Halloween treats— of a celestial nature. There’s something here for everyone: naked-eye stargazers, telescope observers, and armchair astronomers who just want their eyeballs exquisitely tortured with devilishly detailed astronomical imagery.

Keep reading, but only if you’re brave enough to whistle in a stellar graveyard.

1) The Coffin (naked eye)
Hanging just above the western horizon after sunset— and northwest of bright Jupiter— is the summer constellation Ophiuchus (oh-fee-YOU-kuss) the Serpent Handler. A number of the brightest stars in this constellation form the asterism (recognizable star pattern) called the Coffin, which looks like an old-fashioned casket with a pointed head.

Star maps created with Your Sky


2) Little Ghost Nebula NGC6369 (armchair)
This faint planetary nebula in Ophiuchus currently trails just behind Venus. A planetary nebula is a dying star, that is, it’s the stellar material (gas and dust) being puffed off during a moderate-sized star’s death throes.

Normally, a medium- to large-aperture (diameter) telescope is required to view the Little Ghost. However, it’s currently too low in the west after dark to get a good view. Find bright Venus in the western sky at sunset, and imagine the Little Ghost floating right behind her. Then just stare zombie-like at this beguiling image taken by the Hubble Space Telescope.

Little Ghost Nebula
Source: NASA and The Hubble Heritage Team (STScI/AURA)



3) Snake Nebula B72 (armchair)
This tortuous dark nebula in Ophiuchus is just west of the Little Ghost. A dark nebula is a dense interstellar cloud that obscures light from the stars behind it. To the observer, it looks deceivingly like a void in space. In this case, the Snake is obscuring the rich star fields of the Summer Milky Way.

Although the Snake Nebula can be viewed telescopically, it’s currently too low in the west after dark to be visible. Your consolation prize is this image that practically hisses.

Snake Nebula
Source: Tom McQuillan/Adam Block/NOAO/AURA/NSF


4) Ghost of a Cheerio M57 (telescope)
This alternate name for the Ring Nebula perfectly describes the planetary nebula’s spectral, smoke ring appearance. It can be viewed satisfactorily in even a small telescope. However, you’ll need substantial aperture, a dark sky, and a good eye to spot the faint central star that’s dying and throwing off all the ghostly material.

Look for M57 in Lyra the Harp, south of the Summer Triangle star Vega.



5) Job’s Coffin (naked eye)
High overhead in the little constellation Delphinus (dell-FINE-uss) the Dolphin is the asterism known as Job’s Coffin, a quadrilateral of four stars. Look for the Dolphin sandwiched between two geometrical shapes: east of the Summer Triangle and west of the Great Square of Pegasus.




6) Cocoon Nebula IC5146 (armchair)
North of the Dolphin in the constellation Cygnus the Swan, near the bright Summer Triangle star Deneb, is the mysterious Cocoon Nebula. This large diffuse nebula is a stellar nursery, a cloud of gas and dust where new stars are forming. Because of its low surface brightness, it’s a very challenging object to observe and is perhaps best left to the seasoned observers with large-aperture telescopes. As for the rest of us, let’s ponder what else might be hatching in that cocoon while we examine this image taken at Kitt Peak Observatory.

Cocoon Nebula
Source: Julie and Jessica Garcia/Adam Block/NOAO/AURA/NSF



7) Demon Star (naked eye)
Face north. Rising in the northeast is the constellation Perseus the Hero, which contains the notorious variable star Algol, aka the Demon Star or the Ghoul Star. Algol is a double star, and its orbiting companion star eclipses it like clockwork every 2.8 days. This makes Algol’s brightness dip suddenly and dramatically. Perhaps this eerie effect is what led the ancient Greeks to consider Algol the decapitated head of Medusa, being brandished by her slayer, Perseus. Medusa was the snake-haired creature whose frightful appearance turned anyone who looked upon her to stone. Look for Perseus just northeast of the Lazy W asterism of Cassiopeia.



8) Cat’s Eye Nebula NGC6543 (telescope)
Still facing north, you’ll find the Cat’s Eye, another planetary nebula, just northeast of the Lozenge, the asterism that marks the head of the constellation Draco the Dragon. The Cat’s Eye is a telescopic heart-thumper due to its spellbinding aqua color. Once you find the “eye,” imagine the cosmic black cat it might belong to.



9) Skull Nebula NGC246 (telescope)
Just north of Diphda (DIFF-duh), the brightest star in the constellation Cetus the Whale, is the planetary nebula known as the Skull. Here’s a Halloween trick: if your scope doesn’t pull in enough of the nebulosity to give you the skull effect, focus on the triangle of three bright stars that could be two glowing eyes and a nose. With the surrounding wisps of nebulosity giving shape to a head, the object becomes the face of a wolf. Or perhaps a werewolf?

Nebula as skull

Nebula as wolf


10) Witch Head Nebula IC 2118 (armchair)
The Witch Head is technically in the constellation Eridanus the River, however, it’s easier to think of it located just to the right of Rigel, the brightest star in the constellation Orion and the one that marks the Hunter’s left foot. In fact, light from supergiant Rigel is what’s illuminating the nebula’s dust particles and making them glow. You’ll find Orion the Hunter well up over the eastern horizon before midnight.

This diffuse nebula is immense and faint. Like the Cocoon Nebula (#6), this one’s not for the faint of heart or the small of aperture. Best we keep our distance from the gnarly-faced witch and simply gaze at her profile in this image by astrophotographer John Sefick.

Witch Head Nebula


11) The Sickle (naked eye)
A couple hours after midnight, this stand-out asterism in the constellation Leo the Lion will have risen above the eastern horizon. The Sickle looks like both a backwards question mark and the farming implement traditionally brandished by the Grim Reaper.




12) Ghost of Jupiter NGC3242 (telescope)
The bottom of the Sickle points toward this planetary nebula in the constellation Hydra the Water Snake. It should be viewable in most telescopes and will appear as a dim bluish orb. It was nicknamed the Ghost of Jupiter because, in a telescope, it has about the same apparent size as the planet. Apparent size is the amount of sky an object covers from our perspective on Earth.

Ghost of Jupiter


13) Tarantula Nebula 30 Doradus (armchair)
This Southern Hemisphere object isn’t visible to us Northerners, and it’s not even in the Milky Way, but it’s simply too creepy not to include. It’s actually a gargantuan star-forming nebula in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way. However, its fuzzy “spider legs” of gas and dust make it the perfect Number 13 for this list.

Have a boo-dacious Halloween.

Tarantula Nebula

Thursday, October 23, 2008

Lady in Chains

The constellation of Andromeda the Chained Woman is one of the premiere sights of the autumn sky. In Greek mythology, Andromeda (ann-DROMM-eh-duh) was the daughter of King Cepheus (SEE-fee-yuss) and Queen Cassiopeia (kass-ee-oh-PEE-yuh). Because the insufferably vain Cassiopeia offended the gods, Andromeda was chained to a rock by the sea as an offering to the sea monster Cetus (SEE-tuss).


The Royal Family: Cepheus, Cassiopeia, Andromeda & Perseus
Star maps created with
Your Sky


Cassiopeia the Queen, Cepheus the King, Andromeda, and Andromeda’s rescuer and subsequent husband, Perseus the Hero, are all immortalized in the night sky as constellations. The four star groups are known collectively as the Royal Family. They can be observed together in the night sky after sunset, in fall and winter. Also lurking nearby, through early winter, is the constellation Cetus the Sea Monster, aka Cetus the Whale.

Let’s take a closer look at the stars of our damsel in distress.

1) Wait at least one hour after sunset to begin observing, so that twilight’s faded and your sky’s good and dark.

2) Since we’re approaching New Moon on October 28th, you’ll have plenty of dark hours to observe before the Moon rises.

3) Face east. If you don’t know the cardinal directions at your location and you don’t have a compass, make note of where the sun sets on the horizon. That spot is approximately west. Stand with your back to the west, and you’ll be facing approximately east.




4) First find the Great Square of Pegasus, about halfway between the zenith (the point in the sky directly above your head) and the eastern horizon. The Great Square is an asterism, a recognizable star pattern, within the constellation Pegasus. It's defined by four bright stars, one at each corner. Each side of the Square is about one and a half to two fists wide, if you hold your fist at arm’s length against the sky and measure across the widest part.

5) From the corner star that is farthest north, look for two chains of stars curving north. Not counting the corner star, there are three bright stars in each chain.




6) The corner star, although part of the Great Square asterism, is technically in Andromeda. Its name, Alpheratz (AL-fuh-rats) sounds like a lab experiment gone terribly wrong, but it’s Arabic for horse’s shoulder, a reference to Pegasus.

Along the lower chain— the one closest to the eastern horizon— the star to the left of Alpheratz has no traditional name, so we call it Delta, its star catalog designation. Next in line is Mirach (MIRR-ahk), Arabic for girdle. Mirach and Alpheratz are tied for the title of brightest star in Andromeda. Mirach is a red giant; compare it visually to blue Alpheratz. Can you see the difference in hue?

Last in line on the lower chain is Almach (ALL-mahk). Almach is from the Arabic for caracal, a nocturnal cat found in Africa and Asia.

7) Let’s jump to the upper chain, again starting at Alpheratz and moving left. All three stars of the upper chain have no traditional names, so we use their star catalog designations and call them Pi, Mu, and the exceptionally picturesque 51 Andromeda. Honestly, was there no one in the whole of antiquity who could come up with an appropriate name for the star marking the maiden’s royal right foot?


The Chained Woman, from Johann Bode's 1801 star atlas


I imagine the celestial princess finds it undignified enough that her left foot is permanently associated with a reclusive predator with rodent breath. Maybe it’s been eating those alpha rats.

Thursday, October 16, 2008

The Little Dolphin

Just east of Altair, the southernmost star in the Summer Triangle, is Delphinus the Dolphin. Although a rather small, unassuming constellation, its distinctive central asterism (recognizable star pattern) actually resembles a leaping dolphin, so it’s fairly easy to spot once you’ve learned it.


Image from Flamsteed’s 18th century star atlas
Courtesy of
Linda Hall Library of Science, Engineering and Technology


Delphinus the Dolphin (dell-FINE-uss) is an ancient constellation. In Greek myth, Delphinus was a messenger of the sea god Poseidon. When Poseidon pressed one of the sea nymphs at his court to marry him, the reluctant goddess fled. The persistent Poseidon sent a number of messengers to persuade her to return and become his wife, but only the beguiling dolphin succeeded. A grateful Poseidon elevated Delphinus to immortality in the night sky.


Star maps created with Your Sky


When I see the jeweled spray of stars that forms the Dolphin asterism high overhead in the early evening, I know that autumn has arrived. Let’s take a closer look at those five stars.

1) If you don’t know how to locate the Summer Triangle, read my earlier post. Look for the sprightly Dolphin a little east of Altair, the brightest star in Aquila the Eagle.


Dolphin asterism in the constellation Delphinus


2) Yellow-white Rotanev (ROH-tuh-nev) is the brightest star in Delphinus. Although slightly dimmer than Rotanev, blue-white Sualocin (SWAH-loh-sinn) is nevertheless the hotter of the two.

When these star names first appeared in an Italian star catalog in 1814, astronomers were puzzled as to their origin. Clever sleuthing by the English astronomer Thomas Webb revealed them to be the reverse spelling of Nicolaus Venator, the Latinized version of the name Niccolo Cacciatore. Cacciatore was the assistant to (and successor to) Giuseppe Piazzi, the famed director of the Palermo Observatory in Italy. It is unclear whether Cacciatore or Piazzi was responsible for the stellar wordplay.

Giuseppe Piazzi is best known as the discoverer of the largest asteroid found in our solar system to date: Ceres (SEER-eez).

3) The other two stars that, along with Rotanev and Sualocin, complete the “head” of the Dolphin asterism have no traditional names, so we call them Gamma and Delta, their star catalog designations. Gamma is a yellow-orange star, and Delta is a white giant.

4) The blue-white giant star that marks the dolphin’s tail is Deneb al Dulfim (DENN-ebb), from the Arabic for, blimey, dolphin’s tail! Now can you see the dolphin frolicking in the foam of the Summer Milky Way?




5) Delphinus contains an asterism within an asterism. The head of the Dolphin asterism— the quadrilateral formed by Rotanev, Sualocin, Gamma, and Delta— is an asterism known as Job’s Coffin. The origin of this odd name is unknown. It’s just another mystery lost to history. Perhaps someone should have put Thomas Webb on the case.

Thursday, October 9, 2008

It's a Bird!

The days of the month surrounding Full Moon can sometimes feel like an astronomical “dead zone.” The floodlight effect of our lunar neighbor on the night sky makes everything from tracing out naked-eye star patterns to telescopic viewing of deep-sky objects difficult to impossible.

Certainly you can enjoy looking at the Moon itself. There are interesting craters to behold with your binoculars or telescope. Naked-eye moongazers with an extra dollop of imagination can look for pareidolia among the Moon’s dark maria or “seas.”

But here’s another diversion for those suffering from Full Moon fever: satellite watching. Many satellites are naked-eye targets, they’re generally bright enough to be seen on moonlit nights, and they travel in predictable orbits. What could be easier?


Image source: NASA


Satellites, colloquially known as “birds,” are man-made objects in orbit around Earth. Typically, they are unmanned communications, navigation, and observation stations. One notable unmanned craft is the Hubble Space Telescope, which regularly returns remarkable, detailed images of celestial objects, for scientific study and public enjoyment.

Some satellites are simply large pieces of space junk. These may include stations that are no longer operational but which continue to circle the planet until their orbits deteriorate, they enter Earth’s atmosphere, and they vaporize before impact (hopefully). Space junk may also include objects that have been jettisoned from manned craft.

Which brings us to the manned station circling the planet: the International Space Station (ISS). The ISS is a 16-country international collaboration: proof positive that human beings can work together for the advancement of the entire human race. This engineering marvel, with a resident multi-national crew on board, completes an Earth orbit every 90 minutes.



International Space Station
Image source: NASA


By the way, the word “satellite” is also used in astronomy as a synonym for “moon,” as in, “Saturn has 34 satellites.” The Moon is sometimes referred to as a natural satellite of Earth.


Image source: NASA


There are two terrific websites that can help you get started with man-made satellite watching. The first one I’ll mention, because it’s the easiest for beginners to use, is Satellite Tracker by spaceweather.com. Simply enter your zip code on the home page, click the “Go” button, and you’ll get a list of the best-and-brightest satellite flybys in your area over the next ten days. For each flyby, the rise time (when the satellite first appears over the horizon) and the transit time (when the satellite is at its highest in the sky) are both given in your local time. Nope, you won’t have to do any pesky conversions.

You’ll also be given the compass direction in which to look, as well as the predicted magnitude (brightness) of the satellite. You may recall from my previous discussion of the star Vega that objects with negative-number magnitudes are brighter than objects with positive-number magnitudes. However, you don’t need to remember that to use this website; the magnitude is also characterized for you as “very bright,” “visible,” or “dim.” Start with the satellites labeled “very bright,” as you’ll have the best chance of success with these. Once you have a few bright flybys under your belt, work your way up to the “visible” and “dim” objects.

Keep in mind that you’ll only see low-flying satellites such as the ISS (~250 miles above Earth) and the Hubble Space Telescope (~350 miles above Earth) shortly after sunset or shortly before sunrise. Satellites are visible to us only when they’re reflecting sunlight. A low-orbit satellite passing overhead in the dead of night would be in Earth’s shadow, with the Sun on the other side of the planet and no way to receive light from it.



Hubble Space Telescope
Image source: NASA


How can we tell a satellite from a plane? A satellite moves in a straight line and is usually visible for only a few minutes before winking out. A plane will typically be visible for longer, and you may see directional change. Also, a plane will usually have flashing lights and/or colored lights. If it’s close enough and the observing environment quiet enough, you’ll hear the plane’s engine(s). Satellites are silent. Several lights moving in formation are often military craft performing maneuvers.

The second website I’d like to recommend, for intermediate and advanced observers, is Heavens Above. On the home page, select your current observing site “from database” by selecting your country and typing in your town name. When it appears on the search results, click your town name to select it as your location. Then in the “Satellites” section, request your desired satellite predictions. This site also gives you pass results in local time, but it’s expressed in military time. I don’t know about you, but I don’t think in military time. Points taken off for making me do a pesky conversion!

Heavens Above gives prediction data for many more satellites than the Satellite Tracker site, and you can also request data for a specific satellite from their large database. Plus, the website offers much more than just satellite data. The “Astronomy” section has current data about visible comets and asteroids, and lots more.



On the evening of October 8, I took a last gulp of ice tea and hurried out of my local diner with four minutes to spare before a scheduled ISS pass. Soon, my partner, two other customers, a waitress, and a cook joined me in the parking lot to scan the northwestern horizon for the first appearance of the Space Station. Satellite spotting is a great activity to share with adults and kids, friends and perfect strangers.

We had a few false alarms as planes appeared over the horizon, heading for the international airport nearby. One of the customers was the first to whoop, “There it is!” Then we all spotted it, a steadily moving light already well above the horizon. The cook scurried back inside to flip some burgers and answer the phone, while the rest of us watched it climb and waved to the unseen crew inside.

Shortly after it reached the highest point of the pass, the reflected sunlight from the satellite became ruddy-colored. It was sunset on the ISS. From the astronauts’ vantage point as they rounded Earth, the Sun was sinking below Earth’s horizon. Then the satellite was swallowed by Earth’s shadow, and the light winked out.

Just think: if you were a sleepless astronaut on the ISS, over the course of 24 hours you could watch the Sun rise and set many times. Busy old fool, the poet called him.

…since thy duties be
To warm the world, that’s done in warming us.
Shine here to us, and thou art everywhere;
This bed thy center is, these walls thy sphere.
from The Sun Rising, by John Donne

Thursday, October 2, 2008

Triangle

Although autumn is beginning to nip the air and sweaters are starting to replace tank tops, you can still hold on to that endless-summer feeling a little longer. If you look up after sunset, you’ll find the star pattern known as the Summer Triangle overhead. Like the Winter Hexagon, the Summer Triangle is a seasonal asterism (recognizable star pattern) that spans more than one constellation.

Even in somewhat light-polluted areas, you should be able to spot the three bright stars that define the Triangle, but this asterism is worth a trip to the outskirts of town to view it under dark skies. The Triangle has naked-eye and binocular treasures to plunder, if you’re willing to go the extra mile.

Once you master the Summer Triangle, you will know:
- five constellations
- the brightest stars in three of those constellations
- which star is used as the standard for star brightness
- the direction in which our solar system is traveling
- another prominent asterism
- a notable double star
- a naked-eye star cluster
- a binocular star cluster

This is a great deal. In fact, just think of this as a celestial end-of-summer closeout sale. Hurry hurry hurry!

1) Wait at least one hour after sunset to begin observing, so that twilight’s finished and your sky’s good and dark.

2) Check the time of moonset before you observe. The waxing (growing) Moon will be in the western sky at sunset and will set a bit later than the night before, each night this week. The Moon will also be a bit brighter each night, as the illuminated part of its face increases. Your optimum observing window— for least Moon interference and best placement of the Triangle in the sky after moonset— ends on Sunday night, October 5.

3) Face south. If you don’t know the cardinal directions at your location and you don’t have a compass, make note of where the sun sets on the horizon. That spot is approximately west. Stand with your right shoulder to the west, and you’ll be facing approximately south.



Star maps created with Your Sky


4) Tilt your head all the way back until you're looking at the zenith, the point in the sky that’s directly overhead. Now look for a large triangle formed by three bright stars. It will straddle the zenith or be slightly south of it, depending on your latitude. The sides of the triangle will be two to three fist-widths long. A fist-width is defined here as your fist held at arm’s length against the sky and measured across the knuckles.

5) The stars that mark the points of the triangle are Vega (VAY-guh) in the constellation Lyra the Harp (LYE-ruh), Altair (AHL-tair) in the constellation Aquila the Eagle (uh-QUILL-uh), and Deneb (DENN-ebb) in the constellation Cygnus the Swan (SIGG-nuss).

Vega is Arabic for swooping vulture, Altair is Arabic for flying eagle, and Deneb is Arabic for hen’s tail. Let’s see, Aquila is an eagle, and Cygnus is a swan. Yes, there’s an ornithological motif here, with its roots entwined in the ancient star lore of several cultures.





6) Be careful to identify the correct triangle. It’s possible to be distracted by Rasalhague (RAH-sahl-hayg), the brightest star in neighboring Ophiuchus (oh-fee-YOU-kuss) the Serpent Handler, and to combine it with Vega and Altair. However, Rasalhague is farther west than the three Triangle stars, and it’s not as bright as Deneb.






Another way to ensure you have the correct triangle, with Deneb, is to look for the asterism called the Northern Cross. Deneb is at the top of the cross, and the bottom of the cross terminates inside the Triangle, nearly equidistant from Vega and Altair.

7) Now that you’re sure you’ve found the Triangle, let’s take a closer look at the point stars.

Vega, a white dwarf, is the brightest star in Lyra the Harp and the fifth brightest star in the night sky. Apparent magnitude, how bright a star appears to us from Earth, is one of the ways in which stars are measured, categorized, and compared. Vega is a zero magnitude star, and it’s the standard of brightness to which all other stars are compared. Dimmer stars have a magnitude expressed with a positive number, while stars brighter than Vega have a magnitude expressed with a negative number. It’s just the opposite of how you’d think it would be.

A light year is the distance light travels in one Earth year, nearly six trillion miles. Vega lies 25 light years from Earth, and it just happens to lie close to the solar apex. The solar apex is the point in the night sky toward which our solar system appears to be heading, as it travels around the center of the Milky Way galaxy in a 225-million-year-long orbit.





Altair, also a white dwarf, is the brightest star in Aquila the Eagle. Altair is flanked evenly by two dimmer stars, Alshain (all-SHANE) and Tarazed (TAH-ruh-zedd). The names of both stars are from a Persian phrase meaning scale beam, that is, the balance bar from which a set of scales hangs. This straight line of three stars is easy to pick out in the night sky. In old star atlases, Altair marked the heart of the Eagle. Altair is about 16 light years from Earth, the closest of the three Triangle stars.

Deneb, a white supergiant 200 times the size of our Sun, is the brightest star in Cygnus the Swan. Deneb marks the tail of the Swan, and as we learned earlier, the top of the Northern Cross.

In reality, spectacular Deneb is considerably brighter than either Vega or Altair. It appears to us the dimmest of the three because of its great distance. It’s 2600 light years away— that’s 2600 times six trillion miles. It may be forgiven if its light is a bit weak after that long journey to our eyes.






8) In addition to Lyra, Aquila, and Cygnus, the Triangle also encompasses parts of two minor constellations: Vulpecula the Fox (vull-PECK-you-luh) and Sagitta the Arrow (suh-JEE-tuh). The map above shows the modern boundaries of these obscure old constellations. Don’t worry about identifying the specific stars of these constellations inside the Triangle; it’s enough to know that they’re there.

When the Fox was introduced to star atlases in the 17th century, he was depicted carrying in his jaws a goose. Yet another species for our celestial birdwatching list!





9) Earlier we identified the Northern Cross asterism. The star at the bottom of the Cross, inside the Triangle, is the showy double star Albireo (al-BEER-ee-yoh). Albireo marks the beak of the Swan. Now that you know the location of the beak and tail of the Swan, you can extend the crosspiece of the Northern Cross on either side to visualize the Swan’s outstretched wings.

Albireo is commonly known as the Cub Scout Star. To discover why, you’ll need to examine it through binoculars, 10x50s or larger. Use your binoculars on a tripod if you have one. If not, steady your arms by propping them on a fencepost or other stable object. With sharp focus, you should see a bright gold star with a dimmer blue star nearly touching it. Blue and gold: the Cub Scout colors.

Albireo is a visual double, that is, two stars that appear to be close together but in fact aren’t in proximity and aren’t interacting. Space is three dimensional, and that depth creates many pleasing— albeit deceptive— star pairings, as seen from our earthly vantage point.





10) Now draw an imaginary line between Altair in Aquila and Vega in Lyra. About a third of the way from Altair to Vega is a naked-eye object called Brocchi’s Cluster. Can you see the sparkly patch of light? The object is named for the amateur astronomer who mapped it in the 1920s, although it’s been known since antiquity. Despite its name, it probably isn’t a true star cluster, since its stars don't seem to be related. Rather it’s an asterism, a chance arrangement of stars forming a recognizable pattern.

That pattern is revealed when you view the object through binoculars, as is its other name: the Coathanger. Magnified, the patch is transformed into a whimsical star grouping that resembles a coat hanger. A foxy trick, perhaps, but then the Coathanger does lie in the constellation of Vulpecula the Fox.



The Coathanger
© T. Credner & S. Kohle, AlltheSky.com


11) Speaking of foxes, let’s find our final target, one of my favorite star clusters: the charming Foxhead Cluster in Cygnus. You’ll need good-sized binoculars for this one; I’d recommend 10x50s or larger. Draw an imaginary line from Vega in Lyra to Sadr in Cygnus. Sadr (SAH-durr) is the star at the center of the Northern Cross. Train your binoculars on a spot that’s a little more than halfway from Vega to Sadr. Look for a triangle-shaped clutch of stars with two bright stars flanking it. The triangular cluster is the Foxhead, and the longer you look at it, the more it begins to resemble the pointed snout and ears of a fox. An overactive imagination can be a great advantage in this endeavor.


The Foxhead Cluster
Image from Sloan Digital Sky Survey



With all those birds flitting around the Triangle, I imagine this wily fox is just biding his time.

12) You hopefully have noticed the long, bright “cloud” of the Summer Milky Way running through the Triangle. The glowing band is a sort of celestial runway for Cygnus the Swan, who appears to be preparing to fly south for the winter.

The Summer Milky Way is our edge-on view of the star-packed arms of our platter-shaped galaxy. In the summer, due to Earth’s location in its orbit around the Sun, we are looking inward, towards the galactic core.

How exciting that we can see, with our naked eyes, some of the structure of that vast star system to which our lucky old Sun— and we— belong.