Serpens Constellation


Serpens constellation lies in the northern hemisphere. Its name means “the serpent” in Latin. It is one of the Greek constellations, first catalogued by the Greek astronomer Ptolemy in the 2nd century.

Serpens contains one of the most famous nebulas in the sky, the Eagle Nebula (Messier 16), which in turn contains the Pillars of Creation, a famous star-forming region.

Other notable deep sky objects in the constellation include the large globular cluster Messier 5, the emission nebula IC 4703, Seyfert’s Sextet of galaxies, the ring galaxy Hoag’s Object, the Red Square Nebula, and the Serpens South star cluster.

Serpens is divided into two parts by the constellation Ophiuchus, the snake bearer: Serpens Caput, representing the serpent’s head, and Serpens Cauda, the serpent’s tail.

FACTS, LOCATION & MAP

serpens constellation,serpens caput,serpens caput star map,serpens location

Serpens Caput Constellation Map, by IAU and Sky&Telescope magazine

Serpens is the 23rd constellation in size, occupying an area of 637 square degrees.

Serpens Caput, the western part of the constellation, representing the serpent’s head, is located in the third quadrant of the northern hemisphere (NQ3).

Serpens Cauda, the eastern part, representing the serpent’s tail, is found in the third quadrant of the southern hemisphere (SQ3).

The constellation can be seen at latitudes between +80° and -80°.

The constellations bordering Serpens Caput are Boötes, Corona Borealis, Hercules, Libra, Ophiuchus and Virgo.

serpens cauda constellation,serpens star map,serpens stars

Serpens Cauda Constellation Map, by IAU and Sky&Telescope magazine

The constellations bordering Serpens Cauda are Aquila, Ophiuchus, Sagittarius and Scutum.

Serpens contains two Messier objects – Messier 5 (M5, NGC 5904) and Messier 16 (M16, NGC 6611, Eagle Nebula) – and has nine stars with confirmed planets.

The brightest star in the constellation is Unukalhai, Alpha Serpentis, with an apparent visual magnitude of 2.63.

There are two daytime meteor showers associated with the constellation, both peaking between December 18 and 25: the Omega Serpentids and the Sigma Serpentids.

Serpens belongs to the Hercules family of constellations, along with Aquila, Ara, Centaurus, Corona Australis, Corvus, Crater, Crux, Cygnus, Hercules, Hydra, Lupus, Lyra, Ophiuchus, Sagitta, Scutum, Sextans, Triangulum Australe and Vulpecula.


MYTH

In Greek mythology, Serpens constellation represents a giant snake held by the healer Asclepius, represented by Ophiuchus constellation. Asclepius is usually depicted holding the top half of the snake in his left hand and the tail in his right hand.

Asclepius was the son of the god Apollo who was said to be able to bring people back from the dead with his healing powers.

In one of the stories, he killed a snake and saw it be brought back to life by a herb that another snake placed on it. It was said that Asclepius later used the same technique.

The brightest star in the constellation, Unukalhai (Alpha Serpentis), represents the serpent’s neck, and Alya (Theta Serpentis) marks the tip of the snake’s tail.

Serpens constellation dates back to Babylonian times. The Babylonians had two snake constellations. One represented a hybrid of a dragon, lion and bird and roughly corresponded to the constellation we know as Hydra, the water snake.

The other Babylonian constellation, called Bašmu, was depicted as a horned serpent, and loosely corresponded to the constellation Ὄφις, created by the Greek astronomer Eudoxus of Cnidus in the 4th century BC, on which Ptolemy’s Serpens constellation was based.

MAJOR STARS IN SERPENS

Unukalhai – α Serpentis (Alpha Serpentis)

Alpha Serpentis is the brightest star in the constellation. It has an apparent visual magnitude of 2.623 and is approximately 74 light years distant from the Sun. It is a double star located in the serpent’s head, Serpens Caput.

The primary component in the system is an orange giant with the stellar classification of K2 III. The star has a radius about 12 times solar and is 38 times more luminous than the Sun. The companion has a visual magnitude of 11.8 and is located at an angular separation of 58 seconds of arc. A 13th magnitude star can also be found in the vicinity, 2.3 arcminutes away.

The star’s traditional name, Unukalhai, is derived from the Arabic ‘Unuq al-Ħayyah, which means “the serpent’s neck.” The star is also sometimes known as Cor Serpentis, which is Latin for “the heart of the serpent.”

η Serpentis (Eta Serpentis)

Eta Serpentis is the second brightest star in the constellation. It is located in Serpens Cauda, the serpent’s tail. It is an orange star halfway between the subgiant and giant evolutionary stage. It has the stellar classification of K0 III-IV.

Eta Serpentis has an apparent visual magnitude of 3.260 and is approximately 60.5 light years distant from Earth. It has a mass double that of the Sun and a radius 5.897 times solar. It is 19 times more luminous than the Sun.

μ Serpentis (Mu Serpentis)

Mu Serpentis is a white main sequence dwarf with the stellar classification of A0V. It has an apparent magnitude of 3.54 and is about 156 light years distant from the solar system. It is the third brightest star in Serpens. It is located in Serpens Caput, the serpent’s head.

ξ Serpentis (Xi Serpentis)

Xi Serpentis is a triple star system about 105 light years from Earth. It has a visual magnitude of 3.54. The primary component in the system is a yellow-white giant with the stellar classification F0IIIp. It is a spectroscopic binary star with an orbital period of 2.29 days. The third component in the system is a 13th magnitude star located 25 arcseconds away from the main pair.

β Serpentis (Beta Serpentis)

Beta Serpentis is another multiple star system. It is located in Serpens Caput. It has an apparent visual magnitude of 3.65 and is approximately 153 light years distant from Earth. The system is a member of the Ursa Major Moving Group of stars. It has the stellar classification of A3V.

The main component in the system is a white main sequence star. The star has two companions, one with a visual magnitude of 9.9 located 31 arcseconds from the primary star, and another with a magnitude of 10.7, 201 arcseconds from the primary.

ε Serpentis (Epsilon Serpentis)

Epsilon Serpentis is another white main sequence dwarf, belonging to the spectral class A2Vm. It has an apparent visual magnitude of 3.71 and is 70.3 light years distant from Earth. The star is located in Serpens Caput. It has a radius 1.8 times solar and is 12 times more luminous than the Sun.

δ Serpentis (Delta Serpentis)

Delta Serpentis is another star system in Serpens Caput. It has a combined apparent magnitude of 3.80 and is about 210 light years distant from the solar system.

Delta Serpentis is composed of two binary stars separated by 66 seconds of arc. The primary component is a yellow white subgiant star with a visual magnitude of 4.2. The star is classified as a Delta Scuti type cariable, exhibiting variations in luminosity by 0.04 magnitudes with a period of 0.134 days. The star’s binary companion is also an F-type subgiant with an apparent visual magnitude of 5.2. The two stars are four arcseconds away from each other and have an orbital period of 3,200 years.

The second binary pair consists of a 14th magnitude star and a 15th magnitude binary companion separated by 4.4 seconds of arc.

γ Serpentis (Gamma Serpentis)

Gamma Serpentis is a yellow-white main sequence dwarf in Serpens Caput. It belongs to the spectral class F6 V. The star has an apparent visual magnitude of 3.85 and is approximately 36.3 light years distant from the solar system. It has a mass 1.30 times solar and a radius 1.55 times that of the Sun. It is 3.02 times more luminous than the Sun. The star is a suspected variable. It has two 10th magnitude optical companions.

κ Serpentis (Kappa Serpentis)

Kappa Serpens is a red giant of the spectral type M1III. It has an apparent magnitude of 4.09 and is about 348 light years distant from Earth. It is located in the serpent’s head, Serpens Caput.

ν Serpentis (Nu Serpentis)

Nu Serpentis is a binary star about 193 light years from Earth. It belongs to the spectral class A0/A1V. The primary component is a white main sequence dwarf with a visual magnitude of 4.32. The companion has a magnitude of 8.4 and is separated from the primary star by 46 seconds of arc.

λ Serpentis (Lambda Serpentis)

Lambda Serpentis is a yellow dwarf with the stellar classification of G0 V. It has an apparent visual magnitude of 4.43 and is 38.3 light years distant from the Sun. The star is a suspected variable. It has a mass 1.14 times that of the Sun and a radius 1.318 times solar. It is 1.94 times more luminous than the Sun.

The star is moving toward the Sun and, in about 166,000 years, it will come within 7.371 light years of the solar system.

Alya – θ Serpentis (Theta Serpentis)

Theta Serpentis is another multiple star system in Serpens. It has a combined apparent visual magnitude of 4.03 and is approximately 132 light years distant from the Sun. The star’s traditional name, Alya (sometimes Alga) is derived from the Arabic ’alyah, which means “the fat tail (of a sheep).”

Theta-1 and Theta-2 Serpentis are both main sequence dwarfs belonging to stellar classes A5V and A5Vn. The brighter component has a visual magnitude of 4.62 and Theta-2 has an apparent magnitude of 4.98. The stars are separated by 22 arcseconds in the sky, and have an orbital period of at least 14,000 years. The stars are 18 and 13 times more luminous than the Sun respectively, and both have masses and radii about twice solar, and surface temperatures of 8,000 kelvins.

The third component in the system is a yellow star of the spectral type G5, with a visual magnitude of 6.71. It is separated from Theta-2 Serpentis by 7 arcminutes.

R Serpentis

R Serpentis is a red giant with the stellar classification of M7IIIe. It is a Mira variable, a pulsating variable star very red in colour, that will expel its outer envelope to form a planetary nebula and become a white dwarf within a few million years.

R Serpentis has an apparent visual magnitude of 7.1 and is approximately 900 light years distant from the Sun.

χ Serpentis (Chi Serpentis)

Chi Serpentis is a white main sequence dwarf belonging to the spectral type A0p Sr. It has an apparent magnitude of 5.34 and is about 228 light years distant from the solar system.

The star is an Alpha-2 Canum Venaticorum type variable, a chemically peculiar star exhibiting magnitude variations by 0.03 over a period of 1.596 days.

τ Serpentis (Tau Serpentis)

Tau Serpentis is a Bayer designation shared by eight stars located in Serpens Caput.

Tau-1 Serpentis (9 Serpentis) is a red giant belonging to the spectral class M1III. It has a visual magnitude that ranges from 5.13 to 5.20, and is approximately 900 light years distant from the Sun. The star has a radius 54 times solar and an absolute magnitude of -2.1.

Tau-2 Serpentis (12 Serpentis) is a blue-white main sequence star of the spectral type B9V. It has an apparent magnitude of 6.218 and is about 430 light years distant from Earth.

Tau-3 Serpentis (15 Serpentis) is a yellow giant with the stellar classification of G8III. It has an apparent visual magnitude of 6.108 and is approximately 410 light years distant from the solar system.

Tau-4 Serpentis (17 Serpentis) is a red bright giant belonging to the spectral class M5II-III. It has a visual magnitude that varies from 5.89 to 7.07 with a period of about 100 days, and is classified as a semi-regular variable star. The star is approximately 520 light years distant from the Sun.

Tau-5 Serpentis (18 Serpentis) is a yellow-white main sequence dwarf of the spectral type F3V. It has an apparent visual magnitude of 5.938 and is approximately 160 light years distant from Earth. It has a mass 1.52 times solar.

Tau-6 Serpentis (19 Serpentis) is a yellow giant star with the stellar classification of G8III. It has a visual magnitude of 6.00 and is about 450 light years distant from the solar system. The star is a member of the Ursa Major Stream. It has a radius 11 times solar.

Tau-7 Serpentis (22 Serpentis) is a white star belonging to the spectral class A2m. It has an apparent magnitude of 5.804 and is about 174 light years distant from Earth.

Tau-8 Serpentis (26 Serpentis) is a white main sequence dwarf with the stellar classification of A0V. It has an apparent visual magnitude of 6.144 and is approximately 320 light years distant from the solar system. It has a radius double that of the Sun.

HD 168443

HD 168443 is a yellow main sequence star with the stellar classification of G5IV. It has a visual magnitude of 6.92 and is approximately 123.5 light years distant from the solar system.

The star has a confirmed planet and a brown dwarf in its orbit. The planet has a mass 7.696 times that of Jupiter and completes an orbit around the star every 58.116 days, while the brown dwarf has 17.378 times Jupiter’s mass and an orbital period of 1,739.5 days.

HD 136118

HD 136118 is a yellow-white dwarf with an apparent magnitude of 6.94, about 171 light years from Earth. It has the stellar classification of F9V.

The American astronomer Debra Fischer discovered a massive planet orbiting the star in February 2002. The object turned out to be a brown dwarf with a mass 42 times that of Jupiter. The dwarf has an orbital period of 1,209 days.

Gliese 710

Gliese is an orange main sequence dwarf with the stellar classification of K7 Vk. It has an apparent visual magnitude of 9.69 and is approximately 63.8 light years distant from Earth. The star is a suspected variable, with variations in magnitude ranging from 9.65 to 9.69. It has about 60 percent of the Sun’s mass and 67 percent of the solar radius.

Within the next 1.4 million years, the star will approach the Sun within a very small distance, possibly under one light year. When it does, it will be as bright as Antares, the brightest star in Scorpius constellation. The star’s proximity will have the potential to send a shower of comets into the solar system.

DEEP SKY OBJECTS IN SERPENS

messier 5,globular cluster,m5,ngc 5904

The globular cluster Messier 5 is one of the oldest belonging to the Milky Way. The majority of its stars formed more than 12 billion years ago, but there are some unexpected newcomers on the scene, adding some vitality to this aging population. Stars in globular clusters form in the same stellar nursery and grow old together. The most massive stars age quickly, exhausting their fuel supply in less than a million years, and end their lives in spectacular supernovae explosions. This process should have left the ancient cluster Messier 5 with only old, low-mass stars, which, as they have aged and cooled, have become red giants, while the oldest stars have evolved even further into blue horizontal branch stars. Yet astronomers have spotted many young, blue stars in this cluster, hiding amongst the much more luminous ancient stars. Astronomers think that these laggard youngsters, called blue stragglers, were created either by stellar collisions or by the transfer of mass between binary stars. Such events are easy to imagine in densely populated globular clusters, in which up to a few million stars are tightly packed together. Image: ESA, Hubble, NASA

Messier 5 (M5, NGC 5904)

Messier 5 is a globular cluster in Serpens constellation.

It has an apparent magnitude of 6.65 and is approximately 24,500 light years distant from Earth.

The cluster is about 80 light years in radius and can be seen without binoculars in extremely good conditions.

It is one of the larger globular clusters known.

The brightest stars in the cluster have an apparent magnitude of 12.2.

The cluster was discovered by the German astronomer Gottfried Kirch in 1702.

Charles Messier discovered it in 1764, but thought it was a nebula.

It was the German-born British astronomer William Herschel who was the first to resolve individual stars – about 200 of them – in 1791.

The cluster in fact contains over 100,000 stars, with some estimates counting as many as 500,000.

There are 105 known variable stars in M5, among them 97 known RR Lyrae variables.

The cluster has an estimated age of about 13 billion years, which makes it one of the older known clusters associated with our galaxy, the Milky Way.

eagle nebula,messier 16,m16,pillar of creation

The Eagle Nebula (Messier 16) – At the centre, the so-called “Pillars of Creation” can be seen. This wide-field image shows not only the central pillars, but also several others in the same star-forming region, as well as a huge number of stars in front of, in, or behind the Eagle Nebula. The cluster of bright stars to the upper right is NGC 6611, home to the massive and hot stars that illuminate the pillars. The “Spire” — another large pillar — is in the middle left of the image. Image: ESO

The Eagle Nebula – Messier 16 (M16, NGC 6611)

The Eagle Nebula, sometimes also known as the Star Queen Nebula, is a young open star cluster in Serpens.

It was discovered by the Swiss astronomer Jean-Philippe de Chéseaux in 1745-1746.

The shape of the cluster roughly resembles that of an eagle, which is how the cluster got its name.

The cluster contains the Pillars of Creation, a large region of star-formation that resembles a similar region in the Soul Nebula in Cassiopeia constellation.

The pillars were likely already destroyed by a supernova explosion believed to have occurred 8,000 to 9,000 years ago, but the image of the aftermath will not reach Earth for another 1,000 years or so.

Messier 16 is part of the diffuse emission nebula IC 4703.

star forming region,serpens constellation

Pillars of Creation in the Eagle Nebula, image: Hubblesite.org

IC 4703

IC 4703 is a magnitude 8 diffuse emission nebula, and an active star forming region, associated with the Eagle Nebula.

It is the nebula that surrounds Messier 16, which is in fact a cluster of stars.

IC 4703 is located in Serpens Cauda constellation.

The nebula is approximately 7,000 light years from Earth.

Seyfert’s Sextet – NGC 6027

Seyfert’s Sextet is a group of six galaxies in Serpens Caput constellation.

ngc 6027,galaxy group

Seyfert’s Sextet, image: NASA

Of these six, only four galaxies are physically related, while one is a background object, and another is in fact a separated part of one of the other galaxies that belongs to the group.

The four galaxies in the group are gravitationally interacting and will eventually merge to form a single giant elliptical galaxy.

Seyfert’s Sextet is approximately 190 million light years distant from Earth.

The group was named after the American astronomer Carl Keenan Seyfert, who discovered it in the 1950s. At the time, this was the most compact group of galaxies known.

NGC 6027 is a lenticular galaxy in Serpens. It is the brightest galaxy in Seyfert’s Sextet. The galaxy was discovered by the French astronomer Édouard Stephan in 1882. It has an apparent visual magnitude of 14.7 and is approximately 190 million light years distant from Earth.

NGC 6027a is a spiral galaxy with a visual magnitude of 14.9. The galaxy bears a strong resemblance to the Sombrero Galaxy (Messier 104) in Virgo constellation.

NGC 6027b has an apparent magnitude of 15.3. It is classified as a S0 peculiar galaxy.

NGC 6027c is another spiral galaxy. It has a visual magnitude of 16.7.

NGC 6027d is a spiral galaxy with an apparent magnitude of 16.5. It is not interacting with the other galaxies, but merely lies along the same line of sight, some 877 million light years from Earth.

red rectangle nebula

Red Square Nebula, image: NASA

NGC 6027e is a tidal tail of NGC 6027. It has an apparent magnitude of 16.7.

Red Square Nebula – MWC 922

The Red Square Nebula is a bipolar nebula in Serpens notable for its square shape.

It is one of the most symmetrical deep sky objects ever discovered.

It is unclear how the central star, MWC 922, produces the nebula’s shape.

ring galaxy

An image of Hoag’s Object, a non-typical galaxy of the type known as a ring galaxy, discovered in 1950 by astronomer Art Hoag, who initially thought it to be a planetary nebula. What appears to be an even more distant ring galaxy is plainly visible within the gap between this galaxy’s central body of mostly yellow stars and the outer ring of blue stars. Image: NASA

Hoag’s Object

Hoag’s Object is a ring galaxy in Serpens Caput.

It was named after the American astronomer Arthur Allen Hoag, who discovered it in 1950.

The galaxy has an apparent magnitude of 16.0 and is approximately 600 million light years distant from the solar system.

It has an almost perfect ring structure formed by young hot blue stars surrounding the older galaxy nucleus.

The inner core is about 17,000 light years in diameter, the surrounding ring is 75,000 light years in diameter, and the galaxy’s outer diameter spans 121,000 light years, which makes Hoag’s Object slightly larger than the Milky Way Galaxy.

Serpens South star cluster, image: NASA, JPL-Caltech, L. Allen (Harvard-Smithsonian CfA) & Gould's Belt Legacy Team

Serpens South star cluster, image: NASA, JPL-Caltech, L. Allen (Harvard-Smithsonian CfA) & Gould’s Belt Legacy Team

Serpens South star cluster

The Serpens South star cluster is a group of about 50 stars in Serpens constellation.

The cluster is approximately 848 light years distant from Earth.

35 stars in the cluster are protostars, only starting to take shape.

NGC 6539

NGC 6539 is a globular star cluster in Serpens constellation.

It has an apparent visual magnitude of 9.6 and is about 25,400 light years distant from Earth.

The cluster was discovered by the Danish astronomer Theodor Brorsen in 1856.

grand design galaxy,grand design spiral galaxy

NGC 6118, a grand-design spiral galaxy, shines bright in this image, displaying its central bar and tight spiral arms. The galaxy is sometimes known as the “Blinking Galaxy” because this relatively faint, fuzzy object would appear to flick into existence when viewed through their telescopes in a certain orientation, and then suddenly disappear again as the eye position shifted. The brilliant blue star-forming regions of the galaxy are beautifully illuminated, even from over 80 million light-years away. Image: ESO

Blinking Galaxy – NGC 6118

NGC 6118 is a grand design spiral galaxy in Serpens.

It has an apparent visual magnitude of 12.42 and is approximately 82.9 million light years distant from the solar system.

The galaxy is about 110,000 light years across, which makes it roughly the same size as the Milky Way.

NGC 6118 is a relatively faint object and not easy to observe with a small telescope.

It got the nickname the Blinking Galaxy because it tends to come in and out of view depending on the eye position.

A Type Ib supernova, SN2004dk, was discovered in the galaxy on August 1, 2004.

colliding galaxies,spiral galaxies

Arp 220 appears to be a single, odd-looking galaxy, but is in fact a nearby example of the aftermath of a collision between two spiral galaxies. It is the brightest of the three galactic mergers closest to Earth, about 250 million light-years away in the constellation of Serpens, the Serpent. The collision, which began about 700 million years ago, has sparked a cracking burst of star formation, resulting in about 200 huge star clusters in a packed, dusty region about 5,000 light-years across (about 5 percent of the Milky Way’s diameter). The amount of gas in this tiny region equals the amount of gas in the entire Milky Way Galaxy. The star clusters are the bluish-white bright knots visible in the Hubble image. Arp 220 glows brightest in infrared light and is an ultra-luminous infrared galaxy. Previous Hubble observations, taken in the infrared at a wavelength that looks through the dust, have uncovered the cores of the parent galaxies 1,200 light-years apart. Observations with NASA s Chandra X-ray Observatory have also revealed X-rays coming from both cores, indicating the presence of two supermassive black holes. Image: NASA, ESA, the Hubble Heritage (STScI, AURA)-ESA, Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville, NRAO, Stony Brook University)

Arp 220

Arp 220 is a deep sky object formed by a collision of two galaxies that are currently in the process of merging.

It is approximately 250 million light years distant and has an apparent visual magnitude of 13.9.

It is classified as an Ultraluminous Infrared Galaxy (ULIRG), and is the nearest one of its kind to Earth.

In October 2011, as many as 7 supernovae were observed in the galaxy at the same time.

NGC 5964

NGC 5964 is another spiral galaxy in Serpens Caput. It has an apparent visual magnitude of 12.6.

NGC 5970

NGC 5970 is a large barred spiral galaxy in Serpens Caput.

It has an apparent magnitude of 11.5 and is approximately 90 million light years distant from the solar system.

It appears face-on when observed from Earth.

The galaxy has two smaller satellites.

It lies about a degree to the southwest of the star Chi Serpentis.

NGC 5962

NGC 5962 is a spiral galaxy in Serpens Caput.

spiral galaxy,serpens caput

NGC 5962, image: Adam Block, Mount Lemmon SkyCenter, University of Arizona

With an apparent visual magnitude of 11.3, it is the brightest galaxy in the Serpens galaxy cluster.

The galaxy has a small central bulge and a relatively large core region.

It seems to have three smaller satellites, all dwarf galaxies.

NGC 5962 was discovered by the German-born British astronomer William Herschel in 1784 using a Newtonian reflector telescope.

NGC 5921

barred spiral galaxy

NGC 5921, image: Adam Block, Mount Lemmon SkyCenter, University of Arizona

NGC 5921 is a barred spiral galaxy in Serpens Caput.

It has an apparent visual magnitude of 11.5.

A supernova, SN 2001X, was observed in the galaxy in 2001.

Sh2-54

Sh2-54 is an extended bright emission nebula about 140 arcminutes in size.

ngc 6604,sh2-54,open cluster,emission nebula

The star cluster NGC 6604 is shown in this image taken by the Wide Field Imager attached to the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile. NGC 6604 is the bright grouping towards to the upper left of the image. It is a young star cluster that is the densest part of a more widely scattered association containing about one hundred brilliant blue-white stars. The picture also shows the cluster’s associated nebula — a cloud of glowing hydrogen gas that is called Sh2-54 — as well as dust clouds. Image: ESO

The core region of the nebula contains many infrared sources and many protostars, large masses formed as a result of contraction of gas, that will eventually become stars.

The older stars in the nebula are estimated to be 4-5 million years old, and form the open cluster NGC 6604.

The nebula is approximately 6,200 light years distant from the solar system.

It is part of an extended nebulous region which also includes the Eagle Nebula and the Omega Nebula in Sagittarius constellation.

NGC 6604

NGC 6604 is an open cluster in Serpens, located about 2 degrees to the north of the Eagle Nebula.

It has an apparent visual magnitude of 6.5 and is approximately 5,500 light years distant from Earth.

IC 4756

IC 4756 is an open star cluster in Serpens.

It is approximately 1,300 light years distant from the solar system.

Palomar 5

Palomar 5 is another globular cluster in Serpens. It has an apparent visual magnitude of 11.75 and is approximately 76,000 light years distant from the solar system.

The cluster is about 76 light years in radius.

It was discovered by the German astronomer Walter Baade in 1950 and then independently discovered by the American astronomer Albert George Wilson in 1955.