Some people might say, “How can you get so excited about a little grey smudge?” My answer is because that little grey smudge is over ONE BILLION LIGHT YEARS AWAY!!! It is the farthest object I have ever seen with my telescope!
I went stargazing on April 18, 2024. It is usually cloudy in April so when we had a week of great weather, I knew I had to take advantage of it. I brought with me a copy of an article from Sky and Telescope magazine that listed more than a dozen galaxies that are over a billion light years away from us. I wanted to try to see and photograph one. My first few attempts were failures but then I tried NGC 3908.
NGC 3908 is so faint and so distant that it is not in the eVScope database so I had to look up the galaxy’s celestial coordinates and enter that raw data into the telescope’s navigation feature to get the scope to look for NGC 3908. After a few minutes of light accumulation, a faint grey smudge started to appear in the center of my image.
I was not sure that I was actually seeing the NGC 3908 galaxy. I was seeing something in the center of my image and that is where objects are supposed to appear. I could tell it was not a star. It could have been a far distant star cluster, but I didn’t think so. I was just hoping this was more than just random schmutz on my photo. I had to wait until I got home to find out for sure. I uploaded my image to a website called Astrometry.net. This website analyzes astronomical images and identifies the deep sky objects that are in the picture. The analysis from Astrometry.net confirmed that my grey smudge is in fact NGC 3908. I had done it!
(See below for the image and to learn more about NGC 3908.)
Galaxies
Here is my new favorite galaxy; NGC 3908. Like I said before, all you can see in the image is a faint grey smudge in the center of the picture, so I put a red circle around it to make it easier for you to find. Another oft repeat piece of advice is that you may need a large monitor or you may need to zoom in on the image to see the galaxy.
NGC 3908 is one of the furthest NGC objects. It is an elliptical galaxy located 1.2 billion light-years away in the Leo constellation with an estimated 280,000 light-years across in diameter. It is one of the biggest and brightest galaxies in its galactic cluster. It was discovered on April 10, 1885, by Lewis Swift, who found the object too faint for the naked eye to see because of its distance from us. Due to its relatively large size, NGC 3908 is considered a brightest cluster galaxy, a BCG.
The Sombrero Galaxy (also known as Messier Object 104, M104 or NGC 4594) is a peculiar galaxy of unclear classification in the constellation borders of Virgo the Maiden and Corvus the Crow, being about 9.55 megaparsecs (31.1 million light-years) from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has a diameter of approximately 29.09 to 32.32 kiloparsecs (94,900 to 105,000 light-years), making it slightly bigger in size than the Milky Way.
It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its outer disk, which is viewed almost edge-on. The dark dust lane and the bulge give it the appearance of a sombrero hat (thus the name). Astronomers initially thought the halo was small and light, indicative of a spiral galaxy; but the Spitzer Space Telescope found that the dust ring was larger and more massive than previously thought, indicative of a giant elliptical galaxy.
The galaxy has an apparent magnitude of +8.0, making it easily visible with amateur telescopes, and is considered by some authors to be the galaxy with the highest absolute magnitude within a radius of 10 megaparsecs of the Milky Way. Its large bulge, central supermassive black hole, and dust lane all attract the attention of professional astronomers.
Messier 49 (also known as M49 or NGC 4472) is a giant elliptical galaxy about 56 million light-years away in the equatorial constellation of Virgo. This galaxy was discovered by astronomer Charles Messier in 1777. As an elliptical galaxy, Messier 49 has the physical form of a radio galaxy, but it only has the radio emission of a normal galaxy.
This galaxy has many globular clusters: estimated to be about 5,900. This is far more than the roughly 200 orbiting the Milky Way, but dwarfed by the 13,450 orbiting the supergiant elliptical galaxy Messier 87. Messier 49 was the first member of the Virgo Cluster of galaxies to be discovered. It is the most luminous member of that cluster and more luminous than any galaxy closer to the Earth.
Messier 98, M98 or NGC 4192, is an intermediate spiral galaxy about 44.4 million light-years away in slightly northerly Coma Berenices, about 6° to the east of the bright star Denebola (Beta Leonis). It was discovered by French astronomer Pierre Méchain on 1781, along with nearby M99 and M100, and was catalogued by compatriot Charles Messier 29 days later in his Catalogue des Nébuleuses & des amas d'Étoiles.
It is a spiral galaxy that displays mixed barred and non-barred features with intermediate to tightly wound arms and no ring. The combined mass of the stars in this galaxy is an estimated 76 billion (7.6 × 1010) times the mass of the Sun. Messier 98 is a member of the Virgo Cluster, which is a large cluster of galaxies, part of the local supercluster. About 750 million years ago, it may have interacted with the large spiral galaxy Messier 99. These are now separated by 1,300,000 ly (400,000 pc).
Nebulae
I was not able to find any new, interesting nebulae to include in this blog post so I decided to include a few of the more impressive nebulae from previous blog posts.
This picture of the Horsehead Nebula took 25 minutes to get. While this picture is definitely better than the previous photo (3-minute exposure), it is still faint. You can see more of the red haze that defines the dark nebula that makes up the horsehead. The head is dark and in the center of the picture. The head is facing up. It is surrounded by a faint, red glow that “highlights” the head.
The Horsehead Nebula is a small dark nebula in the constellation located just to the south of Alnitak, the easternmost star of Orion's Belt, and is near the Flame Nebula. It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of a much larger, active star-forming region. The Horsehead Nebula is approximately 1,375 light-years from Earth.
The Lagoon Nebula (catalogued as Messier 8 or M8, NGC 6523, Sharpless 25, RCW 146, and Gum 72) is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula. The Lagoon Nebula was discovered by Giovanni Hodierna before 1654 and is one of only two star-forming nebulae faintly visible to the eye from mid-northern latitudes. Seen with binoculars, it appears as a distinct cloud-like patch with a definite core. Within the nebula is the open cluster NGC 6530. The Lagoon Nebula is estimated to be between 4,000–6,000 light-years away from the Earth.
The Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, Lobster Nebula, and the Horseshoe Nebula (catalogued as Messier 17 or M17 or NGC 6618) is in the constellation Sagittarius the Archer. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is by some of the richest star fields of the Milky Way, figuring in the northern two-thirds of Sagittarius. The Omega Nebula is between 5,000 and 6,000 light-years from Earth and it spans some 15 light-years in diameter.
Star Clusters
Let’s start with a few new Messier objects…
Messier 103 (also known as M103, or NGC 581) is an open cluster where a few hundred, mainly very faint, stars figure in Cassiopeia the Queen. It was discovered in 1781 by Charles Messier's friend and collaborator Pierre Méchain. It is located between 8,000 and 9,500 light-years from the Solar System and ranging over about 15 light years. It holds about 40 certain-member stars, two of which have magnitudes 10.5, and a 10.8 red giant, which is the brightest within the cluster. A bright known foreground object is the star Struve 131, not a member of the cluster. The cluster may have 172 stars if including those down to 50% probability of a gravitational tie. M103 is about 22 million years old.
Messier 67 (also known as M67 or NGC 2682) and sometimes called the King Cobra Cluster or the Golden Eye Cluster is an open cluster in the southern, equatorial half of Cancer the Crab. It was discovered by Johann Gottfried Koehler in 1779. Estimates of its age range between 3.2 and 5 billion years. Distance estimates are likewise varied, but typically are 800–900 parsecs (2,600–2,900 ly).
M67 is not the oldest known open cluster, but there are few Milky Way clusters known to be older, and none of those is closer than M67. It is a paradigm study object in stellar evolution:
· it is well-populated
· has negligible amounts of dust obscuration
· all its stars are at the same distance and age, save for approximately 30 anomalous blue stragglers
M67 is one of the most-studied open clusters, yet estimates of its physical parameters such as age, mass, and number of stars of a given type, vary substantially. Richer et al. estimate its age to be 4 billion years, its mass to be 1080 solar masses (M☉), and number its white dwarfs at 150. Hurley et al. estimate its current mass to be 1,400 M☉ and its initial mass to be approximately 10 times as great.
It has more than 100 stars similar to the Sun, and numerous red giants. The total star count has been estimated at well over 500. The ages and prevalence of Sun-like stars had led some astronomers to theorize it as the possible parent cluster of the Sun. However, computer simulations disagree on whether the outer Solar System would have survived an ejection from M67, and the cluster itself would probably not have survived such an ejection event.
Messier 68 (also known as M68 or NGC 4590) is a globular cluster found in the east south-east of Hydra, away from its precisely equatorial part. It was discovered by Charles Messier in 1780. William Herschel described it as "a beautiful cluster of stars, extremely rich, and so compressed that most of the stars are blended together". His son John noted that it was "all clearly resolved into stars of 12th magnitude, very loose and ragged at the borders".
M68 is centered about 33,600 light-years away from Earth. It is orbiting our galaxy's galactic bulge with a great eccentricity of 0.5. This takes it to 100,000 light years from the center. It is one of the most metal-poor globular clusters, which means it has a paucity of elements other than hydrogen and helium. The cluster may be undergoing core-collapse, and it displays signs of being in rotation. The cluster may have been acquired in its gravitational tie to the Milky Way through accretion from a satellite galaxy.
NGC 5466 is a class XII globular cluster in the constellation Boötes the Herdsman. Located 51,800 light years from Earth and 52,800 light years from the Galactic Center, it was discovered by William Herschel on May 17, 1784. This globular cluster is unusual insofar as it contains a certain blue horizontal branch of stars, as well as being unusually metal poor like ordinary globular clusters. It is thought to be the source of a stellar stream discovered in 2006, called the 45 Degree Tidal Stream. This star stream is an approximately 1.4° wide star lane extending from Boötes to Ursa Major.
Solar System Objects
The Moon was almost full when I went out stargazing. It was quite bright and washed out some of the objects I wanted to see that were near it.
The Moon is Earth's only natural satellite. At about one-quarter the diameter of Earth (comparable to the width of Australia), it is the largest natural satellite in the Solar System relative to the size of its planet, the fifth largest satellite in the Solar System overall, and is larger than any known dwarf planet; eg, Pluto.
Stars
I always like to include some stars in each blog entry. Sometimes the info about them can be quite interesting. (All of these stars are blue white. I will try to get more color variety next time.)
Regulus is the brightest object in the constellation Leo the Lion and one of the brightest stars in the night sky. Regulus appears singular, but is actually a quadruple star system composed of four stars that are organized into two pairs. The spectroscopic binary Regulus A consists of a blue-white main-sequence star and its companion, which has not yet been directly observed, but is probably a white dwarf. The system lies approximately 79 light years from the Sun.
Regulus, along with five slightly dimmer stars (Zeta Leonis, Mu Leonis, Gamma Leonis, Epsilon Leonis, and Eta Leonis) have collectively been called 'the Sickle', which is an asterism that marks the head of Leo. The traditional name Rēgulus is Latin for 'prince' or 'little king'. The Regulus system as a whole is the twenty-first brightest star in the night sky with an apparent magnitude of +1.35.
Alkaid /ælˈkeɪd/, also called Eta Ursae Majoris is a star in the constellation of Ursa Major the Great Bear. It is the most eastern (leftmost) star in the Big Dipper (or Plough) asterism. However, unlike most stars of the Big Dipper, it is not a member of the Ursa Major moving group. With an apparent visual magnitude of +1.86, it is the third-brightest star in the constellation and one of the brightest stars in the night sky. Alkaid is a relatively nearby and bright star and has been examined closely, but no exoplanets or companion stars have been discovered. It is 104 light years from the Earth.
Alkaid derives from the Arabic phrase meaning "The leader of the daughters of the bier". The daughters of the bier, i.e. the mourning maidens, are the three stars of the handle of the Big Dipper, Alkaid, Mizar, and Alioth; while the four stars of the bowl, Megrez, Phecda, Merak, and Dubhe, are the bier.
Merak, also called Beta Ursae Majoris is a star in the northern constellation of Ursa Major. The apparent visual magnitude of this star is +2.37, which means it is readily visible to the naked eye. It is more familiar to northern hemisphere observers as one of the "pointer stars" in the Big Dipper, or the Plough (UK), which is a prominent asterism of seven stars that forms part of the larger constellation. Extending an imaginary straight line from this star through the nearby Dubhe extends to Polaris, the north star.
Based upon parallax measurements, Merak is located at a distance of 79.7 light-years (24.4 parsecs) from the Sun. It is a subgiant, a star that has exhausted the hydrogen in its core and is now cooling as it generates energy through the thermonuclear fusion of hydrogen in a shell outside the core. Merak is one of five stars in the Big Dipper that form a part of a loose open cluster called the Ursa Major moving group, sharing the same region of space and not just the same patch of sky from Earth's perspective.
Phecda, also called Gamma Ursae Majoris is a star in the constellation of Ursa Major. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. Based upon parallax measurements with the Hipparcos astrometry satellite, it is located at distance of around 83.2 light-years (25.5 parsecs) from the Sun. It bore the traditional names Phecda or Phad, derived from the Arabic phrase فخذ الدب fakhth al-dubb ('thigh of the bear').
It is more familiar to most observers in the northern hemisphere as the lower-left star forming the bowl of the Big Dipper, together with Dubhe, upper-right, Merak, lower-right and Megrez, upper-left. Along with four other stars in this well-known asterism, Phecda forms a loose association of stars known as the Ursa Major moving group. Like the other stars in the group, it is a main sequence star, as the Sun is, although somewhat hotter, brighter and larger.
Iota Ursae Majoris, also named Talitha, is a star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of 3.14, making it visible to the naked eye and placing it among the brighter members of this constellation. Based upon parallax measurements, it is located at a distance of 47.3 light-years (14.5 parsecs) from the Sun. The traditional name Talitha, comes from the Arabic phrase Al Fiḳrah al Thalitha which means "the third spring, or leap, of the ghazal". Talitha is composed of two sets of binary stars. The two binary systems orbit around each other once every 2,084 years.
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