Monday's latest discovery | Tuesday Shepherd Column
Space Exploration | wednesday Thursday Observation Guide
Friday Deep Space Exploration | Saturday Starry Sky Poem | Sunday and Astronomical Weekly Calendar
Author: Shen Huanyu
Arrangement: Feng Zhong
Some famous Messier objects
M1: Also known as Crab Nebula, the first object of messier's catalogue, the remains of the famous 1054 supernova. What looks like an irregular gray patch in an amateur telescope will reveal a delicate reddish-brown nebula after a long exposure
M4: A large globular cluster located near Scorpio' Heart Ii, with a loose structure and a wide dispersion area. In the clear rural night sky, you can take a closer look with just one binoculars. However, in urban areas with severe light pollution, even large-caliber equipment is difficult to find
M6 and M7: Two open clusters located on the "tail needle" in the constellation Scorpio. M6 is also known as the Butterfly Cluster, and M7 is also known as the Ptolemy Cluster because it was discovered by the Ptolemaic eye. Even in urban areas, they can be viewed with binoculars
M8: Also known as the Lagoon Nebula, it is a launch nebula in the constellation Sagittarius that appears to be the size of five full moons in the night sky. The center of the nebula is also associated with an open star cluster (see Figure 3).
Figure 3, three Messier objects immersed in the stars of the Milky Way. The large emission nebula on the left is M8, and the slightly smaller nebula on the right is red and blue, which is the tri-lobed nebula M20 in the constellation of Centaurus. The small group above M20 is the open cluster M21
M11: Also known as the Wild Duck Cluster, M11 is a very dense open cluster in the constellation of Shields , with up to 3,000 members. In a small telescope, it doesn't look like a wild duck at all, but rather like a loose globular cluster
M13: The Large Globular Cluster in the constellation of Wuxian, one of the largest globular clusters in the Northern Celestial Night Sky. It is said to be visible to the naked eye in extremely sunny situations. When the Arecibo telescope in the United States was built in 1974, it sent a set of high-power radio signals to this globular cluster, which contained human DNA and other information, known as "Arecibo information"
M16 and M17: Similar in position, they are classified in different constellations. M16 is located in the snake head part of the constellation of Serpent, also known as the Eagle Nebula. Hubble's "Pillar of Creation" is located inside M16. M17 is in sagittarius, also known as the Swan or Omega Nebula. In a small telescope, it does look a lot like a swan moored among the stars, with a curved neck and retracted wings
M22: Located in the constellation sagittarius, it is the largest globular cluster visible in the northern sky, and it is also one of the closest globular clusters to Earth, which is slightly better than M13 in brightness, but it is south of the declination and the horizon height is very low, so it is less well-known than the former
M27: Also known as dumbbell Nebula, it is a planetary nebula in the constellation Fox. The visual effect in the telescope is like a gray-white apple core, which after a long exposure of the digital camera will appear as a small dreamy blue nebula
M31: The famous Andromeda Galaxy, at first glance, looks like a candle-like patch in the night sky, even on the outskirts of the city. Located 2.54 million light-years away, the Andromeda Galaxy, with a total mass of more than 150 billion suns, is the first extragalactic object confirmed by astronomers. Its companion galaxies include M32, M110, NGC185, NGC147, and dozens of galaxies of varying sizes. Astronomers calculate that the Andromeda galaxy will collide with the Milky Way in 4 billion years
M33: The famous Triangulum Galaxy, with its low surface brightness, is visible to the naked eye in the extremely clear night sky. It is the third largest galaxy in the group after the Andromeda Galaxy and the Milky Way
M44: The famous Ghost Cluster, also known as the Beehive Cluster, is an open cluster visible to the naked eye in the constellation Cancer. In ancient China, it was called "corpse gas" and believed that it was composed of the ghost fire of the ascension to heaven
Figure 4, the open cluster M46 and the planetary nebula hidden within it, were first discovered by the British astronomer William Herschel in 1786
M46 and M47: Two contrasting open clusters in the constellation of Stern, the former with a large and fine number of members and a striking visual effect under the clear night sky, and the latter's bright and sparse member stars, which can also be viewed with binoculars in urban areas. Interestingly, an elaborate planetary nebula, NGC 2438, is hidden on the northern edge of M46, which is easily mistaken for the remains of a dead star in M46. However, in-depth research has shown that it is not a member of M46, but that the two lines of sight coincide (see Figure 4).
M51: The Whirlpool Galaxy in the constellation of Hound, the first galaxy in astronomical history to be found to have a spiral arm. M51 has a companion galaxy nearby, NGC 5195, which interacts with it. It was also the first pair of interacting galaxies discovered by humans
M57: The beautiful Ring Nebula, located between the γ Lyra and the β, is a planetary nebula. M57 has a high surface brightness and the viewing effect is less affected by light pollution, but due to its narrow viewing area, it is more suitable for viewing under astronomical telescopes. At first glance, the M57 looks like a delicate gray-white smoke ring, which can be distinguished by the camera's long exposure of its shell structure: the inner layer is blue-green, and the outer layer is reddish. The former comes from the OIII transmission line, while the latter comes from the Hα and NII lines. It is worth mentioning that the blue-green OIII emission line is the main feature of many planetary nebulae. According to the atomic jump law of quantum mechanics, the OIII line is a Forbidden Line, and such an emission line would never appear in a ground-based laboratory. However, it may exist in the extremely thin space of the universe
M65 vs M66: This is a pair of galaxies located in the lower part of the constellation Leo. In fact, there is another lateral galaxy near these two galaxies, NGC 3628, which together form the Leo Triplet. This is also one of the most frequently observed targets by astronomy enthusiasts
M81 vs M82: These are a pair of interacting galaxies in the constellation Ursa Major that can be located even on the outskirts of towns with slight light pollution. M81, also known as Bode's Galaxy, is a massive spiral galaxy. M82, nicknamed Cigar Galaxy, is a Starburst Galaxies near the former. In fact, a medium-aperture telescope alone allows you to see the penetrating crack in the center of M82. The Spitzer Space Telescope revealed that the galaxy's core was undergoing an incredible wave of star births, with a large number of newborn stars violently heating up the dust belts in the nucleus, causing them to emit infrared rays equivalent to 30 billion times the luminosity of the sun. What exactly caused such an amazing starburst process? This is an astronomical mystery
M87: This is an elliptical galaxy in the constellation Virgo, also known as the Virgo A galaxy, which is almost the largest elliptical galaxy known to people. The M87 core is bright and unrecognizable. Hubble once observed a huge jet at its core, erupting outward at high speed. Early analysis suggested that the M87's core jet was faster than the speed of light, only to find out that it was nothing more than a visual "pseudo-faster-than-light speed."
Figure 5 shows M97 and M108, located near the Big Dipper, about 48 arcminutes apart, slightly wider than the width of a full moon. In reality, however, M97 is an object within the Milky Way, and M108 is an extra-Milky Way galaxy
M97: See Figure 5, also known as the Owl Nebula, a planetary nebula in the constellation Ursa Major. The surface of the M97 is covered with OIII blue-green launch lines, and it does look a lot like the face of an owl. Next to M97 is the messier planet Number 108, a lateral barred spiral galaxy. Such a rare combination of deep-sky objects will always attract the coveted attention of many celestial photographers
M101: Nicknamed Pinwheel Galaxy, it is a spiral galaxy located at the edge of the northern constellation Ursa Major, almost entirely facing Earth, occupying an area the size of a full moon. If the weather is clear and light-free, it can be viewed with binoculars
Figure 6, M104 in the visible light band taken by Hubble
M104: See Figure 6, the famous Sombrero Galaxy, in the constellation Virgo. The Hubble image once made the object famous. M101 is a set of contrasting targets, the former being a typical galaxy-oriented and the latter being a typical lateral galaxy. When galaxies face us in different postures, they can often show very different characteristics. Taking the M104 as an example, we can clearly see the thick dust bands on its disk surface. In fact, our milky way has a similar dust belt that splits the huge milky way in the night sky in two. Such an analogy suggests that perhaps our side view of the Milky Way will be very similar to the M104 above
Pastoral New Media Editorial Department
"Astronomical Wet Engraving" produced by Shepherd
WeChat: astronomycn
Messier's periodic table
via Shepherd Astronomy
◢ Appreciate the author of this article ◣
Remember kamufu jun's friend after the reward: aimufu
Thanks for reading