In the seemingly vast vault of heaven, the constellation Sagittarius is the third smallest constellation. It is located in the Northern Hemisphere of the sky and occupies only 80 square degrees of its area.
In terms of area, the Sagittarius constellation ranks 86th in the ranking of the existing 88 constellations. In a given limited area we can see about twenty visible stars. Only two stars out of these two dozen are lucky enough to have a fourth magnitude.
The Sagittarius constellation is one of the few objects in the drawing of which you can see a direct display of the name. Indeed, by connecting the brightest stars of the constellation with conventional lines, you can easily imagine a flying arrow. The constellations adjacent to Arrow are Dolphin and Chanterelle, Hercules and Eagle. Since the constellation is located in our hemisphere, we can easily see it on the territory of our country. However, in order to fully enjoy the constellation and study its features, it is worth starting observations in July.
Let's walk on the bright stars
Star Gamma
At the very tip of the Arrow is the star Gamma, which has the highest magnitude in this constellation. The apparent magnitude of this M class star is 3.51m. This red giant is 640 times more luminous than the Sun. Gamma Arrow is located 275 light years from our planet.
Delta Arrow
Delta Sagittarius is a paired system and the second most violent star in the constellation. Two luminaries found their place in its composition: a powerful class M giant and a more modest class A dwarf. This binary system has a total apparent brightness of the fourth magnitude. The distance to Earth from this object is almost 450 sv. years.
The only star in Arrow that has its own original name is Alpha or Sham. The star is considered a bright yellow giant located at 475 sv. years from our house. The spectral class of the Sham star is defined as G0II, and its apparent magnitude is 4.39m. Alpha Sagittarius is four times more massive than the Sun and approximately 340 times brighter in luminosity.
Messier Objects and the Sagittarius constellation
NGC 6838
There are a couple of notable Messier objects in the constellation in question. The first of them appears to be a cluster named M71, otherwise NGC 6838. Back in 1745, this cluster was discovered by J. Chezot, however, it was included in the astronomical catalogs of Charles Messier only in 1780. The M71 cluster is located between the stars Gamma Arrow and Delta, located 18 thousand light years away. years from our planet. The cluster's diameter extends to 27 light-years. years old and has an apparent magnitude of 8. For a long time there has been scientific debate about the type of cluster - whether it is open or globular. However, today NGC 6838 is still classified as a weakly concentrated globular cluster.
NGC 6839
A less noticeable Messier object in Sagittarius is supposed to be the compact cluster NGC 6839. It has only an 11th magnitude. The cluster was discovered in 1784 by William Herschel.
How did the constellation Arrow appear in the sky?
The ancient constellation Sagittarius was introduced in the second century by Ptolemy. Since the shape of the constellation resembles an arrow, in a number of ancient cultures it was identified with a type of weapon, for example, among the Greeks, Persians, and Romans. Greek myths associate the constellation with the arrow of the god of love Eros, with the arrow of Hercules, with which he killed the eagle that pecked the liver of Prometheus, and also with the arrow of Apollo, with which he exterminated the Cyclopes.
| List of constellations of the autumn sky | |
|---|---|
| · · · · | |
> Arrow
| An object | Designation | Meaning of the name | Object type | Magnitude |
| 1 | M71 | No | Globular cluster | 8.20 |
| 2 | Gamma Arrows | No | Red giant | 3.47 |
| 3 | Delta Arrow | No | Multiple star system | 3.68 |
| 4 | Sham (Alpha Arrow) | "Arrow" | Yellow giant | 4.39 |
| 5 | Beta Arrows | No | Yellow giant | 4.39 |
Coordinates constellation Sagittarius in the northern hemisphere: position on the star map, facts with photos, myth and legend, bright stars, nebulae, clusters, asterism.
Arrow - constellation, which is located in the northern sky, and from Latin “Sagitta” is translated as “arrow”.
Belongs to the Greek constellations recorded in the second century by Ptolemy. Represents the arrow of Hercules in myths.
Ranks third among tiny constellations. The Sagittarius constellation does not have stars greater than 4th magnitude and is not rich in interesting objects.
Facts, position and map of the Sagittarius constellation
| Arrow | |
|---|---|
| Lat. Name | Sagitta |
| Reduction | Sge |
| Symbol | Arrow |
| Right ascension | from 18 h 52 m to 20 h 15 m |
| Declension | from +15° 45’ to +21° 15’ |
| Square | 80 sq. degrees (86th place) |
| Brightest stars (value< 3 m ) |
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| Meteor showers | |
| Neighboring constellations |
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| The constellation is visible at latitudes from +90° to -68°. The best time for observation is July. |
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There are no noticeable stars with brightness greater than magnitude 3.00, and only one is closer than 32.6 light years (10 parsecs). The brightest is Gamma Arrow, whose apparent magnitude reaches 3.51. The closest is Gliese 745 (M1.0VI) with a distance of 28.14 light years. Consider the diagram of the constellation Sagittarius on a star chart.
There are three stars with planets and one Messier object. No meteor showers were detected. Part of the Hercules group, where , , and are also located.
The myth of the constellation Arrow
In most myths, the constellation depicts the arrow of Hercules, with which he killed the eagle sent by Zeus to punish Prometheus. This hero created people from clay in the image of the gods and gave them fire, which he stole from Olympus. Zeus got angry and chained him in the Caucasus. The eagle took forever to peck at the liver (it grew back at night). Hercules found Prometheus on one of his campaigns and shot an arrow at the eagle.
This could also be Apollo's arrow, with which he destroyed the Cyclops. It was these creatures who created lightning for Zeus, who killed Asclepius (son of Apollo). Or it belongs to Eros (Cupid), who made Zeus fall in love with Ganymede (the shepherd - Aquarius). In this story, the Eagle guards the arrow in the sky. The Greeks called the constellation "Oistos", and the Romans changed it to "Sagitta"
The main stars of the constellation Sagittarius
Explore the bright stars of the Arrow constellation of the northern hemisphere with detailed descriptions and characteristics.
Gamma Arrows– an orange giant (K5III) with an apparent visual magnitude of 3.51 (leading in brightness in the constellation) and a distance of 274 light years. 640 times brighter than the Sun and 2.5 times greater in mass.
Delta Arrow– star system (M2II + B6) with an apparent visual magnitude of 3.68 (2800 times brighter than the Sun) and a distance of 448 light years. It is represented by a bright red giant and a blue-white main sequence star with an orbital period of 3725 days.
Alpha Arrows– a yellow giant (G1 II) with an apparent magnitude of 4.39 (the third brightest in the constellation) and a distance of 620 light years. It is 4 times larger than the Sun in mass, 20 times larger in radius and 340 times brighter.
The traditional name Sham (Alsham) comes from the Arabic sahm - “arrow”.
Beta Arrows– a yellow giant (G8IIIa) with an apparent visual magnitude of 4.387 and a distance of 470 light years. The radius is 10 times larger than the sun.
Zeta Arrows is a triple star system located 326 light years away. The apparent visual magnitude is 5.01. The main object is a white main sequence star (A3V).
This Arrows– an orange giant (K2III) with an apparent magnitude of 5.09 and a distance of 162 light years.
Epsilon Arrows- a multiple star system with an apparent magnitude of 5.67 and a distance of 473 light years. The main object is a yellow giant (G8IIIvar).
15 Arrows is a yellow main sequence star (G0V), whose visual magnitude is 5.8. Located 57.7 light years away. This is the solar analogue.
In 2002, a brown dwarf (L4) was found in a long-period orbit. It was the first candidate for brown dwarf status orbiting a solar counterpart. Found while viewing archived images.
HD 231701– a yellow-white dwarf (F8V) with a visual magnitude of 8.97 and a distance of 353.6 light years. In 2007, a planet similar to Jupiter was discovered with an orbital period of 142 days.
Theta Arrow- a multiple star system with an apparent visual magnitude of 6.51 and a distance of 147 light years. The main star is a yellow-white subgiant (F5IV). Age – 1.9 billion years.
S Arrows– a Cepheid variable (F8-G7), whose brightness fluctuates from 5.5 to 6.2 over 8.38 days. It is located 4289 light years from us, and its average apparent magnitude reaches 5.71.
U Arrows– eclipsing variable of Algol type (B8III+K). The apparent visual magnitude is 6.50, and the distance from us is 1.012 light years.
9 Arrows(QZ Sagittarius) is a blue supergiant (O8e) with an apparent magnitude of 6.24 and an absolute magnitude of -6.95. It is located 14,174 light years from the Sun and is part of a multi-star system.
Celestial objects about the constellation Sagittarius
Messier 71(M71, NGC 6838) is a weakly concentrated globular cluster. The apparent visual magnitude is 6.1, and the distance is 13,000 light years. It is 27 light years wide and has a brightness of 13.2 thousand suns.
In 1746 it was found by Jeanne Philippe de Chézeau, and in 1780 it was included in the catalog of Charles Messier.
Necklace Nebula(PN G054.2-03.4) is a planetary nebula 15,000 light-years distant from our system. Found in 2005. It formed after a giant star came too close to a binary companion and exploded.
NGC 6839 is not a deep sky object, but an asterism that was added to the New General Catalog of Nebulae and Star Clusters (NGC). Its apparent visual magnitude is 8.4.
On August 18, 1784, he was found by William Herschel. Sometimes called a cluster. Contains 11 stars with magnitude 11 and fainter.
M1-67 is a nebula created by extruded material from the Wolf-Rayet star WR 124. It is 6 light-years wide and has an expansion rate of more than 150,000 km/h.
It is one of the fastest escape nebulae in the Milky Way, with a radial speed of 200 km/s. The star was discovered in 1938 by American astronomer Paul W. Merrill. This is an eruptive variable with a range of 0.08 magnitude.
Age – 8.6 million years. The initial mass was 25 solar masses, but now it is 9 solar masses because it blew away most of the material. WR 124 is 10,900 light-years away and 150,000 times brighter than the Sun. The average apparent value is 11.50.
– a planetary nebula with a visual magnitude of 11 and a distance of 8000 light years. The expansion speed is 20 km/s. It is believed that this is a very young nebula and its age does not exceed 700 years.
NGC 6886– a planetary nebula with an apparent magnitude of 11.8 and a distance of 4900-17900 light years. On September 17, 1884, it was discovered by the English astronomer Ralph Copeland.
Modern astronomy, unlike ancient astronomy, understands a constellation not as a group of stars forming some memorable figure, but as a certain area of the sky on the imaginary surface of the celestial sphere. Such an area includes not only stars, but also all other objects located within its boundaries.
In the first third of the 20th century, the International Astronomical Union finally approved the boundaries of 88 areas - constellations into which the entire earth's sky was divided. They differ very significantly in the area they occupy on the celestial sphere - from the tiny Southern Cross to the giant Virgo, Hydra and Ursa Major. One of the smallest areas in the sky is occupied by the constellation Sagittarius. The Latin, that is, international, name of the constellation is Sagitta (abbreviated Sge). Despite its modest size, it has been known since ancient times.
History and legends
A group of stars forming a characteristic arrow-shaped constellation configuration was familiar in ancient times to the inhabitants of the Middle East, Greece, and Rome. Claudius Ptolemy in the 2nd century included the Arrow in his astronomical catalogue, which, after translation from Arabic, became known in medieval Europe as the Almagest.
There are several mythological versions that explain the presence in the sky of an object so recognizable to the ancients. According to one of the most common legends about the constellation Arrow, Hercules (Hercules) shot it at the eagle Zeus, who was pecking at the liver of the titan Prometheus chained to a rock. Judging by the relative position of the indicated constellations, the formidable weapon flew past the target...
Another myth, transmitted by Eratosthenes, claims that the Arrow was sent by Apollo in revenge for his son Asclepius to the Cyclops. After all, it was these giants who forged lightning for Zeus, with which he struck the god who gave people hope for immortality.
However, people did not always see this combination of stars as an arrow. Such Latin names of the constellation have reached us as Dart, Reed Stick (for writing), Pillar and some others.
Sky position and observation
The arrow is located in the northern hemisphere of the celestial sphere, covering an area of only about 80 square degrees (smaller areas of the sky are occupied only by the Lesser Horse and the Southern Cross). Neighboring it are the small constellations Chanterelle and Dolphin, the rather large and clearly visible and huge Hercules.
The arrow can be seen from almost the entire surface of our planet, with the exception of the Antarctic region south of -74° latitude. North of -68° it is characterized by full visibility. In the middle latitudes of the northern hemisphere, the constellation can be observed from late spring to mid-autumn, and the best time for observations is in July-August.
The easiest way to find the Arrow in the sky is to rely on the location of the so-called Great Summer Triangle (Vega, Deneb, Altair), as soon as the stars become visible after sunset. Below the constellation Sagittarius is the lower apex of the Triangle - Altair, and Vega and Deneb lie on imaginary lines close to the ends of the Sagittarius.
About two dozen stars can be distinguished with the naked eye, four of which, forming an arrow-shaped figure, are brighter than 5m. However, just looking through binoculars makes it possible to see a whole scattering of stars, since the strip of the Milky Way passes through the constellation Sagittarius. The photo below was taken using a standard digital camera.
This small area of the sky is not rich in spectacular objects, but an astronomy lover, armed with a small telescope or even simple binoculars, will still find something interesting there.
Brightest stars
The brightest star here is the red giant Gamma Sagittarii, which forms its “tip”, with a magnitude of 3.51 m. Gamma is located at a distance of 260-275 light years from the Solar System, its luminosity apparently exceeds the solar one by approximately 640 times. The surface temperature of this star does not exceed 4000 Kelvin, its mass is 2.5 times greater than the mass of the Sun, and in size this giant star is 55 times larger than our star.
Delta Sagittarii, about 4 m in magnitude, also having a reddish tint when viewed through binoculars, is a binary system of a red giant and a blue-white giant. However, these components are not visible to visual observation. They can only be resolved through spectroscopic methods.
Alpha Arrow, which has its own name Sham, or Alsham, is a yellow giant of magnitude 4.4 m. In the constellation Sagittarius, Sham forms the upper part of the “plumage”. It is 4 times more massive than the Sun, 20 times larger, shines 340 times more powerfully and is located at a distance of 470-475 light years.
Beta Sagittarii, respectively the lower half of the “plumage”, is a star that is generally quite similar in physical parameters to Sham, but it is somewhat more massive and cooler.
The Sagittarius constellation includes a number of variable stars, among which there are some that are accessible to observation using amateur equipment.
Thus, a very popular object is the eclipsing variable U Sagittis, located to the right of the main figure of four bright stars. This is a binary system, the distance between the components of which is so small that one of them eclipses the other every 81 hours 8 minutes, that is, 3.4 days. The plane of the eclipsing companion's orbit practically coincides with the line of sight, so that the observer sees total eclipses accompanied by a rapid decrease in brightness by 2.5 magnitudes. The duration of the eclipse is 1 hour 40 minutes.
In addition, the classical Cepheid S Strela with a period of 8.38 days is of considerable interest. During this time, the brightness of the pulsating supergiant star changes from 5.2 m to 6 m.
Unusual cluster and planetary nebulae
In addition to variables that are attractive to the observer, as well as multiple stars, the constellation Sagittarius includes the globular cluster M71 with a magnitude of 8.3 m. It is located 13,000 light years away and has a diameter of 27 light years. This is such a rarefied object that for a long time astronomers could not decide on its classification, mistaking it for an unusually dense open cluster rich in stars. However, it is now generally accepted that M71 is spherical, albeit weakly concentrated.
Owners of amateur telescopes can also enjoy the constellation with two small planetary nebulae of a blue hue - NGC 6879 and NGC 6886. However, observing them is very difficult due to their low brightness (13 m and 12 m) and the small angular sizes of these stellar remnants.
Cosmic call
Two of the stars in the Sagittarius constellation, unremarkable at first glance, have an important feature: they are similar to the Sun in spectral class and are located at a fairly close distance from it. Therefore, the stars 15 Arrows and HD 178428, distant from us by 58 and 68 light years, respectively, were chosen along with two other similar luminaries as recipients of the interstellar radio message of earthlings Cosmic Call (“Cosmic Call”).
An appeal to possible extraterrestrial civilizations was undertaken on the initiative of A.L. Zaitsev, a specialist in space radar and an enthusiast of the search for intelligence in the Universe. It took place in 1999; the Evpatoria radio telescope RT-70 was used to send it. In 2003, “Cosmic Call” was sent a second time, to other stars.
The message contains a condensed list of human knowledge in various fields of science, as well as brief addresses and wishes from many people from different countries. It will reach Star 15 Arrow in 2057, and HD 178428 in 2067.
Discreet Charm
Of course, little Arrow is not a constellation that can immediately attract attention, like the bright, spectacular and rich in various spectacular objects Cygnus or Pegasus. However, the Universe is inexhaustible in almost any direction, and a true amateur astronomer will not miss this small piece of sky, finding interesting and exciting cosmic phenomena there too.
(Latin Sagitta, Sge) - constellation of the northern hemisphere of the sky. It occupies an area of 79.9 square degrees in the sky and contains 28 stars visible to the naked eye. Alpha Sagittarius (α Sge) is a double star.
It is observed in Ukraine and throughout Russia. The best conditions for observation are in July.
Connected mentally by lines, the brightest stars of the Sagittarius constellation form a figure in which, without much effort of imagination, you can see a flying arrow.
There are no interesting objects in this constellation that can be observed with the naked eye or with a conventional telescope.
- 15 Arrows - sun-like star, to which in 1999 it was sent radio message from the inhabitants of the Earth to extraterrestrial civilizations.
- WZ Arrows - dwarf nova type SU, changing brightness from the usual 15m to 7m during flares, the last of which were in 1913, 1946, 1978 and 2001.
- S Arrows - long-period Cepheid. Its brightness varies from 5m.8 to 7m over a period of 8.38 days.
Story
Ancient constellation. It was known by the same name to the Greeks, Romans, and the Middle East since ancient times. Included in the starry sky catalogue.
There are many myths that explain the appearance of the constellation in the firmament and connect it with neighboring constellations, but they are all secondary.
click on the image to enlarge it
Constellation Sagittarius from the Atlas "Uranographia" by John Hevelius (1690)
Constellation Sagittarius from the Atlas "Uranographia" by J. E. Bode (Berlin 1801)
click on the image to enlarge it
Constellation Sagittarius from the Atlas "Urania's Mirror" (London, 1825)
Mythology
Mythology tells the following about the appearance of the constellation Arrow in the sky.
With this arrow, Hercules killed the eagle vulture that was tormenting the chained Prometheus (see the eleventh labor).
Or, if you believe the version that and - these are the Stymphalian birds of the third labor - the Arrow struck these birds.
On the other hand, Eratosthenes believed that this was an arrow used by Apollo to take revenge on the one-eyed giants Cyclopes, who gave Zeus lightning, with which he killed Asclepius, the son of Apollo. It is known that Apollo killed the Cyclops, but it is usually believed that simply because of a burning resentment over the death of his son, he took revenge on the offender Zeus, for whom the giants performed all sorts of handicraft work. It was after this that Hephaestus took the place of the full-time blacksmith.
Eratosthenes refers to Heraclides of Pontus and says that this arrow was of enormous size. This probably explains that only one arrow was enough to beat the Cyclops: Apollo hit them, swinging the arrow like a club :)
Going out on a dark August night and looking into the very middle of the Summer-Autumn triangle formed by the bright stars Vega, Deneb and Altair, you can see Arrow flying across the sky without making a single sound - a small constellation surrounded on all sides by a silvery glow Milky Way. Who launched this Arrow? Most likely, this is Sagittarius - after all, it was this celestial character that was always depicted on ancient star maps with a bow in his hands.
I would like to ask another interesting question when looking at this heavenly Arrow - who will it hit? Flying east, she is clearly not afraid of either the Swan, the Eagle, or the Chanterelle. The more likely target is Pegasus, but, in all likelihood, the Arrow will reach him, hitting the Dolphin that jumped out of the water (naturally, one must imagine that he does not stand still, but moves forward, like the Arrow)! So an archer went out hunting or fishing and shot an arrow into the sky, and maybe it wasn’t an arrow at all, but a harpoon?
Let's begin our acquaintance with the astronomical "pantry" of Strela by comparing the colors of its four brightest stars - α, β, γ and δ. This is best done with binoculars that have a field of view of five degrees or more - then you will be able to take in the whole four at a glance. First, compare the colors α and β of the Arrow. According to my feelings, they are exactly the same (light yellow), however, accurate photometric observations show that β is slightly “redder” than α.
Now turn your attention to the pair γ and δ: isn’t it true, the colors of the stars that make it up are already noticeably shifted to the “red side” compared to the color of the stars from the first pair? Here, again, it should be noted that accurate measurements show that the star γ is slightly more “red” than δ. Will you be able to notice this difference?
Binoculars will also help us in searching for the next object in the constellation - an eclipsing variable star U Arrows, located one and a half degrees west of the “Hanger” asterism (Collinder 399), popular among astronomy enthusiasts, from the constellation Chanterelle. The U Sagittis system consists of two nearby stars, one of which obscures the other every 3 days, 9 hours and 8 minutes, as a result of which the brightness of the variable fluctuates in the range from 6.6 m to 9.2 m. The Earth is located almost exactly in the plane of the orbit of the companion star, and we can observe total eclipses of one component by another, which last 1 hour 40 minutes - all this time the brightness of the variable, which is at its minimum, remains constant (9.2 m). Some observers place U Sagittarius among the best variable stars in the sky, even ahead of the famous Algol, since the declines and rises in brightness of the latter do not occur so quickly and dramatically.
Let us now return to the “original position” - to the pair of stars α and β Sagittarius. 1.5° south and slightly west of the middle of the segment connecting them, on the very border with the constellation Aquila, there is a bright and wide double system ε Arrows. Its 6th and 8th magnitude components are separated by as much as 89", so the "power" of ordinary binoculars is quite enough to separate this binary. However, in order to determine the colors of the binary's components, you will probably need a telescope. It seemed to me that the main star of the system has a yellowish tint, and its satellite is a “diluted” blue. In general, this is not the best system in the sky, and besides, the distance between the components is too large - the feeling that the star is double disappears.
A much more interesting double is located very close - just half a degree to the east. Denoted as Herschel 84, this system consists of a brick-red 7th magnitude primary star and a dark blue 9th magnitude companion 30" to the northwest. The colors of both stars appear especially saturated after the faded hues of ε Sagittarius.
Having "snacked" on doubles and variables, let's now move on to the "main dish" - a globular star cluster Messier 71(M71), undoubtedly the most interesting object in the Sagittarius constellation from the point of view of an amateur astronomer. However, professional astronomers also spent a lot of time studying this cluster. Take the fact that one of the pioneers of astrophotography, Isaac Roberts, who discovered the spiral structure of the Andromeda Nebula at the end of the last century, believed that M71 also has spiral arms that form faint stars located along the periphery of this object! Subsequently, when the galactic nature of this “star heap” was no longer in doubt, disputes flared up on another issue: what is it - an open or globular cluster? Thus, famous astronomers Robert Trumpler and Harlow Shapley believed that M71 is an open cluster, albeit an unusually dense one. However, later studies refuted this assumption.
It is easy to understand the reason for the difficulties in determining the status of M11 by looking at it through a telescope with a sufficiently high magnification (the cluster is located halfway from δ to γ Sagittarius). Even with modest amateur instruments, this object easily, perhaps too easily for a globular cluster, breaks up into individual stars. Indeed, the picture looks more like a star-rich open cluster than a globular cluster. Again, the shape of M71 is not round, like that of other “globular” clusters, but cone-shaped, moreover, it does not have the concentration of stars towards the center that is characteristic of globular clusters. The object is surrounded by a large number of Milky Way stars, forming intricate figures: rhombuses, crosses, ovals... And sometimes it really begins to seem that the chains of these stars are the very “spirals” that misled Roberts.. .
Looking at M71, notice the beautiful "Y''-shaped group of stars located to the west of the cluster (if you want, you can find many similar asterisms in Strela). Just 25" south of it is a very "real" open star cluster Harvard 20(Harvard 20). This object is unlikely to arouse much enthusiasm among owners of binoculars or small telescopes - just think, a few stars, visible, at best, against the background of a barely noticeable strip of light. My 20-cm Newton allowed me to see 2-3 dozen stars here, forming the figure of an acute triangle facing the southeast.
Sadly, this is where the list of Arrow star clusters ends, so we will again return to individual stars, although not quite ordinary ones. One of them, X Arrows, is located 40" north of the star η, which forms the "tip" of the Arrow. This is a semi-regular variable star, varying its brightness in the range of 8.7-9.711, with an average period of 196 days. Searching for this variable is not difficult, since its extremely saturated The red, one might even say burgundy color makes it stand out among its “faceless” neighbors and generally allows it to be ranked among the elite category of the reddest stars in the entire sky.
By moving the telescope tube 1.2° to the northeast, we stumble upon a beautiful triple system θ Arrows. At a distance of 11" there is a bright light yellow star of 6th magnitude and a noticeably contrasting greenish satellite of 9th magnitude. A little further, at a distance of 89" is the third member of the "team", a yellow star of 7th magnitude.
There are also two planetary nebulae in the Sagittarius constellation that are accessible for observation with amateur telescopes. In Dreyer's New General Catalog (NCG) they are designated as NGC 6886 And NGC 6879. The first of them is located approximately a degree from 0 Arrow, the second is another three degrees to the south. Unfortunately, both objects have low brightness (12.2 m and 13.0 m). Their angular sizes are also small - 5.5" and 5" respectively, which is why even at high magnifications the nebulae remain star-like (only with an exceptionally calm atmosphere do they look like "defocused" stars when observed with high magnification). We hope that the following fragments of the Palomar survey with stars up to 20th magnitude will help you succeed in your search for these planetary nebulae. And remember that the “distinctive” feature of these two objects is their deep blue color.
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