On these dates it is very likely that many of you who read us will enjoy your holidays shortly if you are not already enjoying them. If so, it is possible that your destination has starry skies (the crisis has caused many municipalities to turn off part of the public lighting that was excessive and we have noticed a small decrease in light pollution).
Before you close your suitcase, we recommend that you put some simple binoculars inside and add to the list of destinations to visit the following deep-sky objects that we recommend for the next few nights of relaxation. We hope you like them:
5 deep sky objects this summer
M27 : This planetary nebula, known as the Dumbbell Nebula, is located in the constellation Vulpecula (or zorrilla) about 1,250 light years from us. It is easy to find with binoculars 3 degrees north of the gamma star Sagitae on the Arrow (Sagita) as a small irregular grayish star. Of course, we will observe it much better with a telescope where it will appear in the shape of a whitish “plate”. The great challenge of planetary nebulae is to find the small white dwarf star inside, but for this we will need large aperture telescopes. Do not worry about it, the simple view of the remains of the explosion of that star through your binoculars will be worth it.
M27. Dumbbell nebula
M13 : The Hercules Cluster is one of the most spectacular globular clusters that we can observe. It is about 25,000 light years from us. Much further than the M27 nebula right? But do not distrust, through your binoculars it will be even more spectacular than the previous one. You will appreciate a very striking grayish circular “spot”, as if it were a faint star but much wider than normal. It is easy to locate M13 in the constellation of Hercules, halfway between the stars Vega (Lira) and Arturo (Boyero).
M13. Hercules Cluster.
– M57 : It would be unfair to talk about M27 and forget about another beautiful planetary nebula. In this case that of the Lyra. It is smaller than the previous one, but also in a more defined and contrasting way. It appears as a small disk (which is why it is also known as the Ring Nebula) in our telescopes and is easily mistaken for a star through binoculars. It is located 2,300 light years from us, in the constellation that gives it its name, the Lyra. We will find this object between the stars Beta and Gamma Lyrae.
M57. Ring nebula
Location map (click to enlarge)
M6 : We are now heading south, and to the summer constellations of Scorpio and Sagittarius. Our first stop is the Butterfly Cluster. It is a beautiful open cluster located in the constellation of Scorpio 1,600 light years from us. It is shown to us as a set of very fine stars that suggest the appearance of a butterfly with open wings. As this object is relatively close to the galactic center, we will obtain during its search a field full of stars that will undoubtedly pose the search in a very attractive challenge. Appreciating the slight haze that surrounds the stars of the cluster will be a challenge for the most expert eyes.
M6. Butterfly Cluster.
M8 : The Lagoon Nebula is almost as spectacular in the summer skies as the Orion Nebula is in the winters. Located in the constellation of Sagittarius about 5000 light years from us, this emission nebula appears with a characteristic reddish hue in the photographs but visually and with our binoculars we can only distinguish a grayish haze of irregular shape. However, its observation always implies a great emotion for the novice observer and it is one of the objects most photographed by astronomers during these dates.
M8. Lagoon Nebula.
Location map (click to enlarge)
M31: And we save the main course for last. Of course, we will have to wait until dawn to observe this majestic galaxy, the Andromeda Galaxy. It is 2.5 million light years from us. Of all the objects that we have talked about, it is by far the most distant (however we are talking about a celestial object that is outside our galaxy, it is another galaxy different from our Milky Way). Despite its size and brightness is such that we can even appreciate it without the need for binoculars. It is worth spending a few minutes observing this object and letting our eyes adjust to appreciate little by little more and more details of this galaxy. His view from very dark skies is truly spectacular. To find it, we must turn our gaze to the north. There, in the constellation Andromeda that gives it its name,
M31. Andromeda Galaxy.
Location map (click to enlarge)
We hope you enjoy your holidays and see you all here again when you return. If you have not yet decided your destination, stop by Turismo Estelar and there you will find a wide range of hotels and rural houses located in areas with the best skies in Spain .
And if you don’t have binoculars or you want to see these objects that we have talked about in our telescopes and from a place with an exceptional sky, we encourage you to sign up for our summer activities to see the Perseids . We will take our telescopes and you will enjoy these and other secrets of the Universe in a hilarious activity. We wait for you!
Deep sky;Facts You Must Know
Here we recommend some non-stellar objects that deserve a little attention from the hobbyist and that do not cease to be sources of satisfaction for the good observer. Patience, good luck and enjoy!
M45 in Taurus
The Pleiades, an open cluster well known to all observers and perfectly recognizable to the naked eye . The “seven sisters” are distinguished, seven stars in visual magnitude that are converted into dozens with 10 x binoculars . It is a young cluster of only a few tens of millions of years in which all its components are blue-white giants that are still within the original nebula in which they formed. Given its proximity to us (about 410 light-years) its angular dimensions are remarkable, about 100 arc minutes . With a telescope the vision is spectacular with hundreds of faint stars in the visual field, being able to distinguish the filaments of the nebula that surrounds them and the fainter and colder “flash stars” or flash stars that present sudden increases of luminosity like T Tau.
M1 in Taurus
The Crab Nebula or NGC1952 is the prominent remnant of a supernova observed and recorded by Chinese astronomers in AD 1054 and which for 23 days was brighter than Venus, being observed even in broad daylight. The cloud of debris produced continues to expand at 1500 km / s, so its appearance has changed significantly since it was first studied with a telescope. It is about 7000 light-years from Earth and is not visible to the naked eye. With 12 x 50 binoculars it is barely distinguishable under extremely favorable conditions, and it is with a telescope that its true morphology is appreciated. Unlike most nebulae, the Crab is brightest in the center due to the presence of a still active energy source at its heart that keeps the nebula warm and fuels its expansion. Only with professional telescopes is it possible to distinguish this source as a very faint star consisting of a pulsar rotating at 30 revolutions per second (pulsar NP0523).
M44 in Cancer
Another remarkable naked-eye open cluster within the faint zodiacal constellation Cancer. Framed between the stars g and h to the north and dyq to the south, it is also known as the Manger . The Roman historian Pliny the Elder calls it that (Praesepe) and describes it together with two of the stars that he calls asellus = “the asses”, gamma Cnc or Asellus Borealis and delta Cnc or Asellus Australis. Its dimensions are remarkable, 80 minutes of arc and a magnitude of 4.5 that make it easily locatable. A large number of young bluish-white stars can be seen with simple binoculars. With a telescope it is convenient not to use large magnifications to appreciate it in all its beauty. The most luminous star is e Cnc with a magnitude of 6.3, but there are about 80 that exceed the 10th. The M44 and M45 are thought to have formed at about the same time.
M42 in Orion
The Great Orion Nebula is one of the best known and most beautiful nebulae in the sky . It is an obligatory observation point for the beginner, as it is easily located with the naked eye within the constellation of Orion. This cloud is associated with a region of star formation and inside it is observed some of the brightest ones wrapped in gas and dust. It is, therefore, an emission nebula in which hot stars illuminate the entire nebula from within.. With binoculars, the Trapezoid is distinguished, a group of four stars inside the nebula responsible for its brightness and barely 1 million years old. As a whole, M42 shows a magnitude of 5 with dimensions of 66 x 60 arc minutes. 8 ‘NE of M42 is another similar nebula. M43 is illuminated by a magnitude 8 star and surrounds the nebular variable UN Ori. With a telescope it is possible to distinguish regions of dust and gas that contrast with the bright nebula as well as its filaments. It represents a good and grateful objective to start and improve in astronomical photography with which to capture a large amount of details and even colors.
M13 on Hercules
Object: M13 – NGC6205
Class V globular cluster (Note 1)
Location: in the constellation of Hercules (Hercules: Her)
AR = 16h 39.9m
dec = + 36º36´
Magnitude: 5.7 (> 12 for its components)
Dimensions: 17´
It is the most famous globular cluster in the boreal hemisphere, cited by Halley in 1715 and observed by Messier in 1764 as a rounded , bright nebula , brighter in the center and less clear at the edges. It was Herschel in 1787 the first to resolve it into stars and reveal its true nature as a cluster.
With a magnitude of 5.7, M13 ranks 5th in luminosity among globular clusters , second only to M4, M5 and M22. It is easy to find it on the western side of the Hercules quadrilateral , between eta and dseta Her, somewhat closer to the first.
Visually M13 is clearly identifiable to the naked eye in a serene and dark night, with small binoculars it shows us as a tiny ball within a field of faint stars and with a refract of 60 mm it still appears nebulous and without resolution, although with a marked center brighter than the periphery. The spectacle is already impressive with instruments of more than 110 mm showing a myriad of stars that cover more than 12 ‘in diameter, forming a nebulous sub-focus. With low magnification it is possible to distinguish the nucleus from the surrounding luminous halo. To the south extends a chain of more than 15 components in a curved trajectory, very evident in photography.
The best resolution is achieved with apertures from 150 mm . Several hundred stars up to magnitude 14 appear tightly grouped framing the uniformly luminous and dense central region.
Only some configurations and chains close to the periphery seem to alter the spherical shape, which at 150x is more evident in the ESE area, where a 5×1 ‘“arm” emerges. With larger openings the show is indescribable with hundreds of stars everywhere making it difficult to count. Perhaps of note is a slightly higher density in the N and O zones of the nucleus.
It is located about 25,000 light-years from Earth and appears to contain at least one million stars , more than 90% within a radius of 32 light years from its center and with an average magnitude of 12. Its age has been calculated. in about 14 billion years.
M64 at Coma Berenices
Object: M64 – NGC4826
Sb-type spiral galaxy (Note 2)
Location: in the constellation of Cabellera de Berenice (Coma Berenices, Comae Berenices; Com) (Note 3)
AR = 12h 54.3m
dec = + 21º57´
Magnitude: 8.5
Dimensions : 9.3 ”x 5.4” inclined 60º with respect to the meridian
This splendid galaxy is one of the few whose magnitude allows us to glimpse it with less powerful optics . Discovered in 1779, its cataloging underwent numerous variations, going from a “nebula”, a “well-defined tenuous cluster”, to the definitive spiral galaxy.
To locate it, it is convenient to start from Vindemiatrix (epsilon Virginis), and move the telescope in the N direction until finding the pair formed by 36 and 38 Com, of magnitude 4 and 5 respectively. Moving about 4º towards the NNE again, 35 Com will be discovered, of magnitude 4.5 just over 1º from M64. With a good search engine the galaxy will immediately be distinguished as a nebula ball with a bright center .
M64 is observable with binoculars of 40 or 50 mm aperture, with about 20×70 it shows a bright nucleus and an elliptical halo oriented from NW to SE , and with telescopes of up to 150 mm aperture its full extent is perceived. The nucleus appears almost pinpoint and very luminous, similar to the 11.5th magnitude star seen near 4’N of the galaxy. The external halo appears dim and hazy up to 300 mm openings, but to differentiate the compact and slightly widened spiral arms, more openness and a sky in perfect condition are necessary.
But the most interesting feature of this galaxy is the “Black Eye”, an imposing dark cloud of dense dust that almost completely absorbs the light from the upper part of the nucleus.. Barely distinguishable by direct observation, this galaxy becomes one of the most prized trophies for the celestial photographer, albeit with long exposures of no less than 15 minutes and hypersensitive film.
Although cataloged within the Virgo Cluster, it is not actually part of it since it is closer to us, between 11.5 and 19.5 light-years, but since supernovae have never been observed, we do not have an acceptable reference.
M57 at Lyra
Object: M57 – NGC6720 (Annular Lyre Nebula)
Location: In the constellation of Lyra (Lyra, Lyrae; Lyr)
AR = 18h 51.7 m
dec = + 32º 58 ‘
Magnitude: 9
Dimensions 80 ”x 60”
We are facing one of the most celebrated celestial objects for its peculiar morphology . The French astronomer Darquier anticipated Messier himself a few days in his discovery while observing the comet of 1779 and defined it as “very faint, but perfectly defined; it is as big as Jupiter and it looks like a planet that is going out. ” Messier describes it on January 31 of that year and states that it is made up of tiny stars. Thanks to the recently discovered spectroscopy, in 1866 its gaseous composition was confirmed. Its particularity lies in its oval shape that Herschel described with a dark eccentric space inside that gives it the shape of a flattened ring. Only in the middle of the 19th century did the power of the telescopes make it possible to discern the faint central star that completes the magnificent ensemble.
It is a very easy object to locate because Vega (alpha Lyr, 1st magnitude) is the second brightest star in the sky and presides over the view of the sky in spring and summer. M57 is just 7º SE of it, between beta and gamma Lyr, although 1/3 closer to the first. It is barely distinguishable with binoculars like a 9th magnitude star. It is already visible with small refractors but the famous central gap is hardly noticeable, not even with 100 mm reflectors at low magnification. It may disappoint the beginner who is familiar with splendid full-color photographs and will hardly notice a faint oval stain but no trace of the characteristic ring. It is with apertures of 150 to 200 mm where it shines in all its splendor. At 75x the ring appears with the dark central hollow very evident, although of a lighter tone than the background of the surrounding sky. It is possible to appreciate a certain coloration of the whole in a weak greenish-white tone. Only with large openings, a lot of patience and a sky in perfect conditions of transparency will the irregularities of the ring be appreciated , made up of two bright semi-arches in the center and dimmer at the ends that meet. The central 12-magnitude star is hardly visible almost 1’E from the geometric center.
M57 is considered the prototype of a planetary nebula, however it is not at all. It is the final phase of the life of a medium-sized star that passes into a variable state in which it violently expels the outer layers of its atmosphere to form a nebula. Measurements taken in the last 50 years indicate that if its expansion had been constant, it would have been born about 5500 years ago.
It is undoubtedly one of the most appreciated models for astronomical photography since it shows an interesting and very characteristic structure and an appreciable range of colors . As the central star is one of the hottest known (about 120,000ºC), the ionization of the inner layers is more intense, where oxygen and nitrogen stand out in an intense blue color, while the outer part only hydrogen receives enough energy to shine with reddish tones.
M3 in Canes Venatici
Object: M3 – NGC5272
Class V globular cluster
Location: in the constellation of Hunting Dogs or Sighthounds (Canes Venatici, Canun Venaticorum; CVn)
AR = 13h 39.9m
dec = + 28º38´
Magnitude: 6.4 (> 13 for its components)
Dimensions: 16.2 ‘
We are facing one of the less spectacular constellations in the northern sky in which, however, the magnificent clusters M3 and M53 stand out in their own light. M3 was discovered by Messier in 1801 but he recorded it as a simple nebula . Again Herschel (1) was the one who gave it its definitive identity as a “very bright globular cluster”.
To find it we have to look halfway between Arturo (alpha Bootis, 1st magnitude) and Cor Caroli (alpha Canum Venaticorum, 3rd magnitude) .
Easily identifiable by binoculars or a simple telescope finder, its appearance is similar to M13 (in Hercules) in luminosity and shape, although it exceeds it in size by about 20×70. It is noteworthy certain slight asymmetries that give it a more granular appearance than its Herculean counterpart. These details are already appreciated with a 60mm refractor, and it allows solving some individual stars with 100mm apertures . The whole is diffuse but the compression of the nucleus sharpens at about ¾ of the radius and continues towards the center. On the periphery you can see chains of stars that are projected outwards, giving the appearance of filaments from a decomposing ball, like a jellyfish. With large apertures it is advisable to observe it with low magnificationwhere the core occupies 1/3 of the total dimensions of M3. At 150x it is possible to discern no less than 200 stars of magnitude 12 to 14, mainly in the periphery since the density of the nucleus is very high. The southern region of the cluster has a greater wealth of stars. Regarding the stellar projections, it is possible to appreciate three main ones: The largest to the north and the other two minor to the east and northwest.
The total diameter is about 16 ‘and with the sky in low visual conditions it gives the impression of being a comet with an extensive coma and an almost negligible tail to the north. Studying the magnitude of its many Cepheid variables, it has been estimated that M3 is about 35 light-years from us.
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M104 in Virgo
Object M104 – NGC4594
Spiral galaxy (“del Sombrero”)
Location: In the constellation Virgo (Virgo, Virginis; Vir)
RA = 12h 37.4 m,
dec = -11º 21 ‘
Magnitude: 8.3
Dimensions: 8.9’x 4.1’
It was discovered on May 11, 1781 by Messier, who described it as a “very faint nebula . ” Although the original Catalog only contained fifty objects, at the end of the 19th century it was decided to add this nebula with the number 104 since the discoverer himself recorded its coordinates although he did not consider it significant. William Herschel discovered this object as a double filament of light, the northern one more luminous than the bottom through his 180 cm telescope. In 1897 astrophotographer Isaac Roberts was the first to discover, with a 90-minute exposure, that in reality M104 was not a strange elliptical galaxy but a spiral seen in profile .
It is not easy to locate since it is in a dark and star-poor area of the sky . Starting from Spica (alpha Virginis, 1st magnitude), you have to move the field of vision about 10º further to the East, halfway between the constellations Virgo and Corvus. From the delta star Corvi there is a series of faint stars that form a chain leading to M104.
With 10×50 binoculars it is visible as an extensive but faint and shapeless spot . At about 20×70 you can already see an elongated shape from E to O but it barely stands out as an extensive nebula. Through small aperture telescopes, a 60 mm refractor for example, the nucleus and halo are already evident . To delve into detail, apertures of no less than 100 mm are needed, although the central dark band is perceived as diffuse and without detail. This characteristic band is the part of the spiral arms richest in dust and gas that appears towards us practically on the edge, with just 6º of inclination. Only with clean and clear sky and with indirect vision this equatorial band is clearly dark and contrasted under the central bulb. It is very well perceived in contrast to the nucleus but gradually disappears at the ends. Altogether it gives the appearance of a very elongated normal galaxy under which a second parallel galaxy of dimension 1/3 of the superior one is glimpsed. It is easy to calculate the magnitudes of each area because at about 2’al NNE of the nucleus there is a star of magnitude 13 and in the vicinity only two other stars of magnitude 9 stand out.
By observing the luminosity of some of its globular clusters, their distance from Earth was determined to be about 40 million light-years . According to Holmberg M104 is the most massive of the Messier Catalog galaxieswith no less than 1.3 trillion solar masses and a diameter of between 90,000 and 130,000 light-years. Although it is located in an area poor in bright stars, it is rich in galaxies of all kinds since it is part of the Virgo Cluster, an agglomeration of galaxies gravitationally linked to each other. In reality our own Milky Way is a peripheral galaxy of this great supercluster that we can see in an area of 6º radius (Note 4) within the constellation Virgo. It has gone down in history because at the beginning of this century (Note 5) its recession speed was calculated at 1180 km / s and a rotation of 330 km / s at a distance of 2 ‘from the nucleus. These data supported the theory of the “island universes”,
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Grades:
(1) In Herschel’s classification the richest and most compact clusters belong to class I , up to class XII with widely dispersed globular aggregations.
(2) In the Hubble classification of galaxies, he establishes three basic types according to their geometry:
E – elliptical (18% of the total), with subclasses that denote increasing flattening between 0 for spherical galaxies and 7 for relative dimensions of 3: 1
S – spirals (including an SB subclassification for barred spirals), with subclasses according to the relative importance of the nucleus (a, very strong; b, medium; c, very weak)
I – irregular (4% of those observed)
According to this classification the Andromeda Galaxy is of the Sc type.
(3) The constellations are designated by their classical Latin name , providing the nominative and genitive cases, in addition to their abbreviation.
(4) Equivalent to about 500 times the apparent surface of the Sun or Moon as seen from Earth .
(5) As everyone knows, the 21st century will begin on January 1, 2001, right? .
