Deep-sky objects are celestial objects that exist outside our solar system. There are three major types of deep-sky objects - nebulae, star clusters, and galaxies. The word nebula is Latin and means "cloud." A nebula (plural = nebulae), therefore, is a cloud of gas and dust in space. Three types of nebulae exist: bright, dark, and planetary. This gallery showcases some of the Deep Sky Objects I have captured.
To put things in perspective with respect to the distances of space, if one were to build an exact scale model of our Solar System from the Sun to Neptune with each planet in its full orbit, and the Earth the size of a blue marble, one will need 7 miles of space!
“As we got farther and farther away, the earth diminished in size. Finally it shrank to the size of a marble, the most beautiful marble you can imagine… seeing this has to change a man.”
— James Irwin, Apollo 15
Orion Nebula
Once again photographing the Orion Nebula (also known as Messier 42, M42, or NGC 1976) but this time from a Dark Sky location - Tumling in the Singalila National Park in West Bengal - and getting far more detail in far less time than I can ever get from a light polluted sky. I have included my earlier photo below as a comparison. Read more about the International Dark Sky Association & the International Dark Sky Sanctuaries.
The Orion Nebula has inspired more adjectives than any other nebulae. None, however, do real justice to this great mass of swirling, pale green, chaotic gas. Even “overpowering” is a most inadequate word when the nebula is seen in a really dark sky. This is the view I had on the night of 11th November 2021.
The lower bright star on the right of the nebula is the third magnitude (2.77) Na'ir al Saif, Arabic for "the Bright One in the Sword," the name "Saif" (sword) wrongly transferred to Kappa Orionis (Na'ir al Saif receiving the Iota designation from Bayer). A class O (O9) giant, and one of the hottest and bluest stars that make Orion's classical figure, Na'ir al Saif shines with a temperature of 31,500 Kelvin from a quite- uncertain distance of 1300 light years, giving it a luminosity (corrected for ultraviolet radiation and a bit of interstellar dust absorption) of 14,000 times that of the Sun.
Orion Nebula is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. M42 is located at a distance of 1,344 ± 20 light years and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light years across. It has a mass of about 2,000 times that of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula.
The Orion Nebula is one of the most scrutinised and photographed objects in the night sky, and is among the most intensely studied celestial features. The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust. Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo-ionizing effects of massive nearby stars in the nebula.
There has been speculation that the Mayans may have described the nebula within their "Three Hearthstones" creation myth; if so, the three would correspond to two stars at the base of Orion, Rigel and Saiph, and another, Alnitak at the tip of the "belt" of the imagined hunter, the vertices of a nearly perfect equilateral triangle with Orion's Sword (including the Orion Nebula) in the middle of the triangle seen as the smudge of smoke from copal incense in a modern myth, or, in (the translation it suggests of) an ancient one, the literal or figurative embers of a fiery creation.
Exif: 7D Mark ii; EF 100-400mm f/4.5-5.6L IS II USM Lens at 400mm and f/5; Exposure: 90 sec; ISO: 3200; WB: 5000K
Tracked with the Sky Watcher Star Adventurer and using the Optolong L-eNhance filter - Find the entire kit in my bag.
A total stack of 27 light frames and 1 dark frame to remove noise using Starry Sky Stacker, under Bortle 1 skies, color corrected & processed in Photoshop. Total tracking was between 2100 hrs and 2303 hrs and I didn’t really need to use the Sky Safari app because the nebula was visible with the naked eye. My thanks to the Firefox Expeditions India team - Sourav Mondal & his great team - for their patience, curiosity and indulgence.
Star map and framing using Sky Safari
Orion Nebula
This is the view I had on the night of 18th & 19th November 2020 from a Bortle 8-9 sky.
Exif: 7D Mark ii; EF 100-400mm f/4.5-5.6L IS II USM Lens at 400mm and f/5.6; Exposure: 120 sec; ISO: 2500; WB: 5500K
Tracked with the Sky Watcher Star Adventurer and using the Optolong L-eNhance filter - Find the entire kit in my bag.
A total stack of 20 light frames and 17 dark frames using Starry Sky Stacker, under Bortle 9 skies, stacked & processed on Siril. Total tracking was between 2100 hrs and 0200 hrs.
Illustrated below is the Moon Phase on the night - it had just set as I started imaging - and the star map used to find and frame. I also use StarWalk2 and Sky Safari to support the search and track.
Star map and framing using Sky Safari
Pleiades
The Pleiades, also known as the Seven Sisters and Messier 45, are an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. It is among the star clusters nearest to Earth, it is the nearest Messier object to Earth, and is the cluster most obvious to the naked eye in the night sky.
The constellation Taurus as it can be seen by the naked eye. The constellation lines have been added for clarity.
In Hinduism, the Pleiades are known as Krittika and are associated with the war-god Kartikeya.
The earliest-known depiction of the Pleiades is likely a Northern German Bronze Age artefact known as the Nebra sky disk, dated to approximately 1600 BC.
Exif: 7D Mark ii; EF 100-400mm f/4.5-5.6L IS II USM Lens at 400mm and f/5.6; Exposure: 120 sec; ISO: 1000; WB: 5500K
Tracked with the Sky Watcher Star Adventurer and using the Astronomik CLS light pollution filter - Find the entire kit in my bag.
A total stack of 46 light frames and 30 dark frames using Starry Sky Stacker, under Bortle 8-9 skies, color corrected in Lightroom & processed in Photoshop. Total tracking was between 2230 hrs and 0300 hrs.
Illustrated below is the Moon Phase on the night. I also use StarWalk2 and Sky Safari to support the search and track.
The cluster is dominated by hot blue and luminous stars that have formed within the last 100 million years. Reflection nebulae seen here around the brightest stars were once thought to be left over material from the formation of the cluster, but are now considered likely to be an unrelated dust cloud in the interstellar medium through which the stars are currently passing.
Computer simulations have shown that the Pleiades were probably formed from a compact configuration that resembled the Orion Nebula featured above. Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighbourhood.
Together with the open star cluster of the Hyades the Pleiades form the Golden Gate of the Ecliptic. This is the view of the Pleiades I had on the night of 21st & 22nd November 2020 from a Bortle 8-9 sky.
The name of the Pleiades comes from Ancient Greek. It probably derives from plein ("to sail") because of the cluster's importance in delimiting the sailing season in the Mediterranean Sea: "the season of navigation began with their heliacal rising". However, in mythology the name was used for the Pleiades, seven divine sisters, the name supposedly deriving from that of their mother Pleione and effectively meaning "daughters of Pleione". In reality, the name of the star cluster almost certainly came first, and Pleione was invented to explain it.
They have been known since antiquity to cultures all around the world, including the Celts, the Hawaiians (who call them Makali), the Māori (who call them Matariki), Aboriginal Australians, the Persians, whence in Hindi & Urdu (who called them Parvīn or Parvī), the Arabs (who called them al-Thurayya), the Chinese (who called them mǎo), the Quechua, the Japanese (who called them Subaru), the Maya, the Aztec, the Sioux, the Kiowa, and the Cherokee.
The opening speech is as a tribute to Leonard Nimoy and the Star Trek series for sparking the interest in space.
Taurus, the head of the Bull & the Hyades Star Cluster
The constellation Taurus is hard to miss as he charges through the northern winter sky. "The bull" is one of the most noticeable constellations and one of the oldest documented constellations, with descriptions of Taurus going as far back as the early Bronze Age. Taurus is most famous for its red giant star, Aldebaran, seen here on the bottom left, as well as a star cluster known as the Pleiades, featured above.
Taurus is one of the 12 constellations of the zodiac, first catalogued by the Greek astronomer Claudius Ptolemy in the 2nd century CE.
Taurus is depicted as a bull, within which the Hyades cluster forms the bull's head. North-east of this, the stars β-Tau and ζ-Tau mark the tips of the bull's horns. Close to the bull's right horn lies another remarkable deep sky object, the Crab Nebula (M1), which is the remnant of a supernova explosion seen by Chinese observers in 1054.
The age of the Hyades is estimated to be about 625 million years. The core of the cluster, where stars are the most densely packed, has a radius of 8.8 light-years (2.7 parsecs), and the cluster's tidal radius – where the stars become more strongly influenced by the gravity of the surrounding Milky Way galaxy – is 33 light-years (10 parsecs). However, about one-third of confirmed member stars have been observed well outside the latter boundary, in the cluster's extended halo; these stars are probably in the process of escaping from its gravitational influence.
The constellation Taurus as it can be seen by the naked eye. The constellation lines have been added for clarity and the red giant Aldebaran listed.
The red giant star Aldebaran is 65 light-years from Earth. It is the brightest star in the constellation and the 14th brightest star in the sky, according to EarthSky.org. Aldebaran also forms part of a V-shaped asterism, or group of stars, that is called the Hyades; this shape makes up the bull's face.
The Orange-hued Aldebaran is often described as glaring at Orion, the hunter, a constellation that lies just to the star's southwest and one my first deep sky objects. The planetary probe Pioneer 10 is moving in the general direction of that star, expected to make its closest pass by Aldebaran in roughly 2 million years, according to NASA.
In addition to the Hyades, the constellation's other major star cluster is the Pleiades, featured above, which consists of seven stars that rest on the bull's shoulder. It is said that these stars represent the Seven Sisters, daughters of Atlas and Pleione from Greek mythology.
Together with the Pleiades the Hyades form the Golden Gate of the Ecliptic. This is the view of the Hyades I had on the night of 10th & 11th December 2020 from a Bortle 8-9 sky.
When Zeus fell in love with the Phoenician Princess Europa, he transformed himself into a white bull with golden horns named Taurus and carried Europa away to Crete.
Hyades is also depicted on the shield of Achilles in Book 18 of the Iliad - read about the shield of Achilles.
Taurus also has a number of famous deep sky objects, among them the supernova remnant Messier 1 (the Crab Nebula), Hind’s Variable Nebula (NGC 1555), the colliding galaxies NGC 1410 and NGC 1409, the Crystal Ball Nebula (NGC 1514), and the Merope Nebula (NGC 1435).
Exif: 7D Mark ii; EF 100-400mm f/4.5-5.6L IS II USM Lens at 182mm and f/5; Exposure: 120 sec; ISO: 1000; WB: 5500K
Tracked with the Sky Watcher Star Adventurer and using the Optolong L-eNhance filter - Find the entire kit in my bag.
A total stack of 94 light frames and 33 dark frames using Starry Sky Stacker, under Bortle 8-9 skies, color corrected in Lightroom & processed in Photoshop. Total tracking was between 2230 hrs and 0300 hrs.
Illustrated below is the Moon Phase on the night. I also use StarWalk2 and Sky Safari to support the search and track.
The sky when I finished my session and the Hyades was past the zenith.
A short clip of the stars and drawing the head of the bull.
The Horsehead & Flame Nebula
The Horsehead Nebula (also known as Barnard 33) is a small dark nebula in the constellation Orion. The nebula is located just to the south of Alnitak, the eastern most star of Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex. It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of the much larger, active star-forming H II region called IC 434. The Horsehead Nebula is approximately 422 parsecs or 1,375 light-years from Earth. It is one of the most identifiable nebulae because of its resemblance to a horse's head.
The Flame Nebula is visible just to the left of the Horsehead, while the bright star between the two is Alnitak, the third star in Orion's Belt. The Horsehead Nebula lies 1,500 light years distant towards the constellation of Orion.
Exif: 7D Mark ii; EF 70-200mm f/2.8L IS III USM Lens at 175mm and f/2.8; Exposure: 3.1 min; ISO: 1600; WB: 4750K
Tracked with the Sky Watcher Star Adventurer and using the Astronomik Hα 12nm filter with a 85% waning gibbous Moon to the left of the frame. Find the entire kit in my bag.
A total stack of 69 light frames and 20 dark frames using Starry Sky Stacker, under Bortle 8-9 skies, color corrected in Lightroom & processed in Photoshop. Total tracking was between 2330 hrs and 0500 hrs but unfortunately not all the frames were usable.
Illustrated below is the Moon Phase on the night and the star map used to find and frame. I also use StarWalk2 and Sky Safari to support the search and track.
Star map and framing using Stellarium