The Great Andromeda Galaxy.
Imaged in visible light ... R ... G ... B .... plus Hydrogen-alpha. 
The Ha contribution can be seen as the deep reddish clusters, in the spiral arms of the galaxy and in the reddish cast of the bright core, all of which reveal star creation regions.
This image represents just over 10 hours in total exposure.  It is a 2-panel mosaic.
The galaxy's name stems from the area of Earth's sky in which it appears, the constellation of Andromeda, which itself is named after the princess who was the wife of Perseus in Greek mythology.

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◉  The Milky Way and Andromeda galaxies are expected to collide in around 4–5 billion years, merging to potentially form a giant elliptical galaxy or a large lenticular galaxy.
  ◉  The Andromeda Galaxy is among the brightest of the Messier objects, and is visible to the naked eye from Earth on moonless nights, even when viewed from areas with moderate light pollution.
 ◉  It was mentioned as early as 965 ce, in the Book of the Fixed Stars by the Islamic astronomer al-Ṣūfī.
 ◉ Only in the 1920s did the American astronomer Edwin Powell Hubble determine conclusively that the Andromeda was in fact a separate galaxy beyond the Milky Way.

The Horsehead Nebula and the Flame Nebula
In the winter constellation Orion, you can see the famous Horsehead Nebula, to the right of centre in this image, and then to the left, the equally famous Flame Nebula
This image was collected over several hours and, again, this is a visible light image -- these are the real colours ... just look at that red reflection nebulosity behind the horsehead.
Note, also, the star colours .... older, tired stars are reddish or orange, while younger, more vibrant stars are showing as blue or even white, in colour.

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 ◉  The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright emission nebula.
Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will surely alter its appearance.
◉  The emission nebula's orange color is caused by electrons recombining with protons to form hydrogen atoms. Toward the lower left of the image is the Flame Nebula, an orange-tinged nebula that also contains intricate filaments of dark dust.
◉  Several prominent reflection nebulas are visible:  NGC 2023 is just to the lower left of the Horsehead nebula. Each glows primarily by reflecting the light of their central star.
◉  The bright star, left of centre, is Alnitak, the left-most star in Orion's belt. It is actually a triple star system with its primary star being a hot blue supergiant.
Like many star names, Alnitak's etymology is Arabic ... Al Nitak or Alnitah, meaning "the girdle".

This region is a favourite for astrophotographers ... it's easy to see why. 

The Great Orion Nebula - Messier 42
Another favourite, found within the constellation Orion, The Hunter.  This spectacular nebula is actually naked-eye visible from most northern locations - even within the light dome of cities.
The Orion Nebula is one of the most scrutinized 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.

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◉   Astronomers have directly observed protoplanetary discs and brown dwarfs within the nebula, 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 of Central America may have described the nebula within their "Three Hearthstones" creation myth;
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.
◉  The first published observation of the nebula was by the Jesuit mathematician and astronomer Johann Baptist Cysat of Lucerne in his 1619 monograph on comets.
He made comparisons between it and a bright comet seen in 1618 and described how the nebula appeared through his telescope as:

" ...  one sees how in like manner some stars are compressed into a very narrow space and how round about and between the stars a white light like that of a white cloud is poured out ..."

The Gygnus Wall
High in our summer skies, at northern latitudes, this busy cosmic neighbourhood is another stunner.  Dust, light, colours .... all part of our universe.
This image was collected, over several hours, using special filters which collect light emitted from ionized Hydrogen, ionized Oxygen and ionized Sulphur.
Cygnus is the high-summer constellation also known as The Swan.

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◉  The Cygnus Wall is a segment of the North America Nebula (NGC7000) and is the region of the nebula with the most concentrated stellar formation.
◉  The ridge here is approximately 20 light years long and is a huge star forming region.

The Pleiades .... The Seven Sisters ..... Messier 45
Another Fall-Winter favourite. This area of reflection nebulosity was imaged in visible light.
The Pleiades, also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus.

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 ◉  At a distance of about 444 light years, it is among the nearest star clusters to Earth.
◉   It is the nearest Messier object to Earth, and is the most obvious cluster to the naked eye in the night sky.
◉  The name of the Pleiades comes from Ancient Greek: Πλειάδες. 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".
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'First Light'
 

ET at home ... The Elephant Trunk Nebula and its region
Another late-in-the-year favourite.  Images in Hydrogen alpha, Oxygen III and Sulphur II light ... over several hours.
This image was actually the 'First Light' for Cassiopeia -- the first official and complete image collected by Cassiopeia, once all of her rigorous testing was concluded.
The Elephant's Trunk Nebula is a concentration of interstellar gas and dust within the much larger ionized gas region IC 1396 located in the constellation Cepheus about 2,400 light years away from Earth.
The piece of the nebula shown here is the dark, dense globule IC 1396A; it is commonly called the Elephant's Trunk nebula because of its appearance in certain light wavelengths,
where there is a dark patch with a bright, sinuous rim.

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 ◉  The Elephant's Trunk Nebula is now thought to be a site of star formation, containing several very young (less than 100,000 yr) stars that were
discovered in infrared images in 2003. Two older (but still young, a couple of million years, by the standards of stars, which live for billions of years) stars are present in a small, circular cavity in the head of the globule.
Winds from these young stars may have emptied the cavity.
◉   The combined action of the light from the massive star ionizing and compressing the rim of the cloud, and the wind from the young stars shifting gas from the center outward lead to
very high compression in the Elephant's Trunk Nebula. This pressure has triggered the current generation of protostars.

Beta testing Before the official  'First Light'  image, there was about a month's worth of installation and testing. These Beta/testing images' data were collected on Aug. 27 and Aug. 28 --  more than a full month before the official  full-colour   'First Light'   image, which was on Sept. 29. The  sub-exposures, which make up these images, were taken in Hydrogen alpha light ... and were just part of the rigorous testing regime of the observatory and its instrument and computers. These data were noticed some months later ... and it was realized that there might be "enough" data to actually turn out some kind of image or two ..... not bad for what was supposed to be throwaway tests.
The Pelican Nebula The Pelican Nebula, found in the constellation Cygnus (The Swan) is a strong region of Hydrogen alpha emissions, which are said to bear a strong resemblance to a pelican. This nebula is much studied because it has a particularly active mix of star formation and evolving gas and dust clouds.	The Crescent Nebula The Crescent Nebula is also found in the constellation Cygnus (The Swan). It is formed by the fast stellar win from a powerful star colliding with and energizing the slower moving wind ejected b the star whe it became a red giant about 250,000 years ago. The result of the collision is two spectacular show waves, one moving outward and the other inward.	The Heart Nebula The Heart Nebula is so-named because it looks like a cosmic heart. This image, which is only part of this nebula represents 6 X 1-min. exposures. The camera's sensor was running at 0C, a full 15 degrees warmer than it should have been, still excellent.

The Pacman Nebula - NGC281
Colloquially, NGC281 is known as the Pacman Nebula, because of its resemblance to the video game character.
NGC281 is a bright emission nebula in the northern constellation Cassiopeia, which is in our Milky Way's Perseus Spiral Arm.

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◉  This deep space object (DSO) is slightly smaller than a full Moon. It is also associated with the open cluster of stars catalogued as IC1590.
◉  This nebula was discovered in 1883 by Edward Emerson Barnard, an eminent American astronomer.
◉  In the 1880s, philanthropist and businessman Hulbert Harrington Warner offered $200 per discovery of a new comet.
Barnard, who grew up impoverished in Tennessee, discovered a total of five, in the years immediately following his marriage. He used the money to build a house for himself and his wife.

 

The Triangulum Galaxy - Messier 33
The Triangulum Galaxy is a spiral galaxy 2.73 million light-years from Earth in the constellation Triangulum.
It can be seen with 20-20 vision from a dark sky site and it s likely the farthest permanent entity visible without magnification.

It is catalogued as Messier 33 or NGC (New General Catalogue) 598. With the D25 isophotal diameter of 18.74 kiloparsecs (61,100 light-years),
the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way. It is one of the most distant permanent objects that can be viewed with the naked eye.

The galaxy is the smallest spiral galaxy in the Local Group (although the smaller Large and Small Magellanic Clouds may have been spirals
before their encounters with the Milky Way), and is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due
to their interactions, velocities, and proximity to one another in the night sky. It also has an H II nucleus.

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◉  The Triangulum Galaxy's diameter is approx. 61,100 light-years.
◉  It is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy (see image above, and the Milky Way, our home galaxy).
◉  It is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities, and proximity to one another in the night sky.
◉  It also has an H II nucleus. The HII presence/activity can be seen in the above image as the reddish clusters visible in the spiral arms and also bu the faint reddish hue over the bright core.

The Rosette Nebula - Caldwell 49
In 'false colour' - Narrowband filtered light



There is a cluster of stars in the centre of this nebula, which is known as NGC2244. It is these stars which provide the energy to make this nebula 'glow' for us.
The entire region is a strong source of light in the red spectral lines, hence its strong signal for Hydrogen-alpha astronomy. It is also a stellar nursery.
This late-Autumn, Winter cosmic citizen is about 5.200 light years from Earth.   If you are familiar with the constellation Orion -- a favourite -- go to
the top two stars in Orion (Betelgeuse and Bellatrix) and then go to the left about the same distance those stars are from each other ... and you will be looking at the region of the sky where the Rosette Nebula is found.
 The Rosette Nebula is the largest 'blossom' in any garden ... it is approx. 135 light years in diameter.

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◉  This DSO (Deep Space Object) was imaged in narrowband ... which is not normal light, for human perception.  In this particular set of data .... several hours worth of exposure
with a specialized astro camera ... the light captured is from ionized Hydrogen (wavelength 656nm) , ionized Oxygen (two spectral lines, wavelengths 496nm and 501nm)
and ionized Sulpher (wavelength 672nm), with respective bandwidths of 3.5nm, 4nm and4 nm.
The camera images in Black & White only, and the image date from these ultra-specialized filters is processed with astro software.  During processing, the Ha, OIII and SII data can be
ascribed certain 'colour channels' -- which produce a final result with a certain colour palette.
If you then reprocess the same data but ascribe the date to different 'colour channels', the final results can be completely different.
The main image, above, is described as combination of HSS -- Hydrogen Sulpher Sulper
Below, are four other combinations, from the same set of data, processed differently.

Oxygen Hydrogen Hydrogen

Sulphur Hydrogen Oxygen The Hubble Palette

Sulphur Hydrogen Oxygen with the Green channel removed

The Soul Nebula - Westerhout 5
( Also: Sharpless 2-199 and LBN 667 )

The Soul Nebula is a massive star-formation region within the constellation Cassiopeia.
Those large cavities visible in this image were created by radiation and winds from the region's massive stars. According to the 'triggered star formation theory',
the creation of these cavities pushed gasses together causing the creation of successive generations of new stars.  (More on this subject here:  STAR FORMATION )
The Soul Nebula, most of which is in this image, is very close to the Heart Nebula -- which is really closely shaped like a heart.
With a wider field of view, astrophotographers can capture both of these Deep Space Objects (DSOs) in the same image.  Together, they are poetically referred to as 'The Heart and Soul'.
There is an image of the Heart Nebula elsewhere on our companion astro website, here:  http://galileostelescope.net/
This image is a total exposure of several hours, in light from ionized hydrogen, from ionized sulphur and ionized oxygen.

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◉  Here is a link to a 6-min Wikipedia video on 'The W5 Stellar Blast Furnace'   https://en.wikipedia.org/wiki/File:The_W5_Stellar_Blast_Furnace.ogv
◉  Many stars in this region are thought to be a few million years old. Our Sun, by comparison, is almost 5 billion years old.
◉ The Soul Nebula is about 100 light years in length.
◉ The Soul Nebula is about 5x the size of a full Moon, in length.

The Soap Bubble is actually a planetary nebula (which has nothing to do with planets, by the way), which was discovered in 2007.
Coincidentally, and unknown to me at the time, some of this data was collected on the 15th anniversary of amateur astronomer Dave Jurasevich's actual discovery.
Jurasevich, while being the Director of the Mt. Wilson Observatory, outside Los Angeles, California, used a (serious) amateur telescope in his discovery.

◉  The unique brain-like shape of this object is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163)
colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago

The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy 21 million light-years (6.4 megaparsecs) away from Earth in the constellation Ursa Major.
It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.
This stunning galaxy is a favourite with astrophotographers.

This image represents about 10.5 hours of exposure in  R  G  B  & H-alpha light,  starting May 20, 2023.

Now, this date is significant -- because unknown to Connie and I at the time (we were both at our observatory at this time) a star had gone 'supernova' in this galaxy less than 24 hours earlier. 
So, we collected several hours of imaging date on this galaxy without knowing that we had also image a star blowing up. In fact, we were collecting image data on it
at the same time as the Zwicky Transient Facility (ZTF), in California, was actually confirming the supernova.
What are the chances of this ....?     Astronomical!
Think about what a supernova means .... that star likely had planets around it before it exploded ....

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◉   Supernova hunter Koichi Itagaki, from Yamagata, Japan, first spotted the explosion, which was confirmed the following day (May 20) by telescopes of the Zwicky Transient Facility (ZTF) in California.

 
Messier 13 or M13, also designated NGC 6205 and sometimes called the Great Globular Cluster in Hercules or the Hercules Globular Cluster,
is a globular cluster of several hundred thousand stars in the constellation of Hercules.

Messier 13 was discovered by Edmond Halley in 1714,and cataloged by Charles Messier on June 1, 1764, into his list of objects not to mistake for comets.
Messier's list, including Messier 13, eventually became known as the Messier catalog.

 It is located at right ascension 16h 41.7m, declination +36° 28'. Messier 13 is often described by astronomers as the most magnificent globular cluster visible to northern observers.

About one third of the way from Vega to Arcturus, four bright stars in Herculēs form the Keystone asterism, the broad torso of the hero. M13 can be seen in this asterism 2⁄3 of the way north (by west) from Zeta to Eta Herculis.
With an apparent magnitude of 5.8, Messier 13 may be visible to the naked eye with averted vision on dark nights.  Messier 13 is prominent in traditional binoculars as a bright, round patch of light.
Its diameter is about 23 arcminutes  (almost the size of a full Moon)  and it is readily viewable in small telescopes. At least four inches of telescope aperture resolves stars in Messier 13's outer extent as small pinpoints of light.
However, only larger telescopes resolve stars further into the center of the cluster. 
The cluster is visible throughout the year from latitudes greater than 36 degrees north, with the longest visibility during Northern Hemisphere spring and summer.

About 145 light-years in diameter, M13 is composed of several hundred thousand stars, with estimates varying from around 300,000 to over half a million.
The brightest star in the cluster is a red giant, the variable star V11, also known as V1554 Herculis, with an apparent visual magnitude of 11.95.
M13 is 22,200–25,000 light-years away from Earth, and the globular cluster is one of over one hundred that orbit the center of the Milky Way.[17][18]
 
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◉  Nearby to Messier 13 is NGC 6207, a 12th-magnitude edge-on galaxy that lies 28 arcminutes directly northeast.  
You can see NGC 6207 here, just below the Hercules cluster at about the 5.30 o'clock position ... about halfway from the star cluster to the bottom of this image. It looks like a small, fuzzy cigar-shape of light.
◉  Also, a tiny, tiny galaxy, IC 4617, lies between NGC 6207 and the star cluster.  Again, it is tiny .... you can see it ... go to the halfway point between the centre of the star cluster
and NGC 6207 ... then go up, slightly, and to the right.   It has the same cigar shape as NGC 6207 and has the same alignment.

The Eagle Nebula (catalogued as Messier 16 or M16, and as NGC 6611, and also known as the Star Queen Nebula) is a young open cluster of stars in the constellation Serpens.
It was discovered by Jean-Philippe de Cheseaux in 1745–46. Both the "Eagle" and the "Star Queen" refer to visual impressions of the dark silhouette near the center of the nebula.
This is the same area made famous as the "Pillars of Creation" imaged by the Hubble Space Telescope.
The nebula contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation.
The Eagle Nebula lies in the Sagittarius Arm of the Milky Way.


The Eagle Nebula is part of a huge diffuse emission nebula, or H II region, which is catalogued as IC 4703. This region of active current star formation is about 5700 light-years distant.
A spire of gas that can be seen coming off the nebula in the northeastern part is approximately 9.5 light-years or about 90 trillion kilometers long.

The cluster associated with the nebula has approximately 8100 stars, which are mostly concentrated in a gap in the molecular cloud to the north-west of the Pillars.
The brightest star (HD 168076) has an apparent magnitude of +8.24, easily visible with good binoculars. It is actually a binary star formed of an O3.5V star plus an O7.5V companion.
 This star has a mass of roughly 80 solar masses, and a luminosity up to 1 million times that of the Sun. The cluster's age has been estimated to be 1–2 million years.

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Two images of this nebula are presented here. The first, above, is about 6.5-hours of exposure in H-alpha, OIII, SII, R, G, B and UV-IR Cut-L frequencies of light.
 
◉  ABOVE:  Process in SHO - the Hubble Palette, with RGB stars blended with PixInsight.  All data integrated here.

◉  BELOW:  Processed in Hydrogen-alpha light only, Approx. two hours of exposure.


◉  DATA COLLECTION:  It took four years to collect this data for this image, starting in the summer of 2019. A host of issues repeatedly scuppered the work here.

INCLUDING: ◉   COVID lockdowns, which severely restricted related activities. ◉   The fact that this target is extremely low to the southern horizon, and therefore, only visible for short windows each year. ◉   That fact that this cannot be imaged if there is much Moon in the sky ... which erodes the data collection. ◉   Weather, in general. ◉   Firesmoke .... sadly, a new reality for this part of North America. ◉   Because this extremely-low-to-the-south target is highest late in the night, it best presents during the coldest part of night. This is the time when water condenses most intensely at night, meaning cloud formation.  Tied with this, is the fact that this low target means you are imaging through the equivalent of about 20 atmospheres (as opposed to straight up), which means even very thin cloud formation -- when seen sideways, as when 'on' this target -- can be a showstopper. ◉   Finally ... my own availablity. Bottom line:  Four years in the making.