Figure 1 – Messier 42 – the Great Orion Nebula, Jan. 1 , 2025, Sudbury, MA (c) DEWolf 2025

As I write, I am looking out at a foot of snow; now turning to rain and misery. There are no clear skies, which has been common this winter – drives one to thought. And I am thinking about the deep sky glories of the northern winter sky.

Most dramatic of these is most certainly is Messier 42 the Great Nebula in Orion. This must be called a cosmic marvel and has fascinated astronomers for centuries. But what exactly makes this nebula so captivating? Messier 42 is a massive cloud of gas and dust located in the constellation of Orion, approximately 1,344 light-years away from Earth. It’s the closest region of massive star formation to our planet, making it a perfect laboratory for studying how stars—and planetary systems—are born. The nebula spans about 24 light-years across and contains a vast number of stars at various stages of their life cycle. It is often referred to a stellar nursery, where young stars are born from the surrounding gas and dust.

The Orion Nebula is easy to spot with the naked eye and can be found just below the three stars that form Orion’s “belt.” It is one of the brightest nebulae in the sky, with a distinct, glowing appearance. This is due to the ionized hydrogen gas in the nebula, which emits a characteristic red glow when exposed to the ultraviolet radiation from nearby hot young stars. Seeing the color in deep-sky objects often require the collecting power of a telescope or binoculars.

Within the vast expanse of Messier 42, hundreds of young stars are in the process of being born. The nebula’s high concentration of gas and dust provides the perfect conditions for new stars to form. The energy from the intense ultraviolet light emitted by the newly formed stars heats the surrounding gas, causing it to glow brightly. This interaction between newly born stars and the gas around them creates a stunning cosmic display.

The most massive and brightest stars within the Orion Nebula are located at the nebula’s heart, within a small region known as the Trapezium. These stars are hot, young, and full of energy, and their radiation creates the ionized gases that give the nebula its characteristic glow. Interestingly, some of the stars in the Trapezium are only a few million years old, which is extremely young in stellar terms. Over the next few million years, the Orion Nebula will continue to evolve, with stars being born, dying, and scattering heavier elements into the surrounding space.

With smart telescopes the scene always starts out a bit real-time weak. And then for M42 in particular, the first integrated image of typically ten or twenty seconds comes through and “bam!!!” There’s that word again. You are suddenly greeted with a bright and spectacular image. Let it integrate for a half hour or more and you have a image of beauty. Figure 1 is a 30 min, 180 exposure image on the Celestron Origin, one of my “first light” images. I now would do at least twice as long.

But, you know, I remember as a teenager standing by New York’s East River and wondering what it would be like to see these great Messier objects against an unpolluted sky. It is truly magical!

The Rosette Nebula, Sixty Minute Celestron Origin Image (c) DEWolf 2025.

Today let’s talk about another rose nebula, this one with “bam!” One of the most spectacular sights in the night sky is the Rosette Nebula. Known for its striking beauty and its role as a stellar nursery, this giant cloud of gas and dust captivates astronomers and stargazers alike. The

Rosette Nebula is a large star-forming region located in the constellation Monoceros, about 4,500 light-years away from Earth. It spans about 50 light-years in diameter and is home to a young, open star cluster called NGC 2244, whose stars are just a few million years old. These stars have formed from the gas and dust that make up the nebula.

The nebula’s name, like that of Caroline’s Rose comes from its resemblance to a rose or in this case a rosette, a flower-like shape formed by the nebula’s intricate arrangement of gas clouds. The glowing gas and dust are illuminated by the bright, young stars at the heart of the nebula, giving it the appearance of a cosmic bloom.

At its core, the Rosette Nebula is a stellar nursery, a place where new stars are being born. The intense ultraviolet light from the newly-formed stars heats the surrounding gas and dust, causing the nebula to shine. In some parts of the nebula, the gas is dense enough to collapse under its own gravity, triggering the birth of new stars.

The most massive stars in the nebula have short lifespans and are known to have significant impacts on their environments. These stars emit powerful stellar winds, which can blow away the surrounding gas and dust, creating gaps and holes in the nebula. These energetic winds, combined with the ultraviolet radiation, shape the nebula into the stunning structure we observe today.

At the center of the Rosette Nebula lies NGC 2244, an open star cluster of around 2,000 young stars. These stars formed from the gas and dust that surrounds them, and their bright ultraviolet radiation and strong stellar winds have shaped the nebula into its current form. NGC 2244 is a relatively young cluster, only about 4 to 5 million years old, which is just a blink in the timeline of the universe.

The stars in this cluster are responsible for much of the nebula’s bright, glowing appearance. The cluster itself is held together by gravity, but over time, the stars will drift apart as they age, and the nebula disperses into space.

The Rosette Nebula is composed of both emission nebulae and dark nebulae. The emission nebulae are the parts of the nebula that glow brightly due to ionized gas being energized by the ultraviolet radiation from nearby stars. The most prominent part of the nebula is a vast region of ionized hydrogen gas, known as H II regions. These glowing hydrogen regions make up the majority of the nebula’s brightness.

On the other hand, dark nebulae are dense regions of gas and dust that block the light from stars and other bright nebulae behind them. These dark patches form a striking contrast against the brighter areas of the nebula, adding depth and complexity to the structure.

The image of Figure 1 was taken with my Celestron Origin and is a sixty min exposure composed of 360 ten second frames. You need that to grow the image from a faint cloud with little detail to the relatively high signal to noise image of Figure 1. More on Signal to Noise at a later date, but let’s just say it is key to good astrophotographs.

People always ask me about the color. There is not much monkeying going on with that, just histogram equalization and then a tad of improved color saturation. This is the same as that I do with my bird photographs. More on that subject as well is to come.

I just do want to pose the question. With all this bam is it still sublime? I think that the answer is yes!

Figure 1 – Caroline’s Rose NGC 7789 Open star cluster, Celestron Origin (c) DE Wolf 2024.

Deep-sky objects seem to come in two flavors: the breath-taking and the sublime. I want to talk today about an example of a sublime deep-sky object NGC 7789 referred to as Caroline’s Rose, see Figure 1 – not bam in your face but subtly beautiful nonetheless. . Caroline’s Rose is an open cluster in Cassiopeia ~ 1.6 Billion years old and ~ 7,600 light years away. It was discovered the night of November, 1 1783 by Caroline Herschel, the sister of William. So there’s a story there and that’s part of what makes this stellar white rose sublime.

Caroline Herschel was an astronomical trailblazer. She was born in 1750 in Hanover, Germany. Her early life was shaped by a series of challenges, including an overbearing family dynamic ( her brother rescued her from an overbearing mother, who did not believe in wome’s education.) and an enduring illness that left her small and fragile in stature. Despite these obstacles, Caroline’s mind was a vast universe of curiosity. Her brother, William Herschel, a prominent astronomer in his own right, recognized her intelligence and enlisted her help in his astronomical work.

Caroline’s contributions to science were groundbreaking. She discovered several comets, including the famous Herschel 1, which is now known as Comet 35P/Herschel-Rigollet. She also worked with William Herschel on the first comprehensive catalog of nebulae, helping to expand humanity’s understanding of the night sky. In 1787, Caroline became the first woman to receive a salary as an astronomer from the British government, an achievement that cemented her place in history. Caroline’s story isn’t just about her astronomical achievements. It’s also about resilience, passion, and a deep connection to the world around her. Caroline’s Rose serves as a beautiful tribute to a woman who not only reached for the stars but helped humanity understand them in profound new ways.

Pointing ever to the power and long history of the psychological phenomenon of pareidolia, things that look like in astronomy, the white rose requires some study to discern. Can you make out the petals? Through Caroline Herschel’s life it is a symbol of the revolution that she had launched, really a war against sexism and the confines of the Victorian Age. It is perhaps reminiscent of the medieval War of the Roses, between the Houses of York and Plantagenet. Roses are a symbol of love and for white roses of purity and harmony. It is with sublime, peace, purity that this majestic star cluster hangs beacon in its celestial sphere, reminding us forever of the origins of the astronomy.

Prick not your finger as you pluck it off,
Lest bleeding you do paint the white rose red
And fall on my side so, against your will.

William Shakespeare, Henry the Sixth, Part 1

Figure 1 – The Tarantula Nebula photographed with iTelescope.net’s T30 telescope in Siding Spring Australia (c) DE Wolf 2024

The other form of astrophotography that I have been doing is to control remote telescopes on a fee for basis. I have used Skygems-observatories and iTelescope.net. In general, these offer whatever level or degree of control you want. When you watch step-by-step what the telescope is doing you gain a humbling understanding of the true complexity of the astrophotography process. I typically take my FITS image stack, then register the stack and recombine it into an RGB using astropixel processor. This is topped off with a bit of processing in Adobe Photoshop including the Topaz Photo AI module. The latter being used for noise removal and what is referred to as upscaling. On top of everything else, this approach gives us Northern hemisphere astrophotographer access to amazing telescopes and the Southern celestial sky with its rich deep-sky offerings.

Case in point Telescope, T 30, is located at Siding Spring Observatory is located in New Sout Wales, Australia. It is gorgeous in every sense of the word! It is a Planewave 20″ (0.51m) Corrected Dall-Kirkham Astrograph with an aperture of 508mm and a focal length of 2262 mm, thus f/4 and a FOV of 27.8 x 41.6 arc-mins. Figure 1 above is an RGB created from three 120 second exposure in each RGB color plane of the Tarantula Nebula NGC 2070.

The Tarantula Nebula, also known as NGC 2070, is la star nursery located in the Large Magellanic Cloud (LMC), a neighboring galaxy to our own Milky Way, Stretching across 1,000 light-years and containing some of the most massive stars ever discovered, the Tarantula Nebula is a hotbed of star formation. The nebula’s name comes from its resemblance to a spider’s web, with sprawling filaments of gas and dust woven throughout the region. The nebula’s bright red hue comes from hydrogen gas being ionized by the intense ultraviolet light of these newborn stars. Observations of the Tarantula Nebula with telescopes like the Hubble Space Telescope and the Very Large Telescope have revealed intricate details of the nebula’s structure, including vast pillars of gas and dust and regions, where stars are actively forming.

When you spend time working on a particular object creating an astrophotograph you develop a kind of artistic intimacy with the subject. The same I find is true with bird photography. Once bitten by this particular spider you never forget it!

iPhone image of the Northern Lights, Oct. 10, 2024, Sudbury, MA (c) DEWolf 2024

On the evening of October 10, 2024 I was using my Celestron 8 SE and observing Saturn. I got a cell phone text from TC reminding me that the NWS was predicting Aurorae for that night and to let her know if I saw one. This prompted me to glance North, and wow the entire sky was lit up. The sun is at the high point in its activity cycle and this was one of 2024’s greatest events. Massive storms of charged plasmas being thrown out from the surface.

I have seen many wonderful photos of this event and mine are far from the best. Still they were taken with my cell phone and I am pretty pleased. Indeed, the miracle of the iPhone is further revealed by the unmoving constellation patterns, easily made out.

I want to remind everyone that invariably the Starship Enterprise in its various incarnations flies into a plasma storm. For instance that’s how Startrek Voyager winds up in the Delta Quadrant and how would you like to have to listen to Captain Janeway act tough for 75 years. I mean with all due respect she’s forever barking orders.

So what’s going on here. What’s a plasma? Plasma is often called the “fourth state of matter,” distinct from solids, liquids, and gases. It occurs when a gas is heated to extremely high temperatures or subjected to a strong electromagnetic field, causing its atoms to lose electrons and become positively charged ions. This ionized gas is a mixture of free electrons and ions, making it electrically conductive. Plasma is found in places like the Sun, stars, lightning, and even in fluorescent lights!

Aurorae, also known as the Northern and Lights, are a stunning natural light displays caused by interactions between plasma in Earth’s magnetosphere and charged particles from the Sun. These particles, primarily electrons and protons, travel toward Earth in the solar wind. When they reach our planet’s magnetic field, they are funneled towards the poles. As these high-energy particles collide with gases in Earth’s atmosphere (like oxygen and nitrogen), the atoms get excited (rise to higher energy levels) and release energy (fall back to lower energy levels) in the form of light, creating the vibrant colors we see in aurorae.

A very similar phenomenon causes emission nebulae to glow. In planetary nebulae for instance the huge flux of high energy particles from the remnant white dwarf at the center igntet the surrounding gases to glow.

And what a wondrous and spectacular phenomenon this is. It is truly and literally an out of world experience. Oh and whatever you do. remember not to fly into a plasma storm!

iPhone image of the Northern Lights, Oct. 10, 2024, Sudbury, MA (c) DEWolf 2024

Figure 1 -Comet P144Kushida – Seestar 50 s First Light 11 th mag. Feb. 19, 2024

I do have just a bit more to say about comets. Comets in the telescope, when they are distant, are little fuzzies. Figure 1  of Comet P144 Kushida, taken with my Seestar 50s ( a fifteen minute ( 80 frame stack) is not so exciting. It was one of my first light photographs with that telescope. At the time, I considered it to be a tour de force – a little fuzzy blob at 11th apparent magnitude.

It is illustrative of an important point about object brightness in astrophotography. When you’re talking apparent magnitude for points of light like stars things are pretty clear. And I’ve seen Seestar 50s images of Pluto, which usually comes in at mag 12 to 15. But for little fuzzies it’s more complicated.

In general, apparent magnitude is a scale used to measure the brightness of celestial objects as seen from Earth. The term “apparent” is important because it refers to how bright an object appears to an observer on our planet, not its actual luminosity. The scale is logarithmic, meaning each difference of 5 magnitudes corresponds to a factor of 100 in brightness.

For example, a star with an apparent magnitude of 1 is 100 times brighter than a star with an apparent magnitude of 6. The lower the number, the brighter the object. Some of the brightest objects in the sky, like the Sun, have a negative apparent magnitude, with the Sun’s magnitude being about -26.7.

For fuzzy objects, comets, galaxies, nebulae the apparent magnitude is an integration of all of the light as if it were focused down to a point. Think of the Andromeda Galaxy, Messier 31. At apparent magnitude 3.4 it appears quite bright to the naked eye. However, it is six moon diameters in angular size. If you were to focus all that light down to a starlike point it would be much brighter. Indeed, it would shine with magnitude 3.4.

So, not surprisingly, I do have a bit more to say about comets. On July 20, 1963, a very young David was with his father and telescope viewing a solar eclipse in Sullivan County, NY. My passion was ascending to the zenith of science geek-dom. In those days, I would have loved to photograph what I saw – especially the silent, cool, luminescent sights in the late evening or early morning twilight skies. It was time to dream. Fast forward many years to July of 2020, binoculars, telephoto, and tripod in hand I went out to attempt to find comet Neowise 2020 as it approached as if to kiss the Earth.

There were the expected problems. First, was finding it against the background light. Ultimately I could see it both in my binoculars and with the unaided naked eye. Second, was getting my tripod’s camera easy mount to lock in the dark. Third, sighting my camera on it was another story, since I couldn’t see it in the viewfinder. And fourth, there was the dreaded “M” or manual mode. I had preset everything, but my camera refused to shoot, and I finally realized that I needed to turn off the autofocus. So voila friends, here is Neowise, hovering gloriously over the Danvers or North River in Salem, MA. One of my first astrophotographs!

Despite the light pollution, perhaps because of it, this comet evoked all the magic and marvel of comets. There is the bright core and the nebulous and spectacular tail. And there is the sense of wonder and predilection. The David of 2020 thanked this beautiful comet on behalf of himself as well as the boy of 1963.

Discovered on March 27, 2020, by NASA’s NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) space telescope, the comet was originally a faint object on the outskirts of our solar system. But as it approached the Sun, it began to brighten, becoming visible to the naked eye. NEOWISE reached its closest point to the Sun on July 3, 2020, and its perihelion (closest approach) sparked a surge in its brightness, transforming it into one of the most spectacular comets to be seen in recent years. The comet sported two distinct tails: a dust tail that appeared white or yellowish, and a gas tail with a bluish hue, created by gases like carbon monoxide and water vapor. This beautiful double tail was best seen in the early morning or evening sky, just before sunrise or after sunset, making it a unique and fleeting sight.

The appearance of Comet NEOWISE was particularly notable because it was the brightest comet visible from the Northern Hemisphere in over two decades. Previous comets like Hale-Bopp in 1997 had captured similar attention, but NEOWISE’s beauty, combined with its accessibility to amateur astronomers and casual observers, created a sense of wonder and excitement. And I would argue it was the first comet of the digital photography age. People around the world, from backyard stargazers to professional astronomers, took to social media, sharing photos of the comet’s dramatic passage across the sky.

By mid-August 2020, Comet NEOWISE had passed beyond the Earth’s view, moving away from the Sun and fading into the depths of space.And truly this is what comets do. They appear out of the inky darkness of space, wax to a splendid fiery glory, and then fade into the void again.

Many, like Neowise 2020 will return again. Neowise 2020 is predicted to return again in 8820. Comets are like great trees in this respect. We plant them as an act of faith in and as a gift to the future.

The NSF Rubin Observatory Credit: Rubin Observatory/NOIRLab/NSF/AURA/P. Horálek (Institute of Physics in Opava) government photograph in the public domain.

Comets are deeply mysterious and have sought since antiquity. The earliest written records of comets date back to ancient Babylon, around 500 BC, and many cultures interpreted these celestial phenomena as omens or messages from the gods. However, it wasn’t until the 16th century that the scientific study of comets began to truly take shape.

In 1531, the German astronomer Michael Maestlin documented the return of a comet, marking one of the first instances where an astronomer connected a comet’s periodic nature with the idea that it was an object in orbit around the Sun. Later, in 1682, the famous English astronomer Edmond Halley observed that a comet which had appeared in 1607 and 1682 was the same object, suggesting comets had elliptical orbits. Halley’s Comet, helped establish the idea that comets were not random in their appearance but part of our solar system’s clockwork mechanism.

The first comet discovered through a telescope was in 1618, when Johannes Kepler used his observations of the night sky to note the presence of a comet near the constellation of Andromeda. The 19th and early 20th centuries saw an expansion of observatories and technological advancements in telescopes. The invention of photographic plates in the late 1800s allowed astronomers to capture images of the night sky with far more detail than ever before. As a result, astronomers could begin scanning vast sections of the sky in search of moving objects that could be comets.

In the 20th century, the rise of professional comet hunting truly took off with large telescopes, and the introduction of wide-field surveys helped make discoveries more routine. Observatories like the Mount Wilson Observatory in California, the Palomar Observatory, and the Mauna Kea Observatory in Hawaii became central to the discovery of new comets, some of which became famous in their own right, such as Comet Hale-Bopp (1995) and Comet NEOWISE (2020).

Today, many of the world’s most powerful telescopes are still in use for comet hunting. These observatories often employ both optical and infrared technologies to scan the night sky for signs of a comet’s unique characteristics: a bright core (nucleus) and a long tail.

Some of the most notable modern observatories include:

• The Pan-STARRS (Panoramic Survey Telescope and Rapid Response System): Located in Hawaii, Pan-STARRS is known for its wide-field sky surveys. This observatory has discovered hundreds of asteroids and comets, often catching those that could potentially impact Earth.
• The Sloan Digital Sky Survey (SDSS): Using the Apache Point Observatory in New Mexico, SDSS has mapped a vast portion of the sky, leading to the discovery of several comets, as well as asteroids, galaxies, and other astronomical phenomena.
• The Catalina Sky Survey: Based in Arizona, this project focuses on detecting near-Earth objects (NEOs), including comets. It is part of the search for hazardous asteroids and comets that could pose a threat to Earth.
• The European Southern Observatory (ESO): Operating several telescopes across Chile, the ESO is instrumental in comet research, providing valuable data to both professional and amateur astronomers.

If you look in a modern comet observing guide, such as Sky Safari, you will often see the names of these observatories and widefield comet scans attached to some of the major and most dramatic modern comets. This includes the comet that we have been talking about C/2023 Tsuchinshan Atlas A3. What’s in a name. Tsuchinshan: This part of the name is derived from the Tsuchinshan Observatory, which is located in China. Atlas: This part refers to the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey, which is an automated system that scans the sky for asteroids and comets, especially those that could potentially impact Earth.  A3: This part of the name is used to indicate the sequence of the comet’s discovery within that particular year. In this case, A3 signifies that this is the third comet discovered in 2023 that has been assigned a name in the “A” group. The “A” typically represents the first half of the year.

However, as I write there is a major game changer in comet, and asteroid, and novae  on the horizon [sic]. Coming on line this year is the launch of  Vera C. Rubin Observatory in Chile’s Atacama Desert. It will feature  a 8.4-meter telescope. If like me, you grew up when the 200 inch telescope at Palomar was king, pause a moment and recognize that that is ~328 inches.  The telescope is equipped with a state-of-the-art camera with a field of view larger than that of any previous sky survey telescope. It can capture the entire sky continuously every three nights looking for the telltale changes due to asteroids, comets, and novae. The observatory’s primary mission is to conduct the Legacy Survey of Space and Time (LSST), a 10-year project that will scan the entire sky repeatedly, providing a treasure trove of data on asteroids, comets, and other celestial objects.

The camera at the Vera Rubin Observatory has an extremely wide field of view that spans about 9.6 square degrees (that’s ~ twenty moon diameters). Its 3.2 gigapixel detector, will be the largest digital camera in the world. All of this boils down to a spatial resolution of about 0.2 arcseconds per pixel.

It once was true that revolution was rare, particularly scientific revolution. Now as we aspire to the singularity they are ever more familiar. Ten years from now we will speak very differently about the solar system and the universe. Vera Rubin will enable us to lift up a thousand veils and extend relentlessly the margins of the known universe.

I am part of all that I have met;
Yet all experience is an arch wherethrough
Gleams that untraveled world, whose margin fades
For ever and for ever when I move.

Ulysses

Alfred, Lord Tennyson

Figure 1 – Comet C/2023 A3 – Tusuchinshan Atlas from Spy Pond in Arlington, MA, ISO 800, 1 sec F/4 70 – 200 mm Zoom on October 12, 2024. (c) DE Wolf 2024

When I was teenage Davy and obsessed with astronomy I dreamt with wonder at the coming of Comet Halley in 1986. I was to be an impossibly old man at that date, although not as old as I would be at the coming of the millennium. I waited and many things happened. Finally, one night I went out to find the great comet. I searched the sky, star map in hand, with my father’s binoculars. I remember the moment vividly.

“So the years spin by and now the boy is twenty
Though his dreams have lost some grandeur coming true
There’ll be new dreams maybe better dreams and plenty
Before the last revolving year is through.“

The Circle Game, Joni Mitchell

The 1986 appearance of Comet Halley, compared to it predecessors, was kind of a dud. And we were left to new dreams, since none of us would live to see Halley come again.

“Comets are like cats: they have tails, and they do precisely what they want.”

David H. Levy

Fortunately, there have been other comets, which have lived up to the dream and mystery. In 2024, we were graced this fall with the appearance of Comet C2023 3A Tusuchinshan-Atlas – so wonderful! TC and I went out to Spy Pond in Arlington, MA. She wisely waited in the car listening to Bach, while I stood with a small crowd of nerdy Cambridge people waiting and stared in the chilly, setting light at the brilliance of Venus hovering above the horizon. Then we say it!

For comets in twilight, where the goal is to capture as much of the tail as possible I like to set up my Canon T6 with my 70 to 200 mm zoom on a tripod and take a wide open shot at something like 10 seconds. Figure 1 is the result, a spectacular comet against a cream blue sky.

Truly this comet was not a disappointment.  Comets have captivated humanity for millennia, inspiring awe and curiosity. These icy visitors from the far reaches of the solar system have been the subject of myths, legends, and scientific studies alike. They have been seen as harbingers of change, foretelling great battles won and lost.

“When beggars die, there are no comets seen: the heavens themselves blaze forth the death of princes.”

William Shakespeare

To the Elizabethans, who believed that the world was meant to be static the sudden appearance of these hairy mysteries could be terrifying.

As Hamlet says, “Time is out of joint. Oh cursed spite, that ever I was born to set it right.”

At their core, comets are icy bodies that orbit the Sun. They are composed primarily of frozen water, gases, and dust. Unlike planets or asteroids, comets have highly elliptical (elongated) orbits, which means they spend much of their time far from the Sun before making a dramatic, close approach.

When a comet gets near the Sun, the heat causes its ices to sublimate (change directly from solid to gas), releasing gas and dust into space. This process creates a glowing coma (a cloud of gas and dust) and often a bright, visible tail that points away from the Sun.

Comet tails, in fact, come in three distinct types, each created by different interactions between the comet, the solar wind, and the Sun.

Dust Tail:
This is the most visible and often the brightest tail. The dust tail forms from small, solid particles (mostly dust) that are released as the comet’s icy nucleus heats up and begins to sublimate as it gets closer to the Sun. These particles are pushed away from the Sun by the pressure of sunlight. The dust tail tends to be broad and curved, following the comet’s orbit.

Ion Tail (Plasma Tail):
The ion tail is created when the comet’s gases (mostly water vapor, carbon dioxide, and other compounds) ionize due to the intense ultraviolet radiation from the Sun. The solar wind then carries these charged particles away from the comet, forming a tail that always points directly away from the Sun. The ion tail is often faint and blue due to the ionized gas, and it’s more straight compared to the dust tail.

Antitail:
This one is a bit more unusual. An antitail occurs when the comet’s orbit is such that, from our perspective on Earth, the ion tail appears to point in the opposite direction to the Sun. This phenomenon can happen when the comet is moving away from the Sun and the ion tail is still pushed by the solar wind. The antitail appears as a faint feature, and it’s not visible in all comets. But it was brilliantly visible with comet C/2023 3A.

Comets are believed to be leftovers from the early solar system. They are said to be “cosmic time capsules,”  When our Sun and planets formed about 4.6 billion years ago, the outer regions of the solar system were home to many icy bodies that never coalesced into planets or moons. These icy bodies, known as cometary nuclei, contain some of the most primitive material in the solar system and are thought to have been preserved in their original state since the formation of the solar system.

There are two main regions in the solar system where comets originate: The Kuiper Belt: Located just beyond Neptune, the Kuiper Belt is home to short-period comets, which have orbits that last less than 200 years. These comets come from a relatively stable region and are believed to be remnants from the solar system’s early years. The Oort Cloud: A much more distant and hypothetical region, the Oort Cloud is thought to be a vast sphere of icy bodies that could contain long-period comets (those that take more than 200 years to orbit the Sun). These comets are often sent into the inner solar system by gravitational interactions with nearby stars.

These are just some basic facts about comets. Along with asteroids, they are very ancient objects which present in an unspoiled way the very beginnings of our solar system four plus billion years ago, We can visit them now, and in so doing sample our very own origins. Always there is the wonderful dichotomy between the physics of comets and the metaphysics of wonder at these cosmic voyagers some visiting us over and over again with clocklike regularity; others fleetingly passing us but once.

“Old men and comets have been reverenced for the same reason: their long beards, and pretences to foretell events.”

Jonathan Swift