I keep notes on what I do with my telescopes! For the last two months I have been trying to collimate my Nexstar 8 SE. Collimating a Schmidt Cassegrain telescope is not easy, but also not overwhelmingly difficult. On May 7th I did a proper laser alignment and have been waiting for clear skies to finalize it with a star collimation, and waiting, and waiting … I’ve had rain and more rain and when it wasn’t raining dense clouds. Dinah is forlorn.
My prophet-apps finally predicted four clear sky nights in a row this week. The first was last night and what did I get – Canadian wild fire smoke!!! Can’t we get rid of it with a tariff or something?
I’ve had nothing to do but think about this. The big issue is what your minimum or limiting magnitude is, the dimmest star you can see. The first point is the aforementioned Bortle number. Bortle, as we discussed, is a measure of light pollution. I am working under Bortle 5.7 skies and I asked Chat GPT to give me a plot (Figure 2) of limiting magnitude vs Bortle number.
Figure 2 – Limiting Magnitude vs. Bortle Number
So on a perfectly transparent night, my limiting magnitude should be about 5.2.
Now the other factor to consider is the transparency. This is usually about 0.3 to 0.5 for my skies meaning there is a reduction of limiting magnitude by about 0.3 to 0.5. So last night it should have been and was predicted to be about 4.8, which seems about right to me. However, the faintest star I could see was Spica or Alpha Virginis at magnitude 1.0. Yikes!
Dinah, who comes from literature herself, paraphrases Alexander Pope from his Essay on Cats, “Hope springs eternal in the feline breast, cat never is but always to be blessed.”
Figure 1 – The Andromeda Galaxy, Messier 31 and her companion galaxy Messier 33 22 min Image taken with SeeStar 50s and shows the difficult in encompassing such a large object without tiling. (c) DE Wolf 2024
The classic approach to amateur astronomy was to get a decent telescope and examine the various wonders of the celestial spheres. The operative word was “slowly.” Disappointingly, except for the moon and the planets, these wonders were all little, medium and big fuzzies! This has been changing with the revolution in smart telescopes, where you can integrate the image from these fuzzies with time to reveal not only structure but color.
It is not surprising however, thst eighteenth and nineteenth century astronomers mistook many of the deep-sky objects, galaxies, and nebulae, for comets. As a result, there was increasing need for catalogues of these deep-sky fuzzies. These catalogues each have an identifying acronym, seemingly designed (?) to confuse the neophyte.
The most famous early compilation of deep sky objects is the Messier Catalogue, the M numbers, named after French astronomer, Charles Messier. Ultimately, Messier created a list of over 100 such objects, published in 1774.
Messier’s catalogue included objects like:
M1 (The Crab Nebula) – the remnant of a supernova explosion.
M31 (The Andromeda Galaxy) – a massive spiral galaxy and our closest galactic neighbor.
M42 (The Orion Nebula) – a stellar nursery.
As telescopes improved, the limits of Messier’s list quickly became apparent, and in the late 19th century, John Louis Emil Dreyer, a Danish-Irish astronomer, compiled the New General Catalogue (NGC) of over 7,800 objects, which was published in 1888 and became the new standard for deep sky observation.
After publishing the New General Catalogue (NGC) in 1888, John Louis Emil Dreyer continued to compile observations from both professional astronomers and improved telescopes. The result was two supplementary volumes known as the Index Catalogue (IC):
Together, the NGC and IC form one of the largest and most enduring astronomical cataloguing efforts, standing the test of time through continued validation and cross-referencing in modern sky survey.
In 1995, renowned British astronomer and popularizer, Sir Patrick Moore, introduced the Caldwell Catalogue, a supplement to the Messier list designed to help amateur astronomers. Unlike Messier’s list, the Caldwell Catalogue intentionally included both Southern Hemisphere objects (e.g., the Omega Centauri globular cluster). and brighter, visually stunning objects that Messier missed. The Caldwell Catalogue contains 109 entries, each labeled C1 to C109, chosen for their observational value through small to mid-size telescopes.
There are several other catalogues that you might come across. These include:
Sharpless Catalogue – A list of H II regions (emission nebulae).
Herschel 400 – A list based on observations by William and Caroline Herschel, chosen for more advanced amateurs.
Abell Catalogue – A collection of galaxy clusters used in extragalactic astronomy.
Needless-to-say, we are now progressively in an age of digital star surveys such as the Sloan Digital Sky Survey (SDSS) and missions like Gaia. We can expect the Vera Ellen Observatory to increase our catalogue of the skies exponentially. This is, after all, the era of big data. Today’s astronomers can access online open databases like SIMBAD, VizieR, and tools like Aladin Sky Atlas.
Figure 2 – Dinah plans a night of observing using the Astronomeow.
Artificial Intelligence is a kind of dominant feature in the Hati and Skoll “From the Observacar” blog. In a recent blog, I introduced the astro-loving kitten Dinah. Dinah was, of course, Alice in Wonderland’s cat, perhaps not a real cat, but then neither was Alice real. She is such a delightful feline spirit that I asked Chat GPT for a drawing of Dinah as a kind of mascot for the blog, and here she is making her debut in Figure 1. More importantly I asked her (ChatGPT) how to preserve Dinah’s essence for future images. This is certainly the stuff that StarTrek is made of. So, apparently I have a rather unpopular opinion concerning M’Benga keeping his daughter in the transporter, until he can find a cure for her. Every single Trek fan that I’ve talked to that’s seen SNW COMPLETELY disagrees with me, saying it’s unethical to let him keep her in the transporter so her illness doesn’t get worse. But I should point out that ChatGPT and her kin have made our own a strange new world, and I think that we had better tame it, since we are never going to control it. Dinah, at least, is completely tameable!
Dinah loves all things astronomical, both historical and fictional, but especially equipment! For her debut, she has asked me to repost my astrophotograph of the Cat’s Paw Nebula (NGC 6334). It is from my black and white period, 2021 to be specific.
Figure 2 – NGC 6334, the Cat’s Paw Nebula. (c) DE Wolf 2021.
This image was taken with one of the Skygems Southern Skies remote telescopes, the Hakos Veloce 200 RH remote telescope in the Namibian desert. It is a stack of six 600 sec exposures. NGC 6334 is truly the anvil of the gods. It is a stellar nursery. Stars are literally being formed before your eyes. Well, in general, the time scale is a bit slow. It lies in the constellation Scorpius and was discovered by astronomer John Herschel in 1837. Herschel observed it from the Cape of Good Hope in South Africa. So pretty close!
NGC 6334 is located about 5,500 light-years away from Earth. The Cat’s Paw Nebula spans roughly 50 light-years across. It’s classified as an emission nebula, meaning it’s composed of clouds of ionized gas that emit light of various colors. The vivid red glow that dominates most images of NGC 6334 comes from hydrogen gas excited by the intense ultraviolet radiation from newborn stars within. Here we see none of this, since the image is in the glorious black and white of my youth.
Astronomers believe the nebula contains tens of thousands of young stars in various stages of development, many of them deeply embedded in the thick interstellar dust and thus invisible in optical wavelengths. That’s where infrared telescopes like those on board the Spitzer Space Telescope or the European Southern Observatory’s VISTA telescope come into play—revealing the hidden stellar nurseries within.
What makes NGC 6334 particularly fascinating is its star-forming activity. The nebula is estimated to have birthed stars as massive as 10 times the mass of the Sun—some only a few million years old, which is considered very young in cosmic terms.
Regions like the Cat’s Paw give astronomers a closer look at the mechanisms behind stellar evolution. By studying this nebula, scientists can better understand how massive stars form, how they influence their environments, and how stellar winds and radiation sculpt the surrounding gas into new star-forming knots and filaments. The “toes” of the nebula—bright, bubble-like lobes—are actually sites of intense star formation, glowing brightly due to the heat and energy of the new stars within.
Although it’s most widely known as the Cat’s Paw Nebula, NGC 6334 is sometimes referred to as the Bear Claw Nebula, depending on how its lobes are interpreted in images. No friends of Dinah’s are allowed to think this! She believes such misnomers represent the work of an ailurophobic cabal!
Dinah would also like me to add that the Cat’s Paw Nebula is only one of many celestial objects whose names honor cats. These include the Cat’s Eye Nebula (NGC 6543), Leo, Leo Minor, Lynx, the Cheshire Cat Galaxies (yes, I know more Alice), and the now vanished Felis.
Readers of “From the Observacar” are left to ponder whether there is any relationship between the Owl Planetary Nebula (of our previous blog) and the Cat’s Eye Planetary Nebula and this:
“The Owl and the Pussy Cat went to sea In a beautiful pea-green boat, They took some honey, and plenty of money Wrapped up in a five-pound note. The Owl looked up to the stars above, And sang to a small guitar, “O lovely Pussy, O Pussy, my love, What a beautiful Pussy you are, You are, You are! What a beautiful Pussy you are!”
Pussy said to the Owl, “You elegant fowl! How charmingly sweet you sing! O let us be married! too long we have tarried: But what shall we do for a ring?” They sailed away, for a year and a day, To the land where the Bong-tree grows And there in a wood a Piggy-wig stood With a ring at the end of his nose, His nose, His nose, With a ring at the end of his nose.
“Dear Pig, are you willing to sell for one shilling Your ring?” Said the Piggy, “I will.” So they took it away, and were married next day By the Turkey who lives on the hill. They dined on mince, and slices of quince, Which they ate with a runcible spoon; And hand in hand, on the edge of the sand, They danced by the light of the moon, The moon, The moon, They danced by the light of the moon.“
Messier 97 the Owl’s Head Nebula, Celestron Origen ~ 20 min exposure (c) DE Wolf 2025
Among the most hauntingly beautiful of the night sky’s cosmic clouds is the Owl Nebula, officially known as Messier 97 (M97). It is located about 2,030 light-years away in the constellation Ursa Major. This celestial wonder offers a glimpse into the future of stars like our Sun—and looks remarkably like a ghostly pair of eyes staring back at us.
Discovered by Pierre Méchain in 1781 and cataloged by Charles Messier shortly after, M97 earned its nickname thanks to its peculiar appearance. Through a telescope, especially in photographs with long exposures, the nebula reveals two dark, circular patches that resemble the eyes of an owl. These “eyes” are actually regions of lower gas density in the otherwise round shell of glowing gas. It’s a poetic name for an object that looks like a silent sentinel perched in space. In contrast, the Owl’s Head Cluster (NGC 497) stares back at us with a pair of bright stellar eyes.
The Owl Nebula is a planetary nebula, which—despite the name—has nothing to do with planets. The term was coined in the 18th century when such objects appeared planet-like through early telescopes. In reality, planetary nebulae are the remnants of dying stars.
The story of M97 began when aSun-like star exhausted its nuclear fuel. As it ran out of hydrogen and helium to burn, it expanded into a red giant, shedding its outer layers into space. The hot, exposed core left behind emits ultraviolet radiation, lighting up the surrounding gas and creating the colorful glow we see today.
At the heart of the Owl Nebula lies this dying star’s white dwarf core—a dense, Earth-sized stellar remnant that will slowly cool over billions of years. This white dwarf core emits huge amounts of X-ray and Cosmic energy radiation. This radiation excites the gaseous cloud that surrounds the core, causing colorful fluorescence, much like the aurora borealis. M97 typically exhibits a blueish color with patches of red. Long-exposure images, such as the twenty minutes here, bring out shades of blue-green and red, caused by ionized oxygen and hydrogen.
While not the brightest nebula in the sky, M97 is one of the more complex. It has an almost spherical shape with subtle variations in brightness and gas density. Astronomers believe it is between 6,000 and 8,000 years old, and its structure has helped researchers better understand the late stages of stellar evolution.
The Owl Nebula is more than a striking image—it’s a window into the lifecycle of stars and a reminder that even in death, stars can leave behind beauty and mystery. It’s a cosmic memento mori, gazing back at us from across the galaxy, reminding us that everything—even stars—must eventually change.
Figure 1 – Messier 104 the Sombrero Nebula, Celestron Origin Image (c) DE Wolf 2025
Attempts to recollimate my Nexstar 8 SE have been a nightmare – more on that when the problem is solved. So, rather than wasting all the clear nights I decided last week to spend a beautiful clear-sky session with my Celestron Origin 8 SE. Even then, I ran into problems, due to clouds drifting into the field of view and crashing the acquisition. Nevertheless, Figure 1 is an approximately 20 min image of Messier 104, the Sombrero Galaxy – named, I think for obvious reasons.
Messier 104 is like a glowing hat floating in space. It’s located about 31 million light-years away in the constellation Virgo. Not that I ever took my own astrophotograph of it back then. But, it was certainly a time for youthful favorites and M104 was clearly one of these. and it’s one of those deep-sky objects that just sticks with you once you’ve seen it.
When viewed through a telescope, M104 looks like a broad, flat disk with a bright central bulge—and a dark dust lane cutting across it. That dust lane gives it the appearance of a Mexican sombrero, especially when viewed edge-on. Note the “boiling” of this edge. I think with a significantly longer exposure great detail can be obtained with the Origin and now that is one of my summer observing goals.
Even with a mid-sized telescope, you can catch that shape under decent sky conditions. It appears as a bright core with a dark line running through it—a visual treat that makes it a favorite among amateur astronomers.
Technically, it is an unbarred spiral galaxy (SA(s)a), about 50,000 light-years across. That is half the size of our Milky Way. It has an apparent magnitude a round 8.0, making it just beyond naked-eye visibility. It has a central black hole: Estimated at 1 billion solar masses! That’s enormous, even for a galaxy this size.
A great mystery centers around M104’s huge central bulge. What is causing this? The bulge is made up mostly of older, red stars — similar to what we see in elliptical galaxies. This suggests the bulge formed early in the galaxy’s history, possibly through rapid star formation or a series of mergers with smaller galaxies. These events would have funneled gas into the center, creating a dense, star-rich core.
As a result some astronomers believe M104 might be a hybrid between a spiral and an elliptical galaxy. Its large bulge hints at a past merger—perhaps it collided with or absorbed a smaller elliptical galaxy long ago. These kinds of interactions can puff up the central region and leave behind a thick, spherical structure.
M104 hosts a supermassive black hole that’s a billion times the mass of the Sun—one of the most massive known in a galaxy of this size. Its gravitational influence likely helped shape and maintain the dense bulge around it, pulling in stars and gas over time.
Additionally there is low star formation in the bulge. Unlike the disk (where you find spiral arms and lots of young, blue stars), the bulge is quieter. It’s dominated by older stars and has relatively little gas and dust, which means fewer new stars are forming. This makes the bulge appear more pronounced, especially when viewed edge-on like in M104.
It is the bulge, of course, that intrigues us most about Messier 104. Back in the day when I was newbie amateur astronomer, it was one of my favorite deep-sky objects. This was way before I ever saw it myself let alone photographed it. That was in the day of tedious star-hopping, no computers, and strictly unguided alt-azimuth mounts. It reminds me that about a month ago I watched a wonderful an ancient BBC production of the Shakespeare’s The Tempest. Newly aware of a world filled with people, Miranda says:
“Oh what a brave new world this is that has such people in it!”
It is, I think, a poetic irony that it is AI, a kind of non-being person that is leading us into such a brave new world. And again, we are led to Hamlet’s assertion that “There are more things in heaven and Earth, Horatio, than are dreamt of in your philosophy.” Hamlet must deal with ghost-like ethereal spectres, while Miranda’s ghosts are more corporeal.
I suppose that I really should end here with a quote from Aldous Huxley’s novel “Brave New World.”
“Facts do not cease to exist because they are ignored.”
Figure 1 – Gravitational lensing as imaged by the Hubble Space Telescope and in the public domain because it was taken by a government agency, NASA. Here a Luminous Red Galaxy is lensing the light from a blue galaxy behind it.
Apologies for disappearing. I have been visiting Bortle 4.7 skies! But I did want to pick up where we left off about reference frames and explore how this connects with Alice and the Rabbit hole.
Remember being on a train and not being able to figure out whether the train or the station is moving. This is the case of trains with constant speed or velocity. That is nothing is accelerating, and such is the realm of what is referred to as special relativity. We, well Einstein actually, recognized, perhaps intuitively, that there is no absolute rest frame which doesn’t move compared to all other possible reference frames. For this to be so, it must be that the laws of physics are the same in all reference frames. One particular law was outstanding, the law for propagating an electromagnetic wave. Fundamental to that law is the fact, verified by the famous Michaelson and Morley Experiment. that the speed of light must be the same in all reference frames. This conclusion leads to some mighty strange or counter-intuitive things;
If you measure a distance in one frame, you get a different distance in another – so called Lorentz contraction.
If you measure a time interval in one frame, it is different in another – the so called twin paradox.
If two events are simultaneous in one frame, they may not be simultaneous in another.
As strange as these may seem they have none-the-less been demonstrated experimentally! As Hamlet famously said, “There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.” These are the ghosts that we must deal with.
Well. I kind of meant to recount not further confound. So just remember that in a world where trains move at different speeds, if you measure the speed of light it will always be the same namely 299,792,458 m/sec if you’re measuring in a vacuum. “I try to be precise, Captain,” said Mr. Spock. Physicists like Vulcans are pesky about being precise.
Moving on! We were told as undergraduates that the situation, where reference frames are accelerating relative to each other, is hard conceptually. Well, really not so! And here is where we return to Alice. Alice falling down the rabbit hole is reminiscent of a overwrought trope in relativity theory, namely of you or often a little Einstein figure inside a rocket ship moving through space, or not, since everything is relative. So here’s Alice in the rocket ready to take off. When she was in Wonderland she had left her kitten Dinah at home but worried whether she was being properly cared for. So this time Dinah is with her in the rocket. Alice perhaps maliciously, but definitely as a true Victorian experimentalist, keeps dropping Dinah upside down pondering the issue of why she always lands on her feet. But that part is a different story. The important point here is that Dinah keeps accelerating towards the floor at 9.8 m/sec squared under gravity. Alice yawns widely, ignoring the fact that it is impolite for Victorian ladies to yawn without covering their mouths. Bored she looks out the window and is surprised to discover that she is no longer on the launch pad but accelerating through space at 9.8 m/sec squared. Well, this certainly puts a different light on it!
This experiment with poor little Dinah, who has now gone off hunting for mice, illustrates an important point. Everything is relative! You nor Alice can distinguish between being at rest on the Earth and subject to a gravitational force with acceleration 9.8 m/sec squared in a rocket moving through space and subject to inertia at 9.8 m/sec squared.
Now here’s the important point or pointer. Alice pulls out of her pocket her handy-dandy, anachronistic, laser pointer and fires it at the opposite wall of the rocket. Since the rocket is accelerating upwards through space at 9.8 m/sec squared the light beam hits the wall along a ballistic path slightly lower than the point on the wall directly across from Alice. Remember that light is moving at a finite speed of 299,792,458 m/sec. No biggie there. But remember that Alice can’t really distinguish between acceleration due to inertia of gravity. All is relative and it becomes a matter of point of view. Soooooo it must be that despite the fact that photons or light particles have no mass that they are bent by gravity. Wow, that is really the fundamental conclusion of general relativity.
This bending of light was triumphantly demonstrated by Arthur Eddington, Frank Watson Dyson, and their collaborators during the total solar eclipse on May 29, 1919. The Sun measurably bent the light path of stars behind it. Indeed, if a star is behind the Sun it can be bent by the Sun’s gravitational force to produce multiple images of the star in front of the sun during an eclipse. Reading about this as an undergraduate I was in awe.
But now we have something more amazing, images from the Hubble Space Telescope and now the Jack Webb Space Telescope. Figure 1 shows one of the best and most impressive of these. Here a Luminous Red Galaxy is lensing the light from a blue galaxy behind it. Here the alignment of the two galaxies is so perfect that a so-called Einstein’s Ring rather than a set of multi image points is produced.
Dinah has now tired of hunting and is curled up on Alice’s lap giving herself a bath and pondering whether an observer outside the rocket would really know if she was alive or dead.
Figure 1 – NGC 7293 the Helix Nebula, SeeStar 30 min Image (c) DE Wolf 2024.
I wanted to talk a bit about relativity. You know what they say. “It’s all relative.” It has nothing to do with uncles, and cousins, and aunts. It has to do with the fundamental nature of the universe and the dominant force, when our perspective gets big, namely the force of gravity.
But let’s start with so-called reference frames, and this ultimately connects with Alice in the rabbit hole again – but I get ahead of myself. So let’s begin by imagining that its a sunny day in 1898 and you are sitting in London’s Piccadilly Station waiting for your train to depart the station. You are in the train, and it is motionless. As a Victorian you tend to be pretty confident in your assertions and beliefs. Suddenly you see and feel the station move backwards or perhaps better the train sitting next to yours, but then you realize that this is not the case. Actually, you are moving forward. Well that’s a relief. I mean how could that station be moving?
What is so disconcerting about the station moving? It is because we believe that stations are too massive to move. Hmm! Isn’t the station on the Earth rotating at about 1,670 km per hour? It’s time to grow up people and use the metric system! And isn’t the Earth revolving around the Sun at about 30 km per second? Yikes? And isn’t the Sun and Earth revolving around our Milky Way galaxy at about 200 km per second? Double yikes? And it goes on from there. The station and the Earth and the Sun are certainly moving and moving incredibly fast!
I will avoid mathematics here, but the thing is that to you, sitting in the train, from your perspective the station is moving. That is until you reject that conclusion on a faulty logic basis. From the perspective of someone on the train platform or on the neighboring train you and your train are moving. These perspectives are what are referred to as frames of reference.
Who is really moving? Which frame of reference is actually at rest? We don’t know. It’s all relative! I’d like to say that Einstein invented this concept. But he didn’t. It goes way back. Hence we have for instance Galilean (the Leaning Tower of Pisa guy) reference frames. We have a strong and prejudiced belief that there is an ultimate rest reference frame. There is not. It is all relative.
In Einstein’s view things do however get more interesting. Imagine that you see a little child in the front of the train and you throw a ball to him with a speed v. That’s how you see it at “rest” in your trains. What does a person at “rest” on the platform see? They see the ball move through space with the added speed of the train, call that V. So they see the ball moving at speed v+V. Pretty straight forward! That’s what’s referred to as a Galilean transformation. But the problem is that it was shown at the beginning of the twentieth century that the same is not true with light. If you shine a flashlight at the child it advances at the speed of light c. Same is true for what is measured by the person on the platform not V+c but just c. WTF?
This was Einstein’s great contribution and lies in the statement that it is all relative, that there is no preferred reference frame. If there is no preferred reference frame then the laws of physics must be the same in all reference frames. Suppose you have a laboratory and are at “rest” doing physical experiments. The laws of physics apply both in the laboratory and as seen by an observer, who thinks of himself at “rest” either walking past the laboratory or walking around it. Put that way the inviolability of the laws of physics is both intuitive and obvious.
But at the end of the nineteenth century the great achievement of physics was the unification of the theories of electricity and magnetism and optics. Those laws must be the same in all reference frames too. You might have on the train a small antenna with a current moving up and down. This generates an electromagnetic wave. And the velocity of that wave is the speed of light. But since no reference frame is preferred, there is no absolute rest reference frame, the wave as seen from the platform must have the same speed c. Wow! This as we shall see has enormous potential.
I hope that I have not given you a headache! And I think for our efforts we deserve a nice astrophotograph taken by yours truly on August 13, 2024 of the Helix Nebula NGC 7213 with my Seestar 50s. This image of a glorious planetary nebula is one of my best Seestar images and shows just what this little telescope is capable of. This last sentence is in honor of the cocky Victorians who believed that prepositions were not words to end sentences with. Such is not the case!
Figure 1 – Centaurus A taken in black and white at the iTelescope.net Sliding Spring Observatory in Australia. (c) DE WOLF 2024.
One of the cool facts about the Observacar is that you can drive it in your minds eye to Australia and Chile and image all sorts of southern sky celestial objects using the itelescope network. One of the most intriguing of these is Centaurus A. In the vastness of the universe, there are a few objects that capture the imagination of astronomers and space enthusiasts alike.
Centaurus A is also known as NGC 5128. It is located approximately 13 million light-years away in the Centaurus constellation. Despite this seemingly gigantic distance, Centaurus A is in fact our closest active galactic nucleus. It is classified as an elliptical galaxy, but with a twist: it also has a distinct dust lane that cuts through its center at an angle, giving it a unique appearance.
Centaurus A contains an estimated 100 billion stars, but what makes it particularly unique is its combination of a massive elliptical galaxy and an active core, all wrapped up in a dusty, star-forming region. The dust lane visible in images gives the galaxy a fascinating and almost ominous look when viewed through a telescope.
Perhaps needless-to-say, its core contains a supermassive black hole. This black hole is incredibly powerful and actively feeds on surrounding gas and dust. The energy released from this endocytotic process (to borrow a term from biology) results in intense radiation, which is what makes Centaurus A such an enormous radio source.
As a result, Centaurus A’s core is extremely active and is spewing out huge jets of energy and matter in the forms of radio waves, X-rays, and optical light.These jets can extend for hundreds of thousands of light-years into space, which is enough to influence star formation and the environment in the surrounding galaxy.
The dark dust lane that bisects the galaxy is made of cold gas and dust, which is believed to be a remnant of an ancient collision with a smaller spiral galaxy. This galactic collision likely occurred several billion years ago, and it’s a key factor in the galaxy’s current shape and structure.
In fact, the formation of the dust lane suggests that Centaurus A underwent a galactic merger, a common phenomenon in the universe. When galaxies collide, they often merge to form a new and larger galaxy. These interactions also fuel the activity of the central black hole, which grows as it consumes more material from the surrounding environment.
Centaurus A is a favorite target for many of the world’s most advanced telescopes, including the Hubble Space Telescope, Chandra X-ray Observatory, and the Atacama Large Millimeter Array (ALMA). Each of these observatories has provided unique insights into the structure and behavior of the galaxy because they each observe in different spectral regions.
Figure 1 – Long-tailed ducks on the Merrimack, Newburyport, MA (c) DE Wolf 2025
The days are definitely getting milder, and all our thoughts are turning to spring. I have begun schlepping by big birding lens with me on my morning walks and have returned to the Great Meadows National Wildlife Refuge to watch the spring migration come in. It is mud season! The red-wings are creating a cacophony of their trumpet blasts. There are bald eagles, red-tailed hawks, mallards, wood ducks, and tree swallows. The ever present Canadian Geese seem to be focused on mating and are ignoring the tariff war.
Two weekends back, TC and I were watching the long-tailed ducks (Clangula hyemalis) float by on the Merrimack, contemplating a bit sadly the devastation that bird influenza is taking on our avian populations. We were eating sandwiches. They are fighting for their lives. It is as if the gulls have fallen silent.
The long-tailed duck (Clangula hyemalis) is one of the most distinctive and fascinating waterfowl species of cold northern waters of the world. With its unique appearance, remarkable behavior, and captivating migration patterns, the long-tailed ducks are truly eye-catching. Adult males, particularly during the winter, are known for their dramatic plumage. Their most iconic feature is, of course, the long, flowing tail feathers that extend far behind their body—hence the name “long-tailed” duck. These tail feathers are especially prominent during the breeding season, where they can measure up to 10 inches (25 cm) long, adding an elegant flair to their otherwise compact body.
Males are adorned with a mixture of black, white, and chestnut hues, paired with bright orange bills, making them easily recognizable. Females and younger ducks, on the other hand, have a more subdued, mottled brown plumage, which helps them blend into their surroundings.
Native to the northern hemisphere, long-tailed ducks breed in the Arctic regions of North America, Europe, and Asia. During the summer months, they can be found in remote areas of Canada, Alaska, and Siberia, where they build nests on the ground in tundra wetlands. These areas are cold, windy, and often surrounded by snow and ice, making them ideal for a species that thrives in such harsh conditions.
In winter, however, long-tailed ducks migrate south to more temperate regions, like Newburyport, often spending the colder months in the coastal waters of the North Atlantic, the North Pacific, and along the coasts of the northern United States. Some even make their way to the Mediterranean. So here we are catching them at the start of their northern migration. These are diving ducks. They can dive to 60 meters in search of food.
Figure 1 is a group that I photographed. It is not a world class bird image but has some features that I really like. First, it is very subdued color, almost black and white. Yet you can see the mahogany heads and red tipped bills of the males. Second, the birds are together but each doing its own things. They are like a blissful family The unison of swimming together is very subtle. They almost seem to ignore one another, one looking ahead, one side-wards, and one preening. But the fact is that at any moment one of the ducks will dive and rapidly all of the others will follow.
