Author Archives: David

From the Observacar – Centaurus A

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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.

Long-tailed ducks

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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.

Should I go out with my observacar?

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Figure 1 – Norman Rockwell – cover of the May 1, 1920 issue of The Saturday Evening Post, showing a Ouija board in use. Image in the public domain in the United States because of its age.

Today is March 27 and the last clear night that I had with my telescope was March 11 – getting rather annoying! Following up on my blog yesterday about the Bortle Scale, I’d like to ask today, how can one predict “Clear Skies?” I have used a number of proverbial apps to try to accomplish this.

The first was the ten day forecast from The Weather Channel with its hourly prediction. I find that it works pretty well, but doesn’t really give you the insight that you need at the level that you need it. I think the obvious reason is that they’re goal is not astronomical.

Next I tried SkyLive. This I found has beautiful graphics but wasn’t very useful for me,

Then I tried Astrospheric which actually was of quite reasonable usefulness.

Then I was driven to pay the reasonable price for GoodtoStargaze. This is my GOTO app and the one I recommend. I use it all the time, and augmented with The Weather Channel and sometimes Astrospheric, I find that I can usually do quite well at predicting the sky conditions. This is not to say that I have not had the experience of going out on a “clear” night only to be confronted with a mass of cumulus clouds. As a physicist I respect the fact that predicting massive weather systems with what I am told are unstable differential equations is iffy at best and you are easily off by ten miles or so.

Originally I would record the sunset or sunrise and moon conditions and leave it at that. Slowly my observing notebook is morphing into true scientific notebook, and as far as sky conditions beyond Bortle Number, I record a lot of parameters with the hope/plan of someday using my imaging successes and failures predictively. I may even create an AI app to scrape my notebooks for best conditions for what.

The parameters that I record are:

Sunset/sunrise – since you usually need at least 45 min into darkness befor you can align scopes
Moonrise – the moon is a major and variable source of light pollution
Moonset – when will this annoyance go away. TC is always saying to me, “Just look at how beautiful the full moon is tonight!” And I’m like, “eh……”
Moon Phase – note that percent lunar illumination is a bit different and you can use that instead
Temperature range – obvious point too cold, even with the observacar and I’m not going out
Windchill – this for the same reason
Dew point – is kind of a predictor when you need your lens heater
Relative Humidity – this for the same reason
Wind conditions – this comes in two flavors steady wind. I set a limit of about 25mph and gusts 30 mph. Don’t want my telescope falling over or vibrating too much for imaging
Cloud cover – I really like this below 25 %
Seeing – this is the discernable star resolution with the naked eye. As I’ve gotten older my naked eye has gotten more and more modest. But the basic point here is that the smaller this number is the finer detail you can see.
Transparency – this is a tough one but basically is the magnitude loss of a star going through the air mass of the atmosphere
Visibility – this is the usual how far you can see. I number of 10 miles or better is what you are looking for.
Light pollution – this is our favorite the old Bortle Number, which usually doesn’t change much day-to-day
Notes – whatever else you want to record.

Every entry in my observing notebook begins with these numbers.

A lot of times when my apps are predicting clear skies and cumulus clouds or worse rains abound, I start to wonder if there isn’t a device that would be at least as good at predicting sky conditions. Such a device is shown in Figure 1 and is called a Ouija Board!

An Observacar in a Bortle

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Figure 1 – The Bortle Scale Credit: ESO/P. Horálek, M. Wallner

Many things seem better in our remembrance of them. I used to observe with my 60 mm Unitron Refractor in NYC, doing everything wrong (like looking through my apartment window with my telescope). But, and in any event, I was always limited by the light pollution presented by the big city. But in summer I would go to “Upstate NY” and “wow” the skies were spectacular and the beauty of the Milky Way could bring one to tears. I’m a romantic.

Today we struggle in most places to catch a glimpse of the Milky Way. Indeed, in most places you stand no chance of seeing it. Light pollution is the bugaboo of amateur astronomy.

The Bortle Light Pollution Scale is a nine-level system used to measure the quality of the night sky based on light pollution. It was developed by John E. Bortle in 2001. This scale helps both casual observers and serious astronomers assess the level of light pollution in a particular location. It was designed to aid in comparing different locations and providing a better understanding of how much artificial light interferes with stargazing. You can chose a site based on it and putting the Bortle Number in your observing notes makes you feel really in the know, even though you have no control over it.

The scale is inverse, meaning the lower the number the better, Bortle 1 (Excellent Dark-Sky Site) to Bortle 9 (Inner-City Sky), with each class offering a description of what can be observed and the degree of light pollution in the area. It is akin to the magnitude scale, where smaller means brighter.

Breakdown of the Bortle Scale

Bortle 1 – Excellent Dark-Sky Site

  • This is the ideal environment for stargazing. Observers in this location will experience pristine, unpolluted skies with no significant artificial light. The Milky Way is visible in all its glory, and faint objects like galaxies and nebulae are easily observed with the naked eye. This is typically found in remote locations, far away from urban centers, where artificial lighting does not reach. I’ve read about shadows cast by the Milky Way in Sagittarius and Scorpius. I mean really? That’s just amazing!

Bortle 2 – Typical Rural Sky

  • Rural areas with very little light pollution fall under this class. The Milky Way is clearly visible, though some light pollution may slightly affect the sky. While bright stars are easy to spot, the faintest deep-sky objects might be harder to detect without a telescope. Still, it’s a good location for casual stargazing.

Bortle 3 – Rural/Suburban Transition

  • This is a more common location for many stargazers, found in the outskirts of rural and suburban areas. The Milky Way is still visible, but there is some light pollution that washes out fainter stars. The sky is noticeably brighter, and some constellations may be less prominent. It is a compromise between access to nature and light pollution.

Bortle 4 – Suburban Sky

  • Observers in suburban areas will find a considerable amount of light pollution, but brighter celestial objects like planets and the Moon are still easily visible. The Milky Way is generally not visible, and the sky is noticeably bright. Faint deep-sky objects will likely require binoculars or a telescope to be observed clearly.

Bortle 5 – Bright Suburban Sky

  • This class represents urban areas that experience significant light pollution. While brighter stars and planets are still visible, the sky is heavily washed out, and the Milky Way is completely obscured. Faint deep-sky objects are impossible to see without a telescope, and the environment is illuminated by the glow of nearby city lights.

Bortle 6 – Light-Polluted Sky

  • Locations in Class 6 are typically in the periphery of urban centers where artificial lighting dominates. Only the brightest stars and planets are visible, and the sky is a dull, murky gray. The Milky Way is completely invisible, and very little astronomical detail can be seen with the naked eye.

Bortle 7 – Moderately Light-Polluted Sky

  • As you move into more urban environments, the light pollution intensifies. The sky is overwhelmingly bright, and only the brightest stars are visible. The light from nearby cities creates a strong glow that makes it nearly impossible to observe faint stars or deep-sky objects. This class is common in larger cities.

Bortle 8 – Very Light-Polluted Sky

  • In cities with extreme light pollution, only the most prominent stars can be seen, and the sky is typically washed out with artificial lighting. The night sky may appear orange or yellowish due to street lights and city lights. Even with a telescope, the ability to observe deep-sky objects is severely limited.

Bortle 9 – Extremely Light-Polluted Sky

  • Class 9 represents the worst light pollution, typically found in the heart of large metropolitan areas. The sky is completely dominated by artificial lights, and very few stars can be seen with the naked eye. The Milky Way is entirely obscured, and observing celestial objects is nearly impossible without extremely specialized equipment

Figure 1 is an excellent resource from the European Southern Observatory that shows how the Milky Wat fares against light pollution at each Bortle Number. When I observe in Sudbury I am at a Bortle 5.7 and have no chance of making out the Milky Way and many deep-sky objects are bleached out. But nevertheless this is pretty good and I am grateful to have those skies. In Rockport were I often go in summer I am at Bortle 4.2 and the Milky Way seems to blink on and off. You see here the obvious advantage of the Observacar over a fixed site. Don’t like your Bortle Number and you just have to hop in your Observacar and drive somewhere else.

I have heard that AI based telescopes like the ZWO Seestar 50s and the Celestron Origin can figure out what they are pointing at, the so-called “solving of the plate,” in Bortle 8 skies. Take another look at Figure 1 again. You wonder how this is even possible. Add a near full moon and things get really dicey.

Amateur astronomers are ever in the search of or, covetous of, clear skies. Light pollution is one of those things that deprive us a fundamental element of what it means to be human. To see a sky unpoisoned by artificial light is to connect with the humans that first inhabited our planet. I wish you Clear Skies everyone!

The White Rabbit and the friction-less railroad

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Figure 1 – The White Rabbit or The March Hare (c) DE Wolf 2025

As I mentioned last week I spent the weekend in Newburyport, MA and on Plum Island. I took the image of Figure 1 in a shop. I was drawn to the White Rabbit in remembrance of Mr. White Rabbit, Esq. or the March Hare of Lewis Carrol’s Alice in Wonderland fame. Some of my readers had requested a break from Astrophotography and Astrophysics. That’s fine but one is never truly on vacation from physics – never more than a hare’s breadth away!

“… nor did Alice think it so very much out of the way to hear the Rabbit say to itself, “Oh dear! Oh dear! I shall be late!” (when she thought it over afterwards, it occurred to her that she ought to have wondered at this, but at the time it all seemed quite natural); but when the Rabbit actually took a watch out of its waistcoat-pocket, and looked at it, and then hurried on, Alice started to her feet, for it flashed across her mind that she had never before seen a rabbit with either a waistcoat-pocket, or a watch to take out of it, and burning with curiosity, she ran across the field after it, and fortunately was just in time to see it pop down a large rabbit-hole under the hedge.

In another moment down went Alice after it, never once considering how in the world she was to get out again.”

Thus begins Alice’s singular and most peculiar adventure. Poor Alice, she hasn’t really escaped physics but actually jumped right into it, so to speak. Of course, the rabbit represents the constrictions of our human world, where everything is on a tight schedule. We are told that “everyone is mad here” in Wonderland, and you very quickly start to wonder where it is that everyone is mad? Now more than a century and a half since Carrol penned the book we know about Einstein’s Theory of Relativity and the fact that the time here and now can be quite different there and now and that two simultaneous events here are not necessarily simultaneous there. Poor March Hare his pocket watch has become quite useless, or perhaps more accurately quite meaningless. Time and simultaneity have become quite meaningless in this non-Euclidian universe. While not often used in a anti-theological way, the facts of relativity make a strong case for a rational universe!

Anyway, dear Alice is in free fall along with the March Hare. Rabbit is worried about the time and Alice is just starting to understand the gravity of her situation. GRAVITY! Johann Carl Friedrich Gauss (1777-1855) explained that the force of gravity acting on an object, say an Alice or a Rabbit, is proportional to the volume of matter contained withing a sphere at some position in space. This means that while the force of gravity at the surface of the Earth is greatest and the force at the center of the Earth is zero. Therefore, if you were to drill a channel along a diameter through the center of the Earth, the object reaches the center at maximum velocity, starts its return journey, on the other side, only to reach zero velocity when it reaches the surface of the Earth on the other side. Ignoring the mathematics, it can readily be shown that it takes 42.25 min to reach the center. The object is a classical oscillator, going back and forth forever every 84.50 min.

We’ve ignored a few things here, like the crushing pressure, friction in the air column, and scalding temperatures. Mere technicalities!

But things get even more interesting. Suppose you were to drill a tunnel along a chord through the Earth between any two points on its surface, say between London and Paris, or between Paris and New York. If you had a frictionless railroad (that’s mighty good oil!), it would take precisely 82.5 min for the railroad to go between any two destination points!

Now this is of course all fantasy – as was the story of Alice in Wonderland. But it has been suggested that this mathematical paradox was in mathematician Lewis Carrol’s mind when he wrote the story of Alice ,

“A paradox, a paradox
A most ingenious paradox.”

Gilbert and Sullivan the Pirates of Penzance

I apologize for returning us, on vacation, to astrophysics. But it always comes to my mind whenever I see a rabbit resembling the March Hare; rabbits, hares for that matter, do not wear glasses nor pocket watches. Little girls do not float endlessly to soft landings in Wonderland. Still the world, indeed the universe, is filled with what might seem the paradoxical. Such is merely the reflection of the facts that the world is not flat nor time not relative.

From the Observacar – NGC 1398

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Figure 1 – NGC 1398 iTelescope T73 (c) DE Wolf 2024

It is spring, friends! The time change has passed and the sunsets later and they lead to warmer nights. I am at present trying to get trying to get my big eight inch Nexstar up and properly running so that I can finally do some planet observing.

Also, I have been venturing out to the wildlife refuges again. And I hope to have some good bird photographs for you again. This weekend I am going to Plum Island in search of white owls and piping plovers. Wish me luck

Figure 1 today is of the dramatic NGC 1398 galaxy and was taken using itelescope T73 in  Rio Hurtado, Chile just at the start of the New Year. As a reminder this is a 0.50-m f/6.8 reflector with a 26.93′ x 21.53’arc-mins FOV. 3 images with each RGB filtration of 120 sec each. I am really pleased with how the image came out. I see this and then remember that in my youth my telescope was a 60 mm Unitron Refractor! Times change.

NGC 1398 is a spectacular even majestic galaxy, standing out for its impressive structure and vibrant features. Located in the constellation Fornax, NGC 1398 it is what is referred to as a barred spiral galaxy. A barred galaxy is a type of spiral galaxy characterized by a distinct, elongated central bar-shaped structure made of stars. This bar runs through the galaxy’s nucleus and extends outward, from which the spiral arms of the galaxy typically emerge. The presence of this central bar distinguishes barred spiral galaxies from unbarred spiral galaxies, where the spiral arms directly emerge from the central bulge without a bar-like feature.

NGC1398 was first discovered by the famous astronomer William Herschel in 1835, and it is situated approximately 65 million light-years away from Earth. This stunning galaxy is part of the Fornax Cluster, a rich collection of galaxies that offers a wealth of astronomical discoveries. NGC 1398 is notable not only for its size and composition but also for the intricate spiral arms that define its shape.

In addition to the spiral arms, the galaxy is also surrounded by a faint, extended halo of stars that is common among many galaxies. This halo is made up of older stars and provides valuable insights into the galaxy’s formation history.

The central bulge of NGC 1398 is another fascinating aspect of its structure. This bulge is thought to contain a supermassive black hole, a feature that is often found in the centers of large galaxies. This black hole likely plays a key role in the galaxy’s dynamics and may even influence the formation of the spiral arms.

It is, I think, a curious point that when it comes to astrophotography for the sake of astrophotography, as oppose to astrophotography for scientific purposes, I haven’t graduated to that yet, we are drawn to certain objects because of artistic features. NGC 1398 with the delicate structure of its spiral arms in such an appealing object.

From the Observacar – Never Setting Messier 81 & 82

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Messier 81 (lower right) & 82 (M82) Celestron Origin image 60 min 360 exposure (c) DE Wolf 2024

Messier 81 (M81) and Messier 82 (M82) are located in the northern sky in the Big Bear or Ursa Major. They are named the “Bode’s Galaxy” and the “Cigar Galaxy,” respectively, They were cataloged by French astronomer Charles Messier in 1774 as part of his mission to identify and catalog celestial objects that could be mistaken for comets. Messier 81 is a spiral galaxy, while Messier 82 is a peculiar galaxy, often classified as a starburst galaxy due to its unusual structure and intense star formation.

These two galaxies are part of what are referred to as the M81 group, a collection of gravitationally connected and interacting galaxies. This pair dominates the group visually but it also contains several smaller galaxies, such as NGC 3077, NGC 2976, and NGC 2366.

Galaxies generally come in groups. The members of our Milky Way’s group, referred to as the “Local Group,” are extensive and include: the Milky Way itself, the Andromeda galaxy (M31), the Triangulum Galaxy (M33). Additionally, there are so-called dwarf galaxies: Large Magellanic Cloud, (LMC), Small Magellanic Cloud (SMC), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf Galaxy, Draco Dwarf Galaxy, Carina Dwarf Galaxy, Leo I and Leo II. Our Local Group also contains a variety of other smaller dwarf galaxies that are gravitationally bound to the larger galaxies. These include: Fornax Dwarf Galaxy, Phoenix Dwarf GalaxyAndromeda II, Andromeda III, and the WLM Galaxy (Wolf-Lundmark-Melotte). The extensive list illustrates the extent of gravitational clustering in the universe and by connection the incredible distances over which gravity extends and shapes the structure of the universe.

Messier 81, or Bode’s Galaxy, is one of the brightest galaxies in the Messier catalog and stands out due to its well-defined spiral structure. It is located approximately 12 million light-years from Earth and is part of the M81 group, which consists of a collection of galaxies in close proximity to one another. With a diameter of around 90,000 light-years, M81 is a relatively large galaxy, comparable in size to our Milky Way.

One of the most striking features of M81 is its spiral arms, which are richly populated with stars, gas, and dust. These arms are the sites of ongoing star formation, and the galaxy is thought to be relatively stable, with a low rate of active starburst activity. The central region of M81 contains a bright, active supermassive black hole that likely plays a role in regulating the galaxy’s dynamics. Its steady state contrasts sharply with the more energetic activity seen in its neighboring galaxy, M82.

Messier 82, known as the Cigar Galaxy due to its elongated, cigar-like shape. M82 is a peculiar galaxy, often classified as a starburst galaxy. This means it is experiencing an exceptionally high rate of star formation, far higher than typical galaxies like our Milky Way. The intense starburst activity in M82 is thought to be a result of interactions with nearby galaxies, particularly Messier 81.

Unlike the relatively calm Messier 81, M82 is a turbulent galaxy, with massive amounts of gas and dust fueling the rapid birth of new stars. The central region of M82 hosts a vigorous outflow of gas and energy, creating a dramatic galactic wind. This outflow is thought to be the result of the starburst activity and may eventually expel a significant portion of the galaxy’s gas, limiting future star formation.

The two galaxies continue to interact and there is some evidence that this gravitational interaction with M81 is responsible for the starburst activity of M82. They are believe to exchange material and may at some point merge with one another.

Never setting in northern skies, they are a favorite of amateur astronomers. The image of Figure 1 is a 360 frame 1 hour exposure taken with my Celestron Origin. I framed it so as to bring both galaxies into the image to suggest their gravitational pairing and interaction.

From the Observacar – The Pac-man Nebula

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Figure 1 – The Pac-Man Nebula in Monoceros (NGC 281) Celestron Origin 60 min 360 Frame Image (c) DEWolf 2025.

We have been tried and tested all winter, and at last there is the slightest hint of the coming of spring, No matter how hard I try I find it impossible to secure the mount on the tripod wearing gloves. And it is never a good idea to mix optics and hand balms. Anyway, the calendar says that next weekend is the time change and two weeks from that the equinox. So I retreat to the warmth of the Observacar and fantasize of warmer days. Soon enough, and never satisfied, I will be complaining of the humidity and bugs and once more retreating to the air-conditioned comfort of Observacar!

In my last blog I spoke about the naming choice between Thor’s Helmet and Flying Duck Nebula. I really lean toward the intrinsic nobility of the mythic. Today I want to talk about the Pac-Man Nebula. Now someone was definitely given free range here. The nebula is diminished enough without this last indignity.

Still on Monday night I spent a long while capturing it under, or through, somewhat less than perfect skies. The result is Figure 1. The name Pac-Man gets you thinking of diminutive things and it seems to look more like a celestial backfire than a majestic nebula.

The Pac-Man Nebula—a glowing, colorful cloud of gas and dust located in the constellation of Monoceros. The Pac-Man Nebula (NGC 281) is a H II region, which means it’s a large cloud of gas and dust that is predominantly made up of hydrogen. Note, what looks like a smudge in the center of the image. That is a classic Bode body where absorbant dust blocks the underlying light of the nebula. This nebula lies about 9,500 light-years from Earth and spans roughly 5,000 light-years across. It’s a beautiful region in the Milky Way, where new stars are being born in the dense molecular clouds of gas.

Like many other emission nebulae, the Pac-Man Nebula is lit up by the intense radiation from young, hot stars at its core. These stars emit ultraviolet light that ionizes the surrounding hydrogen gas, causing it to glow with a reddish hue.

In the figure, the cloud of gas takes on a distinct form, with a large, round “mouth” that resembles the iconic character of Pac-Man, about to “eat” its surrounding space.Its resemblance to the classic arcade character isn’t just a coincidence, but rather due to the complex interplay between the intense radiation from the stars in the nebula and the surrounding gas. The stars at the center of the nebula are carving out cavities in the surrounding hydrogen clouds as they push their stellar wind and ultraviolet radiation outward, creating a “bite” on one side of the nebula. Much like we saw Stellar Winds rip apart gas clouds in the Thor’s Helmet Nebula.

The Pac-Man Nebula is not only beautiful, but it’s also a star-forming factory. Within the cloud of gas and dust, young stars are being born. Some of these stars are still in the process of forming, while others have already ignited and are illuminating the surrounding nebula with their energy.

The Pac-Man Nebula contains many massive stars. These stars are so large and hot that they produce powerful winds that clear away the surrounding gas and dust, shaping the nebula. As they age, these stars will eventually explode as supernovae, enriching the surrounding space with heavy elements that will go on to form new generations of stars, planets, and perhaps even life.

The nebula also contains many smaller, less massive stars that are forming in the dense regions of the nebula. These stars will have a much longer life span than their massive counterparts, and they will slowly settle into a more stable phase as they mature over millions of years.

When a supernova occurs, it sends shock waves through the surrounding gas and dust, triggering further star formation. The energy released by these stellar explosions also spreads heavy elements (such as iron and oxygen) into the interstellar medium, enriching the gas clouds and helping to create the building blocks for new stars and planets. In mythological terms these represent the anvils of the gods.

From the Observacar – Thor’s Helmet NGC 2359

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Figure 1 – NGC 2359 the Thor’s Helmet Planetary Nebula (c) DEWolf 2025

This image is right off the presses. The weather here has continued to be snowy, icy, and cloudy. It’s been too treacherous to take out the telescope, Observacar or no! I am hoping that the recent thaw and melt will make it observing safe for this coming Sunday or Monday.

In the meanwhile, I was driven back to my favorite remote telescope, a 20″ beauty on the iTelescope.net in Chile known as T72. I had my eye recently on some wonderful imagrs of NGC 2359 referred to as the Thor’s Helmet or flying Duck Nebula.Thor’s Helmet sounds more mythic and besides lends itself to embeding music from Wagner’s “Ride of the Valkyrie!” So I decided to do some remote telescope imaging. I looked at the absolutely perfect all-sky camera from Chile and was absolutely sold.

First, the particulars about the telescope. PlaneWave Instruments CDK 20″ f/6.8, 3411mmFL, FLI ML16200, Blank,LRGB, SII,Ha,OIII,U,V,B,R,I Filters. PlaneWave Instruments L-500 Mount. Observatory: Deep Sky Chile at Rio Hurtado Valley, Chile – MPC X07. South 30°31’34.712″  West 70°51’11.865″ . Elevation: 1710m  MPC X07 

Figure 1 shows the results of 36 min imaging. I am very happy with it. Exactly what are we looking at here? This intricate and vivid planetary nebula is located approximately 15,000 light-years away in the constellation Canis Major, and provides a fascinating glimpse into the death of massive stars and the beauty of cosmic phenomena. Planetary nebulae, form when a dying star dramatically sheds its outer layers, leaving behind a hot, dense core, typically a white dwarf star. These white dwarves are incredibly dense and hot. They emit high energy radiation, which ionize the gaseous out layer causing it to emit light – hence the beautiful irridescent display here..

Here the story is slightly different. This nebula spans around 30,000 light-years across, and its distinct “helmet-like” structure is created by the star at its core—a massive hot Wolf-Rayet star, designated WR 7. Wolf-Rayet stars are huge, rare, and have intense winds that blow away their outer layers, shaping the nebula around them.

This color palette gives Thor’s Helmet a dynamic and vibrant look, as different parts of the nebula shine in various shades depending on the density and composition of the gas. The overall result is a mesmerizing scene.

Like all planetary nebulae, Thor’s Helmet will eventually fade away as the central star exhausts its remaining fuel and ceases to ionize the surrounding gas. Over thousands of years, the nebula’s brilliant glow will dim, and it will disperse into the interstellar medium, enriching the surrounding space with elements that will be incorporated into future generations of stars and planets.

In the case of WR 7 stars, however, its fate will likely be a more spectacular one. As a Wolf-Rayet star, it is expected to eventually explode into a supernova, an event that will release vast amounts of energy and matter into the surrounding cosmos. This final explosion will be the culmination of the star’s life cycle and could lead to the creation of a black hole or a neutron star.

And let us take note that today is the First of March. Meteorological spring is upon us!