Figure 1 – The Horsehead Nebula, Barnard 33, Celestron Origin, a 60 min, 360 frame exposure. (c) DEWolf 2025.

Today I’d like to continue our tour of the Orion Molecular Cloud Complex with the Horsehead Nebula or Barnard 33. It is one of my all time favorites, indeed the favorite of many people. Figure 1 is an image that I took of it with my Celestron Origin, a 60 min, 360 frame exposure. You can see it clearly positioned close to the Flame Nebula

The Horsehead Nebula is a dark nebula, which means it is a dense cloud of gas and dust that obscures the light from stars and other objects behind it. Within this complex, the Horsehead Nebula stands out due to its distinct shape, which is formed by a dense, cold cloud of dust and gas. It spans about 3,000 light-years in length, with the Horsehead itself measuring about 1,500 times the size of our Solar System.

Despite being a dark nebula, the Horsehead is illuminated by the nearby star Alnitak, which is part of the Orion Belt. The radiation from Alnitak causes the surrounding gas to glow, contributing to the nebula’s glowing red appearance in many photographs. The Horsehead Nebula owes its distinctive shape to the way light interacts with the dust and gas in the region. The Horsehead silhouette is formed by a thick concentration of dust and gas that casts a shadow on the glowing emission nebula behind it. This shadowy region is particularly dense, blocking much of the light from the stars and other gas clouds in the area, and giving it its signature look.

In photos, you often see the Horsehead Nebula in a striking combination of red and black. The reddish hue comes from the ionized hydrogen gas in the nebula, which glows under the influence of ultraviolet light from nearby stars. The dark, black shape of the nebula contrasts with the glowing gas, making it appear almost like an otherworldly creature—hence the name “Horsehead.”

Within the nebula, there are regions of intense gravitational collapse, where the dust and gas are coming together to form protostars. These protostars are still in their early stages of development, but they are the building blocks of future stars.

The Horsehead Nebula was first noticed in the early 20th century. However, its “discovery” wasn’t as a result of visual observation with the naked eye, but rather through photographic techniques that were becoming more advanced during that time.

The nebula was first photographed in 1888 by the American astronomer Edward Emerson Barnard, who is often credited with its discovery. Barnard was one of the pioneers in using long-exposure photography to capture celestial objects, and it was this technique that allowed him to detect the faint, dark nebula in the Orion Molecular Cloud. And it was long exposure that was key to contrasting dark regions against faint brighter ones.

Indeed, we can consider Figure 2, which is an 18 min exposure that I took with my Seestar 50s. This image required considerable image processing using Topaz Camera AI and even so is a little fuzzy or noisy. With the Seestar I find that the images benefit from three processes: sharpening, denoising, and upscaling, where the AI increases the number of pixels and fills them in.

Figure 2 – Horsehead Nebula Seestar 50s 18 min exposure (c) DEWolf 2024

Basically, I think that you will agree that Figure 2 is less distinct and sharp than Figure 1. This begins a not so much complicated as subtle and shaded discussion of signal-to-noise. But let me just concentrate here on the issue of signal. After all the famous signal-to-noise ratio is brightness divided by something. How much brighter is the Celestron Origin than the Seestar 50s.

I heard in a YouTube tutorial that it was about 25 x brighter and I wondered where that came from. (This little mathematical calculation is for those of you who care!).

Suppose that the flux at the surface of the telescope objective is X (Watts/in²) then

(Light collected by Origin/light collected by Seestar) = X (5.98²-2.48²)/X 2² = 7.40.

This is because, Origin has a 5.98 ” objective and the camera occludes a 2.48 ” circle, while the Seestar has a 2 ” objective.

Next, we have the collection efficiency inside the telescope which is determined from the solid angle

(Collection eff. Origin/Collection eff. Seestar)=(f/#Seestar/f/#Origin)² =(5/2.2)² = 5.17

Finally, we have to consider that ratio of light collected by an Origin pixels to that collected by a Seestar pixel. This is given by the ratio of the areas of the two pixels

(Pixel Collection Origin/Pixel Collection Seestar) = (2.4 um x 2.4 um)/(2.9 um x 2.9 um) = .685

Thus, the brightness ratio  = .685 x 5.17 x 7.40 = 26. You heard it here first! Typically with my Seestar 50s I would take something like a 26 min exposure. You can capture this many photons in 1 min with the Celestron Origin. Astrophotography is a game of how many photons you can collect.

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.