Astrophotography: The Sword of Orion and The Alnitak Region in Orion

A) The Sword of Orion, featuring the Running Man nebula (NGC 1973/5/7) to the top and the Great Nebula in Orion (M42/NGC 1976) to the bottom. 

Photographic Information:

Imaging location: Thomson, Singapore (Light pollution: White zone/Inner City)

Date of data acquisition: 31 January 2014

Exposure Details: ~45min, 800mm FL at f/4

Camera: Canon EOS 600D Unmodified

Stacked with DSS, adjustment of curves and colors in Adobe Photoshop CS6. 

Description:

The term 'nebula' is a very generic term that can mean quite a number of things. The word 'nebula' actually originated from the latin word for 'cloud', and can therefore be used on almost any astronomical object that appears fuzzy looking. In this case, however, it means something much more specific, and that is a stellar nursery; a place where stars are born. 

In this image, vast swaths of blue and red cover the image, and these represent giant clouds of gas and dust. Quite literally, what you are looking at is stardust - stardust which form the ingredients that future stars are made of. 

The blue coloration in the image originates from starlight coming from the bright young stars reflecting off the nebula. Most of the stars here are O-class stars, which are the largest, brightest and hottest stars in the Universe. The intense light emitted by these stars reflect off the diffuse hydrogen clouds, giving a soft bluish glow. 

On the other hand, the red coloration represents something more interesting. O-class stars, with surface temperatures ranging tens of thousands of degrees, emit copious amounts of high energy ionizing radiation. Large amounts of ultraviolet light strip away the electrons from the interstellar hydrogen, leaving behind its positive nucleus. As the electrons recombine with the nuclei to re-form atomic hydrogen, it passes through a series of energetic transitions. Because of the distinct energy gaps between electron shells, the wavelength of light emitted during these transitions is the same. One such transition, in which the electron drops from the third energy level to the second closest to the nuclei, produces a very precise wavelength of light. This emission line is known as hydrogen alpha (HA), and produces red light at exactly 656.281 nanometers. 

The importance of hydrogen alpha emissions is that it gives us an idea of the composition of nebulae. When large amounts of HA is emitted, it implies that large amounts of atomic hydrogen exist in the nebula. Atomic hydrogen is important because it forms the main ingredient that triggers star formation. 

Even despite imaging from close to the heart of a highly light-polluted city, details of the outer nebulosity are visible. Exceptional weather conditions, as well as taking as many sub-exposures as possible, contribute to pulling out faint detail in astrophotography. 

B) The Alnitak Region in Orion, featuring the Flame Nebula, Horsehead Nebula, and of course, the star Alnitak. 

Photographic Information:

Imaging location: Thomson, Singapore (Light pollution: White zone/Inner City)

Date of data acquisition: 31 January 2014

Exposure Details: ~30min, 800mm FL at f/4

Camera: Canon EOS 350D Modified (IR Filter removed)

Stacked with DSS, adjustment of curves and colors in Adobe Photoshop CS6. 

Description:

The Flame nebula and Horsehead nebula, like the Orion nebula above, is a diffuse nebula where stars are born. Unlike the Orion nebula, however, the Flame and Horsehead undergo very little reflection nebulosity. The main emission line coming from these two nebulae are from Hydrogen Alpha, which gives it the characteristic red hue. Due to the colour processing however, the hue is shifted towards magenta rather than its true colour. 

The bright star in this picture is Alnitak, one of the brightest stars in the sky, and the westernmost star of Orion's belt. Like the young stars in the Great Orion Nebula, Alnitak is a massive O-class star, producing violent amounts of ionising radiation. The relentless burst of energy from Alnitak is what drives the incandescent nebulosity of the Flame nebula. 

The horsehead nebula is actually an absorption (dark) nebula, silhouetted against the soft glow of an emission nebula. Without this 'curtain' that lights up from behind, we wouldn't be able to see the horsehead in visible light. Even then, the horsehead is typically regarded as a challenging astronomical object to see and image because of its dimness. 

In order to bring out the horsehead, especially from such a highly light polluted region, a modified DSLR camera has to be used. Because the hydrogen alpha line in the visible spectrum lies so close to the infrared, unmodified DSLRs are very insensitive to such wavelengths, as are the human eyes. As such, the removal of the in-built UV/IR filters and its subsequent replacement with a clear glass plate will bring up the sensitivity of the sensor to these wavelengths, allowing the horsehead to appear. 

Our place in the Cosmos, and Reflections on Epistemology from a Scientific Perspective

“The human race is just a chemical scum on a moderate-sized planet, orbiting around a very average star in the outer suburb of one among a hundred billion galaxies”

The above quote, as famously put by Professor Stephen Hawking, aptly places our place in the universe in perspective. The human race is but one of billions of species that have walked on the Earth, and the Earth is, on planetary scales, a very average planet, orbiting a very average star. The sun is just one out of the estimated three hundred billion stars in the Milky Way galaxy, which is in turn a pretty mundane collection of stars in the Universe where at least a hundred billion others exist. If there is anything to be said about our place in the universe, we can be almost certain that we are nowhere privileged. We are but a grain of sand in an endless ocean.

As if being insignificant weren't enough, we could even see ourselves as a 'chemical scum’. The major elements that make up the human body, aside from primordial hydrogen, were cooked up in the hearts of stars that have lived and died. We are made up of nuclear ash, a chemical waste from the guts of dead stars. The elements that make up you and I are no more special than a chunk of rotting log.

For centuries, we have pondered about our place in the Universe – it seems almost as though mankind has had an obsession with wanting to be in a special position, one in which all of existence revolves around.  With the geocentric model of the universe being mostly unchallenged for over a millennium, the advent of Copernican heliocentrism seemed to have kicked start a wave of new discoveries that relegated our position into the distant periphery.

Perhaps, then, we shouldn’t quite determine how special we are from our literal place in the cosmos, or the reductionist perspective of the individual elements that make up our bodies. After all it isn’t a matter of substance that makes us who we are. Human life, as many would agree, is worth more than its weight in gold. Life differs from non-life not in terms of substance, but in terms of information. Digital information, arranged in bits of the nucleotide sequence that form the library of blueprints that make up all organisms.

It is almost unarguable that the trait that distinguishes us humans from any other species lies in a single organ: the brain. Not only can information be transferred in the form of genetic language from ancestor to descendant, it can now be stored, understood, and processed in a multiplicity of ways, limited only by the complex circuitry of neuronal complexes. Although the brain isn’t unique to humans, the ability of human brains to comprehend the natural world to such great depth beyond any other species is what has enabled us to dominate the globe. 

Furthermore, the ability of the human mind to comprehend the workings of the universe stretches above and beyond the purposes of hunting or maintaining survivability. It is more than just a curiosity of runaway evolution. It represents, above all, the universe understanding itself. We are in the universe, and a very small part indeed, but in some sense, the universe is also in us.

One video that I came across some time ago that inspired me to make this post is a speech made by physicist Dr. David Deutsch. His speech at the TED talks, titled ‘The Chemical Scum that Dream of Distant Supernovae”, describes what knowledge actually is. The ideas here represent what insights science brings to epistemology, or the philosophy of knowledge, and how this perspective of what knowledge actually is relates to our unique position, metaphorically speaking, in the universe.

The main part that I found incredibly thought provoking was his description of what knowledge is, with reference to Quasars billions of light years away. It is also this amazing speech that I would end this post with. For convenience, as well as for the benefit of those who are unable to view the video, I have typed out a slightly paraphrased transcript of what he said in the video below.

“Look out even further than [the Earth], with a telescope, and you’ll see things that look like stars. They are called ‘Quasars’. Quasars originally meant ‘Quasi Stellar Object’, which means things that look a little bit like stars.  But they’re not stars, and we know what they are. Billions of years ago, and billions of light years away, the material at the center of a galaxy collapsed towards a supermassive black hole. And then, intense magnetic fields directed some of the energy of that gravitational collapse (and some of the matter) back out in the form of tremendous jets, which illuminated lobes the brilliance of a trillion suns.

The physics of the human brain could hardly be more unlike the physics of such a jet. We couldn’t survive for an instant in it; the language breaks down when trying to describe what it would be like in one of those jets. It would be a little like experiencing a supernova explosion, but at point blank range, and for millions of years at a time.  And yet, that jet happened at precisely such a way, that billions of years later on the other side of the universe, some bit of ‘chemical scum’ could accurately describe, model, predict, and above all, explain what was happening there in reality. The one physical system (i.e. the brain) contains an accurate model of the other (i.e. the quasar). It’s not just a superficial model of it (although it contains that as well), but also an explanatory model embodying the same mathematical relationship and same causal structure. Now that is knowledge.

And if that weren’t amazing enough, the faithfulness with which the one structure resembles the other is increasing with time, and that is the growth of knowledge. The laws of physics have this special property: physical objects as unlike as they could possibly be can nevertheless embody the same mathematical and causal structure, and to do it more and more so over time.

We are a chemical scum that is different. This chemical scum has universality. Its structure contains, with ever-increasing precision, the structure of everything. This place, and not other places in the universe, is a hub, which contains within itself the structural and causal essence of the whole of the rest of physical reality. So far from being insignificant, the fact that the laws of physics allow this, or even mandate that this can happen, is one of the most important things about the physical world. “

An Introduction to this Blog

Good Day to all my Readers,

I have created many blogs in the past which I have since abandoned, and I'm honestly not sure if this will be any different. I have dedicated it to writing about astronomy and science, and perhaps an extension of these into philosophy. 

I guess this will be where I keep my random musings about astronomy and science in general, as well as my personal path in amateur astronomy and astrophotography. Having been living a city life my entire life, I have hardly got to experience the serenity of nature, nor the beauty of the milky way from the suburbs. 

I have always had a passion for astronomy every since my childhood days, and I have been in the hobby of amateur practical astronomy for about 6 years. I'm also interested in photographing the night sky, and capturing the wonders of the universe on 'film'. As such, I will also be posting my pictures that I have taken, which will probably mostly be from Singapore. Hopefully, this will inspire others living in the city, who may not find it easy to travel outwards into rural areas, to engage in this delightful hobby.

Thanks for dropping by and enjoy your stay!

~ Ivan