Asteroid Vesta - every other day from April 26 to May 2, 2025 as seen from my backyard.
A Bullet With Our Name on it.
They are dark, tiny and almost invisible - yet they can change life on earth in an instant.
Asteroids.
Relatively small among space objects, these are especially hard to see in the darkness of space. Even with telescopes, they are hard to find due to their distance and low reflectance of sunlight. But more than stealth, what makes them deadly is speed. With velocities of up to tens of thousands of miles per hour - they are like cosmic bullets zipping through space, silently. And from time to time, one of them has our name on it.
Of all astronomical phenomena touching the earth, perhaps next to sunlight, these otherwise innocuous space rocks can have the greatest ability to impact life on earth. As some of them already have.
Lunar rilles seen from my backyard through a Celestron 5” f/12 telescope and a 2X Barlow.
What is common between an old woman, a fox, a three legged toad, a rabbit, Jack and Jill?
All of the above have been characters supposedly plastered on the face of the moon, based on folklore in different countries around the world. Storytellers have used their imagination to explain the light and dark patches that can be seen by naked eye on the moon. We now know that these features called maria - are made of ancient solidified lava that flowed out from the lunar mantle and settled in impact basins eons ago. Humans have given them beautiful names like the “Sea of Tranquility” and “Sea of Serenity”. The other prominent features that can be seen by naked eye on the moon are larger impact craters. These include Copernicus and Tycho with signature rays of ejecta radiating in all directions reminder, of a violent past when meteorites routinely collided with the moon.
Rima Hyginus and Hygins crater seen from the Lunar
Reconnaisance Orbiter cameras.
[NASA/GSFC/Arizona State University]
Earthbound small telescopes can see more, including the smaller craters, mountains, and a rather unique feature comprising of long sinuous grooves known as rilles, which appear like wrinkles in the moon's skin. On January 17, after struggling with poor seeing and a hopelessly roiling atmosphere while trying to image mars, I settled on the moon. I have imaged lunar craters before - but this was the first time I became aware that lunar rilles could even be seen with backyard telescopes.
Two specific rilles I focused on are known as Rima Hyginus and Rima Ariadaeus. Both lie to the south of the Sea of Serenity. Rima Ariadaeus the longer of the two is 300 Km long and 5 km wide (compare with the Grand Canyon at 446 Km long and up to 18 Km wide). However this was harder to see and it appeared as a very thin line. Rima Hyginus, though smaller at 220 Km long, on the other hand, appears clear as a shallow "V" shape with the Hyginus crater at its vertex. But there is only so much you can see from a quarter million miles away.
A Nasa spacecraft known as the Lunar Reconnaissance Orbiter (LRO) continuously orbits the moon, one of its missions is to make 3D maps of the surface. Flying merely 30 miles above the moon its cameras yield much more detailed images such as the second one above. One can see what appears as a featureless lines in the first picture are sinuous paths riddled with a chain of closely spaced craters.
Craters of another kind
It turns out these craters are of igneous origins. Unlike impact craters that are abundant on the surface of the moon, these have rimless rounded edges, are not nearly as circular and have no ejecta blanket from scattered debris. The most favored theory is that these are depressions like sink holes, caused by collapsed tops of lava tubes. Geologists believe these form in the same way as lava tubes on earth but in the absence of an atmosphere, are larger.
A single pit from a larger sinuous chain. Source: LROC, NASA/GFC/ASU
Chain of collapsed pits to uncollapsed segment. Source:LROC, NASA/GSFC/ASU
Lava tubes on earth form when an open channel lava flow develops crusts on the sides. Over time, these expanding crusts meet in the center forming a roof, resulting in a tube with lava still flowing in it. Lava tubes on earth do not get “plugged” when the lava cools. Rather, as the flow diminishes, the liquid level drops forming hollow cavities within them, like caves. Scientists believe lunar lava tubes may be similar, hosting caves within them.
Nāhuku- Thurston Lava Tube, Hawaii
New Age Cave-Men
In 1962, scientists first proposed that drained lunar lava tubes can be used for sustained human habitat. Unlike on earth, the moon has no atmosphere to protect the human bodies from space hazards such as cancer causing cosmic rays and coronal mass ejections during solar storms. These structures provide natural protection reducing the amount of build required with man made materials.
The world is in a new race to create sustained human presence on the moon and other planets, extending our species' chance of survival. On the moon, caves may go from being a quirk in planetary geology to the first base of organized human presence, much like it began on earth. If this happens, then at the leading edge of our civilization, will essentially be handful of new age cave men with modern day sticks and stones, forging our future in new worlds.
Concept of Toyota LUNAR CRUISER, a crewed pressurized rover, expected to launch in 2029
I stopped walking, squinting to focus, eyes scanning the area again cautiously. In all these years of looking, the moment of the find has not changed much in character. An uncomfortable mix of uncertainty and optimism, maybe even a subconscious holding of breath in case I disturbed the universe, usually culminating in a moment of relief.
That indeed was it.
Like a faint apparition in the nautical twilight of Boise, Idaho, beyond an empty parking lot next to a tree, hung the unmistakable form of a comet. My first naked eye comet with the ungainly name of C/2023 A3 Tsuchinshan-ATLAS (more on that later).
Comet C/2023 A3 as seen from Boise, Idaho on Oct 14th (handheld, cellphone shot)
Wide angle view of Trifid and Lagoon Nebulae, Sep 20, 2024. Photo credit: Purnendu Gupta
The Lagoon nebula is a popular late-summer / early fall target for stargazers in the northern hemisphere. Perched above the tipped "teapot" of Sagittarius it disappears below the horizon quickly in the following months. By that measure, this Friday, September 20th, two days before the official start of fall, was past its prime viewing window. Yet, I chose to give it a shot.
The result was the image above. A two-for-one wide angle view of two nebulae, the Trifid on the left and the Lagoon on the right. Light that is more than four thousand years old, gathered over 52 minutes through a narrowband filter. The image is rich in red Hydrogen-alpha light which is the signature of emission nebulae. To me, the swirling clouds around a brighter core of the Lagoon looks like the whorls in rose petals. The nearby Trifid has menacing dark streaks across its face. Unfettered by such features, the Lagoon might appear to be a calmer place. Yet, nothing could be farther from the truth.
The word "Aurora" comes from Latin. In Roman mythology and Latin poetry it is the name of the goddess of dawn. It was first used by Gallileo in the context of the atmospheric phenomemon. The word pairs “Aurora Borealis”, or “Northern Lights”, conjures up imagery of colorful, curled flows of light tucked away in the high northern latitudes, somewhere in the Nordics or Iceland. Rarely does this phenomenon descend from the earth's poles to the lower latitudes. In the contiental United States, that means it does not extend beyond northern states like Minnesota or Alaska. Viewing the Northern lights has been on the bucket list of low latitiude dwellers like myself.
Spring of 2024, May 11th was one of those very rare occassions when the "goddess of dawn" visited us right here in my New Jersey backyard at the lowly 40 degrees north latitude.
A string of eight galaxies known as “Markarian’s chain” with 14 more of their visual neighbors. A personal first of 22 galaxies in a single shot with the new Apertura 72mm f/6 refractor. Shot from my backyard on May 1st at about 11 pm.
Watch closely. Those little pools - of light. Take away their names, And they become a swarm Of fireflies.
The North American total solar eclipse of 2024 was a long time coming for me. Since missing the opportunity in 2017, I had rationalized I would do what it takes to get in the path in 2024. I reasoned that my daughter who was only three years old then would be ten and build a much better memory of it. The wait had effectively been for seven years, and I was ready to be mooned!
Taming The Digital Wolves
This would be my first total solar eclipse ever. I wanted to watch the event with my own eyes without having to fidget with camera settings and looking at an LCD screen. As a result my camera had to be automated. I considered several eclipse automation software and settled in on one called SetNC which was free and yet effective. Some helpful folks over at cloudnights.com shared their experience with the software and recommended tweaks to defaults based on their 2017 eclipse experience. I had tested it out and it seemed to work.
Also a regular tripod would not suffice. In order to stay pointed at the sun for the minutes of totality, the mount had to be able to track the sun automatically. While I already had an "alt-az" mount - it did not pack very well even as check-in luggage. I experimented with a more portable tracking mount that would comfortably fit inside a carry on bag and having played with an iOptron skyhunter, settled on a Skywatcher AZ GTI mount. It was battery or AC operated alt-Az design but with an off market wedge and a Sky-watcher provided firmware update, this could also become a lightweight equatorial mount. I was not going to try roundaout ways to polar align by day (without a visible pole star) for the eclipse, so al-az was cool, but I could not resist the prospect of this being a dual purpose mount for future night time astro as well. I had tested both pieces to understand their little quirks and how to make them play well together.
Location location location
The last two days leading up to April 8, 2024 had been the culmination of a series of changes to our travel plans.
The initial plan was to go to Texas and observe the 3 minutes of totality from the comfort of my sister 's place, but the weather gods intervened. Over the last 20 years, April generally was cloud free in Texas while rest of America on the eclipse path was iffy. This was one of the exception years. A weather system was moving across most of American eclipse path. My backup location at Rochester, NY was also predicted to be clouded out. I had become an expert on specialized weather apps such as Astrospheric, that spewed hourly predictions days in advance for a fee. It seemed Vermont was going to be the place near us with the least amount of clouds. The Canadian weather model which is supposedly the most accurate for cloud cover predicted a 16% at the time. However hotels in the path of totality were ridiculosly expensive (somewhere like 4-5x of regular price). We decided to stay just outsize the path of totality in Lake George, NY but drive in to the most favorable location on the day of based on weather reports.
Interestingly, the timing of contact has been predictable for 2000 years, since the Babylonians saw the repeating pattern in eclipse records, but they did not know why or where the next one would occur. The location became predictable only about 300 years ago since Edmund Halley applied Newtonian gravity to the problem, for the first time predicting an eclipse in England. While we were beneficiaries of such precision, the weather prediction was another story.
Verity in Vermont
Based on predictions the prior night, we were in a small town in Vermont in the path of totality. We waited as the moon’s shadow sped towards us with a land speed three times that of a commercial jet.
In the middle of a pleasant spring day, an eerie twilight set in. The air became chilly, as the last sliver of the sun disappeared. Final rays that escaped through the craters on lunar limb, put the “diamond ring” on show. And then, all that remained was a black hole in the sky.
We stared at the dark face of the moon, with wispy solar corona streaming in all directions around the edges. At a few spots along the rim, red plumes of solar prominence emerged, visible by naked eye. It was as if bits of our host star was oozing out into space. The prominences looked tiny, yet any one of them would be larger than the whole of the earth. Flanking the scene, two bright dots appeared in the darkened sky - Venus and Jupiter in a single line, the plane of the ecliptic.
For the shortest 3 minutes ever, and for what will be the last time in the next 20 years in America, a cloudless mid-day had turned into night.
Growing up in a big city almost anywhere in the world breeds a certain disinterest in the sky.
Observing stars in the night sky just isn't something big city people do, or fill any part of their busy lives thinking about. So for most of my childhood, which was in a corner of a big city, I never really developed a feel for the night sky. There was a bookish understanding of stuff up there. Planets were things that existed in text books. The sun moved between imaginary lines of tropics in diagrams of geography lessons. A school teacher once mentioned that সপ্তর্ষি মণ্ডল (the Bengali name for the Big Dipper in the Indian sky culture) was a constellation which looked like a question mark if one looked north at the dead of the night. I only had a vague idea of where "north" was - thanks to a tiny little compass tucked away in a drawer in my grandfather's writing desk. We lived in a bungalow style home wth an open terrace. During warm summer nights, especially with power cuts which were frequent then, my parents and I sometimes went up there to catch a cool breeze. I have vague memories of seeing the moon. But trying to find a constellation at an unearthly hour was an adventure too far. I had no idea where or how to begin. Then there was in a monthly magazine a series titled কালপুরুষ ("Kalpurush") authored by a famous writer of the time. The title stood out as strange, mysterious and memorable in an awkward way. It literally translated to "temporal man". Though I had no idea what it really was about. I would later learn in the vedic constellation nomenclature, the name was a reference to Orion the hunter. But for that time, the universe lay perfectly hidden behind the everyday things we did in the pursuit of happiness.
Temporal Man
In the four decades that passed, my own pursuits took me to major cities in India (Delhi and Mumbai) and thereafter to the United States. And eventually I had the good fortune of moving to the suburbs of New Jersey where light pollution had not fully enveloped the night skies yet, and life at night was not a mad rush to get ready for the next day of work. With books, and then phone apps as a guide, I slowly taught myself how to read the night sky. Armed with a digital SLR camera that I already had and a pair of astronomy binoculars which I bought, I started my journey into the world of backyard astronomy and astrophotography. These modest tools would become my magic wands to lift the veil of darkness. And one of my first adventures would involve chasing Orion.
Into a Sea of Stars
Somewhere between then and now, ten years had passed and my flirtations with the hobby had grown into a steady affair. This night in 2024, was a chilly February night with a few wispy clouds. I opened my front door for a "check in" on the universe before retiring for the night. Centered on the vaulted arch of my doorway was this starry humanoid figure majestically towering above me. Orion the hunter, It was by now a very familiar friend. Betelgeuse on its left shoulder, was visibly ruddy, as was Aldebaran, the eye of Taurus to the far right. There was also no mistaking Sirius the dog-star at its left foot. The bright "eye" aside - I could see the whole Canis Major constellation down to the dog’s tail. In my mind, for a moment every vestige of human settlement below faded away. I felt like I could take a step forward from the threshold of my home and dip into a sea or stars.
Hello Darkness
I had to pause to take a picture. This was a single shot with an SLR on a tripod. I threw in a clip-in light pollution filter to suppress the amber glow of sodium-vapor street lamps. A few tries later - I landed on this single 20 second exposure that did the trick. And after a little abracadabra on the computer - it was just perfect. Only in hindsight I realized that ten years after my first rendezvous, I had come a full circle standing face to face with the timeless “Temporal Man” again.
From being blind to a whole universe that lies hidden in plain sight, to being able to open the front door and step into a sea of stars - many of which I know by name - has been a long and rewarding journey into realms I did not imagine existed. And for that, I shall remain eternally grateful to life.
While most major meteor showers originate from comets, the Geminids are among a few believed to originate from an asteroid. The source is the object called 3200 Phaethon. It is known as a "rock comet" since it had a trajectory like a comet but had no tail . The object was discovered by famous American Astronomer Fred Whipple who realized the object was connected to the meteor shower. Due to its close approach to the Sun, Phaethon is named after the character of Greek myth who drove the Sun-god Helios' chariot. 3200 Phaethon was discovered on Oct. 11, 1983, by the Infrared Astronomical Satellite..
A Geminid in Orion
My 2023 Geminid imaging setup included a DSLR mounted on a start tracker and set up for 3 nights in a row in my backyard with a self timer attached. Despite one lost day to a false start, the resulting composite shows seven Geminid meteors imaged over the nights of Dec 13th to 15th, 2023. The imaging duration spans the predicted peak night of Geminids in 2023.
The image on the left is a crop from the image above. This frames up a single Geminid meteor streaking across the constellation of Orion. It originated near Betelgeuse and travelled past the easternmost belt star, Mintaka.
All images were taken using a stock Canon 70D DSLR on a tracked mount with a 11 mm ultra wide lens at its widest setting, ISO 800 and 10s exposure. No filters were used.
composite showing seven Geminid meteors imaged over the nights of Dec 13th to 15th, 2023. The imaging duration spans the predicted peak night of Geminids in 2023.
Where do stars like the sun go when they die? At five billion years old, our sun is a middle aged star. It is also a middle class star, in the stellar spectral classification (yellow G type). When stars of this type reach the end of life, they do what humans do at the end of their working lives. They retire.
That’s right. They do not explode into a supernova like their big brothers, or collapse into black holes like their superstar cousins. They gently walk into ... the sunset. And when they do, they leave behind what is known as a planetary nebula like the one you see in the image above. The Helix Nebula is also known as the Eye of God, for its unique shape. The nearest example of its kind, it is at about 650 light years distant in the constellation of Aquarius. The image above was shot from my backyard in November of 2022 and is light gathered over an hour and a quarter. The image below is a false-color composite of the same, in visible and invisible “light” as seen by four special purpose NASA telescopes that see in different wavelengths.
Helix Nebula, Composite X-Ray, UV, Optical, Infra Red Source: Nasa
Stars are nuclear fusion reactors that exist at a self adjusting balance between the inward pull of gravity and the outward pressure of hot fusing matter. A little bit like a balloon that exists at the sweet spot between the squishing pull of its skin, and the swelling push of the air inside.
A star first lights up when fusion is triggered in the core of the proto-star, among the simplest atom of all - primordial Hydrogen that have atomic number one. This is forced by enormous gravity to combine with its neighbor transforming into the next heavier element in the Periodic Table, Helium, with atomic number two. As all hydrogen is exhausted, three of these Helium atoms will combine to form Carbon with atomic number six and so on. The nuclear alchemy goes on to magically cook heavier elements from lighter ones releasing energy in the process.
About 12,000 years ago, the progenitor star of the Helix nebula started to run out of its hydrogen fuel. The star cooled some and lost some of its ability to hold itself up against gravity. The core shrank, and the outer layers slipped away from its grip into space cooling and expanding into a red giant. This was the end of the “middle class sun” phase of life of the star. Any planets in that solar system experienced the last sunset as the shell of expelled gas engulfed the inner planets just as our own sun would engulf Mercury, Venus and possibly the Earth.
The Star Within a Star
Once the outer veil got lifted what lay exposed was the star's stopped nuclear engine. While no longer undergoing fusion, it is held up by another force known as electron degeneracy pressure. A bright core made mostly of a soup of electrons, carbon nuclei and some other elements, on its way to becoming a white hot midget star - a white dwarf.
A white dwarf contains about half the mass of the original star but is compressed by gravity into a ball merely the size of the earth or only 1/100th of the sun’s original diameter. As a result the densities are enormous. A tea spoon could weigh as much as an average car on earth. For comparison, a spoon ful of the sun’s core would be much lighter at only 750 grams.
By the time the white dwarf forms, the expelled shell has not had time to go very far - and is perhaps a light year or two away from the core. Instead of being a perfect sphere, the expanding shell takes on beautiful shapes due to pre-existing asymmetries. The radiation from the white dwarf core lights up the expanding gas in concentric shells of colors. The Hydrogen glows red and the Oxygen glows blue and green. Like a cosmic flower in final bloom. While the “retired” white dwarf will last many tens of billions of years, the shells of the nebula around it will quickly fade away.
Forget Me Knots
In 1996, a closer look into the Helix through the Hubble Space Telescope revealed some knot like structures, that were observed to lie in a ring pattern within the outer shell. These appear to be comet-like with a head and a tail pointing radially away from the core of the system. First discovered in the Helix, they were later found in many planetary nebulae. These knots were found to be the size of our solar system formed as the surrounding lighter gas got eroded and stripped back by the stellar wind and radiation from the central white dwarf forming finger like shapes due to a phenomenon known as the Rayleigh-Taylor instability.
There are some theories that suggest that the origin of these knots may result from interactions of the progenitor star with its binary partner. But since the shell is only a couple of light years in diameter wide, the distances are perhaps too small for typical two star systems. Yet another theory suggests these could be remains of supersized comets the size of planets - the likes of which have not been seen before. A more likely explanation may have to do with remains of large planets that orbited the original star. As the star expanded to a red giant, these bodies may have continued to orbit "inside" the parent star. Over thousands of years, as the stellar wind and radiation from the white dwarf stripped away the lighter gas, all that remained are these comet like streams with the "tails" like little flags of existence.
Was there life on any of these worlds? Evolution that spanned millions of years and civilizations that thrived for millennia? If so, these cometary knots may be the only signs that they were ever here.
Imaging Specs:
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25x180s light frames (total 1 h 15 min integration) with calibration frames. Optolong L-enhance narrowband filter. ASI294MC Pro cooled camera. Guided exposure with Celestron 127 SLT Mak-Cass on AVX mount
