Amateur astronomy: from the craters of the Moon to beyond the Milky Way
Not only Hubble and James Webb take breathtaking pictures of the far corners of the universe. Around the world, amateur astronomers and citizen scientists point their home telescopes in their gardens or verandas towards the stars. Like astronomers of past centuries, they gaze at the night sky with the same wonder, but with better equipment and computer-controlled, searching for planets, comets, stars, galaxies and nebulae. Often their discoveries make important contributions to science. This article shows a few images from the archive of my uncle Johan Bonne, who watches the night sky from Antwerp in Belgium and sometimes in France.
Text: Kathelijne Bonne. Photos: Johan Bonne.
the night of 21 June 1969, young Johan slid out of bed to turn on the
television and to watch Neil Armstrong descending the steps of the lunar lander to
make history as the first man on the moon. Johan was then one of millions of
viewers of all ages worldwide who were enraptured by astronomy and space travel from that moment onwards.
More than half a century later, on the night of 13 August, my sister Helena and I rode our bikes down to the natural area of the Durme river to watch falling stars. Even under a hazy and overlit Waasland sky, the streaks of light of the Perseids, burning remnants of an ancient meteor, were easy to see. Not long after, we had a get-together with uncle Johan to look at his homemade space photos and learn more about space photography. The idea that those images were taken with nothing less than curved spacetime between an imperfect human eye and an unfathomable distant celestial body, without space agency intervention, is quite astounding. Thanks to citizen space photography, those distances seem a little shorter and the stars a bit more tangible.
Johan gave permission to have some of his pictures published, starting with the Moon.
Tycho, Kepler and the Monolith
171 years after the first surviving picture of the Moon was taken, by John Adams Wipple in 1852, Johan took the above picture. It shows the Tycho crater, one of the Moon's most striking features with clearly visible rays running from the center. This huge crater has a diameter of 85 km and a depth of 4850 metres - for someone walking around in Tycho, the relief must be truly flabbergasting. The crater formed by a giant meteorite impact, which blew away rock debris to all sides, creating the white rays, ons of them reaching all way into the Mare Serenitatis. The meteorite struck about 108 million years ago, which is quite recent by Moon standards. Earth was then under the warm Cretaceous Period, which came to an abrupt end 42 million years later due to the meteorite that killed the dinosaurs. But almost all traces of that fateful impact have disappeared in the wheels of plate tectonics and in the bustle of life, as Earth is an active planet. On the moon, by contrast, all the scars on the austere surface remain for lack of erosion and internal dynamics (which would have stopped more than a billion years ago). The moon itself was created more than 4 billion years ago by an utterly transformative impact between Earth and dwarf planet Theia.
Tycho is named after the aristocrat astronomer Tycho Brahe of Denmark (1546-1601), who made important astronomical observations just before the invention of the telescope. The world was then in full identity crisis: was Copernicus right and was Earth not at the center of the universe after all? In 1572, Tycho witnessed a celestial explosion or nova, now known as the Tycho supernova. This prompted him to reject the Aristotelian dogma of the static unchanging world; the universe does not stand still, it moves and it evolves, and we are all part of that world in motion. His progressive ideas caused him to fall into disfavor with the Church and King of Denmark, and he left his home country. In Prague, he was appointed official imperial astronomer.
Supernovas are particularly fascinating and active objects, as Tycho noted half a millennium ago. In 2019, Johan photographed the remains of another supernova, the Crab Nebula (Messier 1), the explosion of which was observed in the Middle Ages, on 4 July 1054, coincidentally or not the year of the Eastern Schism.
Tycho had already heard of the impoverished, but brilliant, 25-year-old Johannes Kepler, whom he invited to Prague. The titans discussed, bickered and worked together for a year, until Tycho died unexpectedly aged 55 (in 1601) and Kepler took his place. The latter, now more famous, developed Kepler's Laws, which describe planetary motions mathematically (but not physically, which Newton did in 1687).
In 2009, NASA launched the Kepler telescope, which observed thousands of exoplanets.
Back to the Moon before we move on: Tycho's crater briefly gained global attention in 1968 in full space-race: In the cult film "2001: A Space Odyssey", an iconic 'monolith' was buried in Tycho.
Blood Moon, Super Moon, Wolf Moon
Thanks to its movements and phases, and to the interplay of light and shadow, the Moon is an interesting and capricious cosmic rock that has fascinated mankind since time immemorial.
In January 2019, for example, Johan photographed a beautiful blood moon. Three events coincided: a supermoon (moon in the perigee, closer to Earth and therefore larger), a wolf moon (first full moon of the year among Native Americans), and a blood moon (in the Earth's shadow cone, tinting it red, the actual lunar eclipse).
Great conjunction, Milky Way and star clusters
Moving past our homely Moon-Earth system, Johan pointed the telescope toward gas giants Jupiter and Saturn, which could be seen in conjunction at Christmas 2021, including their small moons, on which microbial life may have originated under thick ice sheets (the Juice mission is going to figure that out). I used the metaphor of the great conjunction of Jupiter and Saturn for the circumstances that led to my meeting with Jane Goodall.
Milky Way is easier to capture in a sparsely populated area than in overlit
Flanders, which is why Johan sometimes travels to France. The 2022 photo below
shows a piece of our home galaxy.
Back in Belgium, Johan focusses the telescope on individual objects in space. A star cluster is always a beautiful sight, such as the Hercules globular cluster (see photo below) with about a hundred thousand stars; also known as M13 (Messier 13). The stars in a cluster are gravitationally anchored to each other, and are much closer together than the sun and nearby stars, sometimes leading to smashing interactions.
A gold medal, the Pleiades and distant galaxies.
M in M13 and others refers to Messier object, named after the French astronomer Charles
Messier (1730-1817) who catalogued about a hundred nebulae and star clusters
when he was actually looking for comets. But star clusters themselves were
first described as such by William Herschel (1738-1822), a German musician who
moved to England and began studying mathematics and astronomy. He
single-handedly built one of the then strongest and largest telescopes. His
sister Caroline Herschel, then less well known as a woman, assisted him in all
his whims and grew into a full-fledged astronomer too. She discovered several
comets and in 1828, when she was elderly, received the Gold Medal of the Royal
Astronomical Society. It would be another 168 years after that (until 1996)
before this honor was bestowed upon a woman again (Vera Rubin).
A quick sweep through the Milky Way: The photogenic reddish Horsehead Nebula appears in the constellation Orion. The brightest star near the Horsehead is Alnitak, in Orion's Belt. The blueish Pleiades or the Seven Sisters, in Taurus, also make for stunning images.
following pictures show some galaxies, with Johan looking beyond the Milky Way.
In the Whirlpool Nebula (M51), we see how two galaxies interact. Bode's Galaxy
(M81) is a bright galaxy with a supermassive black hole at its center. The
Andromeda Nebula (M31), the most famous of all nebulae, is the farthest object that
can be seen with the naked eye.
One last anecdote about citizen science and amateur astronomy. The Leonids meteorite swarm (in Leo), produces very intense fire rains every 33 years in November. Almost two hundred years ago, they gave rise to one of the first calls for citizen science: On Nov. 13, 1833, as many as ten thousand shooting stars could be seen per minute. Yale mathematician Denison Olmsted was so impressed that he put out a call in the newspaper, asking citizens to describe the fiery shower with as much precision as possible. Relying on the incoming data, Olmsted was able to show that meteorites have a cosmic origin and were not a weather phenomenon (as the name meteorite suggests), as was still believed at the time.
Even today, every citizen can participate in various astronomy projects, directed from astronomical societies such as Urania of which Johan is a member, and many projects at space agencies. So much for this fleeting glimpse from his archives. Who knows what pictures he will take next with the new telescope he is about to install.
If you got as far as here, you'll definitely also like the Exoplanets article, about how many planets exist outside the solar system, and how people look for water and life beyond the Solar System, and what "habitable" really means. The origin of the Moon was one of my first articles. To my relief, scientists still haven't fully figured out how the moon came to be, even though they agree on the broad outlines. Did lightning supply phosphorus to ancient life? That also prompts some thinking, about how life arose and which cosmic elements were or were not essential.
Maria Popova, 2020, Figuring. Cannongate Books. (levenslopen en interacties van historische wetenschappers, vooral minderbekende studiosi en vrouwen).
Maria Popova, 2021, The Marginalian, Citizen Science, the Cosmos, and the Meaning of Life: How the Comet That Might One Day Destroy Us Gives Us the Most Transcendent Celestial Spectacle.
Space objects facts: Wikipedia.
Kathelijne: As a nature lover and earth scientist I am intrigued by how life, air, rocks, soil, ocean and societies interact on geological and human timescales.
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