Retro Programming Nostalgia: quando l’Amiga 500 calcolava le cariche atomiche

Un programma in GFA BASIC, il metodo di Gasteiger–Marsili e un ricordo della mia tesi di laurea in Chimica.

All’epoca della ricerca per il mio progetto di laurea in chimica, ero ancora un entusiasta possessore dell’Amiga 500. Il kernel del Linux OS era stato appena ufficialmente rilasciato nella versione 0.01 da Linus Torvalds, e la distribuzione Slackware sarebbe stata rilasciata nel luglio del 1993. Come descritto nel mio articolo sulla mia tesi di laurea, all’epoca l’Apple Macintosh per scrivere la tesi e il mainframe IBM 3090 per i calcoli. Il mio primo PC lo acquistai durante il mio dottorato di ricerca con l’idea di installarlo con Linux in dual boot con MS Windows. All’epoca conoscevo bene il BASIC disponibile sui vari microcomputer che ho avuto (vedi i miei articoli sul retrocomputing) e l’Amiga Basic del mio Amiga 500 che acquistai durante i miei primi anni universitari. Quando iniziai la mia tesi di laurea, cominciai a imparare a programmare in FORTRAN 77, linguaggio usato per scrivere i codici per le simulazioni di dinamica molecolare. Continui limitatamente ad usare anche il mio Amiga 500 per la grafica e la programmazione.

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The Runge–Kutta Integration Method: Returning to the Moon After 50 Years (Part II)

This is the second article in a series introducing numerical methods for solving differential equations, inspired by one of humanity’s greatest technological achievements: the journey to the Moon.

In July 2019, I wrote the Italian version of this article to celebrate the 50th anniversary of the Apollo 11 mission. On 20 July 1969, Neil Armstrong and Edwin “Buzz” Aldrin became the first humans to walk on the lunar surface, while Michael Collins remained in lunar orbit aboard the Command Module Columbia.

More than half a century later, the Moon continues to inspire scientists, engineers, and explorers. NASA’s Artemis programme, together with initiatives from other space agencies and private companies, represents a renewed effort to explore our nearest celestial neighbour. In 2026, the Artemis II mission marked another milestone with a crewed journey around the Moon, recalling the historic flight of Apollo 8 in 1968. These developments renewed my interest in the mathematical and computational techniques that made the Apollo missions possible. How could the computers of the 1960s, with their extremely limited memory and processing power, calculate the trajectories necessary to navigate between the Earth and the Moon?

To explore this question, I returned to historical NASA documentation and the scientific literature on numerical integration. In this article, I summarise some of these findings and introduce the Runge–Kutta method, one of the most widely used techniques for solving differential equations numerically. As usual, I will also include a simple computer program to illustrate how these mathematical ideas can be put into practice.

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Solar Eclipse 12 August 2026 from Lincoln, UK | Telescope, Environmental Data & JPL Simulation

Just a few days ago, I was lucky enough to witness, with my own eyes (safely protected by a proper solar filter!), one of the most fascinating astronomical events visible from Earth: a solar eclipse. Eclipses are not particularly rare on a global scale, but their visibility strongly depends on geographical location. The path of a total solar eclipse covers only a relatively narrow region of the Earth’s surface, meaning that totality may return to the same location only after a very long interval. Solar eclipses have fascinated humans for thousands of years and are among the astronomical phenomena most extensively recorded by ancient civilizations. Historical observations from Babylon, China, Europe, and the Arab world are so valuable that they have even been used to investigate changes in the Earth’s rotation over the past several thousand years.

On 12 August 2026, a total solar eclipse crossed parts of the Northern Hemisphere. From the UK, where I currently live, totality was not visible, but a substantial partial eclipse could still be observed. Having a basic refractor telescope and a good observation point, I decided to try recording the entire event as a time-lapse. I invested in a suitable solar filter for my Bresser Arcturus 60/700 mm telescope. The telescope has no automatic tracking, so this meant manually following the Sun throughout the roughly two-hour event. Afterwards, I planned to use Python, computer vision, and ChatGPT to align and filter the recorded frames and reconstruct a smooth eclipse sequence.

But my interest in this event was not limited to photographic observation. I was also curious to extract quantitative information from the recorded frames and to investigate what was happening to the environment while the Moon progressively obscured the Sun. Changes in incoming solar radiation should affect quantities such as light intensity, UV radiation, and, potentially, temperature and humidity. I already had several Arduino boards and a collection of inexpensive sensors at home, so this seemed like a perfect opportunity to turn the eclipse observation into a broader experiment. The question behind the project therefore became: Could a simple telescope, a few low-cost sensors, and some Python code reveal not only the progress of a solar eclipse, but also how the environment responds to it? The answer was YES: it is possible, and it was pretty simple to set it up!

I have published an article on my Instructables website in which I outline the setup of my Environmental Solar Station (ESS), show what I measured during the eclipse, and suggest ideas for future development. In this post, I will instead give some information about the creation of the video on the YouTube channel embedded below.

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Rediscovering Halometry with Raspberry Pi and Laser Diffraction

One of the aspects of experimental science that I find most fascinating is the rediscovery of historical scientific instruments and techniques that have gradually disappeared from modern laboratories. In my latest Instructable project, I explored the reconstruction of a remarkable optical device once used in hematology during the early twentieth century: the halometer.

Before the advent of automated blood analyzers and digital microscopy, researchers investigated ingenious indirect methods for estimating the average size of red blood cells. One of these methods relied on diffraction phenomena produced when coherent light passed through thin blood smears. The resulting circular halos could be related to the average diameter of erythrocytes, providing a rapid—although approximate—diagnostic technique for conditions such as pernicious anemia.

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Retro Programming Nostalgia VII: lo Studio di Funzioni

Continua l’esplorazione archeoinformatica dei miei programmi in linguaggio BASIC sviluppati negli anni ’80 e ’90 su homecomputer di quell’epoca. Questa volta voglio raccontarvi di un programmino sviluppato per il microcomputer MSX1 Phillips VG8010 (commercializzato dalla Phillips nel 1984) durante gli ultimi anni di liceo e adattato successivamente al BASIC del mio primo e mitico calcolatore programmabile, il Texas Instruments TI-74 (la figura mostra il mio TI-74 tuttora ancora funzionante), durante i primi anni universitari.

Il programma fu sviluppato con l’intento didattico di analizzare delle funzioni a una variabile in un intervallo definito dall’utente per poter rappresentare la funzione, le sue derivate e l’integrale graficamente, nonché individuarne numericamente le caratteristiche principali, quali le posizioni degli zeri, dei punti estremi e quelli di flesso.

Non avendo delle basi di analisi numerica, gli algoritmi numerici usati per queste analisi non erano molto sofisticati ed erano ispirati a rubriche lette sulla rivista più autorevole di cultura informatica italiana MC-Microcomputer di cui ero un assiduo lettore.

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Educational 3D Reconstruction with the RasPi MilliTome

I’m happy to share my latest project, “The RasPi MilliTome: A Manual Sand Slicer for 3D Reconstruction,” which has just been published on Instructables — and even more exciting, it has been featured by their editorial team in the Teachers Section.

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Ettore Majorana e L’Equazione di Fermi-Thomas

Perché al mondo vi sono varie categorie di scienziati, gente di secondo e terzo rango, che fa del suo meglio ma non va lontano; c’è anche gente di primo rango, che arriva a scoperte di grande importanza, fondamentali per lo sviluppo della scienza. Ma poi ci sono i geni, come Galileo e Newton. Ebbene Ettore era uno di quelli. (Commento di Enrico Fermi alla notizia della scomparsa di Majorana)

Qualche tempo fa ho rivisto il film su Raiplay in due parti diretto da Gianni Amelio, I ragazzi di via Panisperna. Si tratta di un’opera trasmessa dalla Rai alla fine degli anni Ottanta, molto bella e ben realizzata, che racconta le vicende che portarono alla formazione, negli anni Venti e Trenta, del celebre gruppo di Enrico Fermi presso l’Istituto di Fisica di via Panisperna, all’Università di Roma. Il film si concentra in particolare sulle figure di Ettore Majorana (interpretato da Andrea Prodan) e di Enrico Fermi (Ennio Fantastichini).

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Easter 2026: The Patterns on Coturnix Egg

Last year, after a series of unsuccessful attempts and acquiring three incubators across two countries, my youngest son’s unwavering determination finally paid off.  From a batch of twelve mixed quail eggs, seven hatched successfully, marking the start of our new venture into farm animal husbandry.  Currently, we’ve settled for manageable pets like a Siberian hamster, an aquarium, and pond fish, plus several rounds of stick insects, mantises, and spiders, along with their grasshopper and locust food supplies.  However, quail care is more demanding. While our sons’ happiness is undoubtedly the most important reward, the delicious eggs produced by our farm breeding activity are equally rewarding for the whole family.  It’s particularly satisfying collecting every evening the two expected eggs from the punctual quail hens and admiring their different sizes and pigmentation like beautiful little gems.

If you’re still reading, you’ve probably guessed the main topics of my traditional Easter blog: quail eggs and their shapes and patterns.

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The Numerical Solution of Differential Equation using the Shooting Method

Boundary value problems (BVPs) for ordinary differential equations arise naturally in many areas of physics, engineering, and applied mathematics. Classic examples include the vibration of strings, heat conduction in solids, and quantum mechanical bound states. Unlike initial value problems (IVPs), where all conditions are specified at a single point, BVPs impose constraints at different points of the domain, making them significantly more challenging to solve both analytically and numerically.

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The Smoluchowski Diffusion Equation

The Smoluchowski diffusion equation describes the time evolution of the probability density function (PDF) of a particle undergoing overdamped Brownian motion in a potential energy landscape. It is a central equation in statistical mechanics, soft matter physics, and chemical physics.

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