The Planetarium Shines Again
On 28 March 2026, the school planetarium at Albert-Schweitzer-Oberschule in Chemnitz reopened after nearly a year of closure. A packed house, an uncooperative sky, and the clear sense that this place had been missed.
Writing & process
On 28 March 2026, the school planetarium at Albert-Schweitzer-Oberschule in Chemnitz reopened after nearly a year of closure. A packed house, an uncooperative sky, and the clear sense that this place had been missed.
The planetarium at Albert-Schweitzer-Oberschule Chemnitz is restarting. Join us for the Tag der Astronomie on 28 March 2026 – free planetarium shows, telescopes, and live views through the observatory. No registration required.
Skywarden and Theo are free and will stay that way. Here's what that means in practice — and why I ruled out every other option.
Skywarden gained support for detailed horizon profiles - but creating one required either expensive surveying hardware or apps that cost €20–30 for a task most astrophotographers do once or twice. So I built Theo: a free PWA that uses your phone's sensors and camera to capture azimuth/altitude pairs around the full 360° and export them as a .hrz file. This is the story of why it exists, how the sensor math works, and where it fits into the Skywarden workflow.
I spent some days on Codex after hitting Claude's limits. Then the Pentagon deal happened – and Anthropic said no while OpenAI said yes. Here's why I switched back.
After a month of building Skywarden with Claude Code, I've come to see AI-assisted development not as a replacement for good engineering - but as the next evolution of it.
My astrophotography planning tool is growing up. Rebranding from Astro Planner to Skywarden, the app now features deep weather integration with safety alerts, a year-ahead planning mode with calendar exports, and dedicated presets for smart telescopes. Stop guessing what to shoot and start guarding your clear skies.
Astro Planner is an astrophotography planning tool that recommends deep-sky targets based on your setup, location, and sky conditions.
On the night of Jan 19 - 20, the strongest aurora I’ve seen so far lit up the sky in vivid green, pink, and violet. Driven by an X1.9 solar flare and an Earth-directed CME, geomagnetic activity surged beyond Kp 8,67 (G4 on NOAA’s scale) and the main show peaked between 21:45 and 23:30. With a new-moon darkness and clear, cold air, the green curtains were even visible to the naked eye - and I ended up capturing it all on my iPhone because my camera wasn’t charged.
After two failed attempts — one drowned by rain and another cooked by dew — I set out to build a smarter, more resilient allsky camera. This post shares how I created a waterproof 3D-printed housing, automated dome heating with weather-based control, and learned a few lessons about balancing hardware, software, and patience along the way.
While I follow the development of AI with a lot of interest, I do not want my work to be used for training these models. I just learned that it's possible to (at least try to) block AI bots from crawling a website using the robots.txt file.
Yay, my composite image of the Lunar Eclipse above the Lulatsch in Chemnitz was just selected as a "Top Pick" on Astrobin 🎉
The final morning brought a peaceful end to a weekend full of astronomy and friendship. After a much quieter night free from mosquitoes, I found myself both eager and reluctant to pack up our gear. Reviewing the night’s images while still half-asleep, I was grateful to see the skies had cleared and allowed for some last-minute shots of the Bubble Nebula. Saying goodbye to Ronald and the new friends we had made was bittersweet; these connections beyond the telescopes gave the event a special warmth. As we headed home to Chemnitz, I carried with me the joy of a weekend well spent under the stars, knowing that next year, we would return to Jeßnigk to do it all over again.
This Saturday at the Herzberger Teleskoptreffen was a mix of challenges and unforgettable moments: from a restless mosquito-filled night to breathtaking views of the sun through H-alpha telescopes, and the peaceful charm of Jeßnigk’s village life. Despite weather hurdles and technical setbacks, the experience deepened my passion for astrophotography and stargazing, reminding me that each night under the stars holds its own unique magic — sometimes quiet and clear, sometimes clouded, but always inspiring.
In pursuit of a long-awaited father-son road trip, I found myself racing daylight to the Herzberger Teleskoptreffen — our van packed with excitement, telescopes, and hope for clear skies. As we set up camp beside familiar faces and under a darkening Brandenburg sky, a sense of adventure took over. With the Milky Way shimmering overhead and the thrill of finally capturing Sh2-132, the night blended my passion for astrophotography with precious moments shared with my son — complete with laughter, starlight, and a few stubborn mosquitoes.
Recently, I set out on a personal quest to find an art gallery willing to showcase my images - a journey filled with both anticipation and challenges.
For TUC Tag 2025, a friend and me did an astronomy roadshow at TU Chemnitz, exhibiting our photography, explaining telescopes and doing some live astronomy.
For one year now, we're mobile fully electric with our Volkswagen ID.Buzz and Renault Zoe - a look back.
An artistic view on our moon passing in front of the pleiades.
Featuring a dramatic view on our moon surrounded by beautiful stars.
The year is coming to an end and I want to take a look back at what I achieved.
The year is coming to an end and I want to take a look back at what I achieved.
For the first time, I'm offering my best photographs in a beautiful wall calendar. Available in two sizes. Get yours now!
To celebrate the latest capture of the object, that started it all for me, the great Orion nebula, I'm taking a look back and showcase a few milestones on my astrophotography journey so far.
The year is coming to an end and I want to take a look back at what I achieved.
This is my first time witnessing an aurora
Hello World! Beware, I decided to blog again.