Visor on the sun on National Solar Observing Day

Photo above:
While the public has the chance to see the sun up close through the telescopes, Nicolàs and his colleagues explain. Photo: Henk from Reus

Castricum – Last Sunday was National Sun Observation Day. It was a unique opportunity to see the sun up close and observe its activities. This was possible in associations and public observatories, but also at the private observatory of the amateur astronomer Nicolàs de Hilster on the Oude Haarlemmerweg.

By Henk de Reus

Even before the visit arrives, Nicolàs de Hilster looks at the clouds in the sky. ,,No clear blue sky today, but better than rain.” 28 people pre-registered for the show. Nicolàs has divided them into small groups and uses time slots to give everyone enough attention. In his garden are three huge telescopes pointed at the sun. Three colleagues – Rob, Caspar and Roman – tell visitors what they see.

cloud for the sun

Meindert Kuipers (63) has been interested in everything related to space since his childhood. “I bought my first twins when I was fifteen. I’ve always found it fascinating that you can see special things with binoculars that you can’t observe with the naked eye. The binoculars have now given way to a 90 millimeter telescope. ,,With the sun it’s hard to catch it with my telescope, but here it works fine.” As he says that, a cloud passes right in front of the sun.

Stains and flames

Nicolàs takes Meindert to his observatory, two floors above. This dome contains a Galilei telescope, a SkyWatcher Esprit 150 ED, a Lunt LS80THA and a Celestron C11 EdgeHD. Enough material to see details of the sun, such as sunspots and solar flares. Nicolàs explains that sunspots are disturbances in the magnetic fields of the sun. They are often larger than the Earth. At this location, the sun is 1000 to 1500 degrees cooler than the rest of the sun, where the average temperature is 5500 degrees. Solar flares are located at the edges of the sun. These are flares on the sun, also caused by disturbances in the magnetic field. The sun spits out energy, which is often pulled away by the sun’s gravity. But sometimes it disappears into space. According to management, these will meet at our poles. This is how the Northern Lights can be created.”

Fascination

Max Zonneveld (10) has just arrived with his grandfather Frank Husslage. His T-shirt bears the NASA logo. His interest in space started very early. He finds the mysterious aspect in particular fascinating. Max received a telescope for his birthday, but he doesn’t understand much about it. “If I put on a filter and point my telescope at the sun, all I see is a black field.” One of the passers-by responds with “Maybe you can see black holes with your telescope.” Max doesn’t like the joke. Grandfather Frank calls home and a little later Max’s father arrives with his son’s astronomer. One of Nicolàs’ assistants examines it and solves the problem. Max happy. The sun rises again for him.

There is still a little time before April 2024. Then most activity is expected on the sun and… maybe we will see the Northern Lights again here.