Observing the Sun with a professional telescope at Galáctica

Galáctica's astronomy is also done in broad daylight. On Saturdays and Sundays, depending on the time of year, a guide shows you the Sun through a professional solar telescope, with free admission to the museum included. It is the activity for those who can't stay for the night, for those with children who are exhausted by eight o'clock or for those who want to round out the afternoon before the night observation.

From the talk to the eyepiece

At the time you chose when booking, the guide gives a short talk inside the building about the Sun: what it is like inside, how it produces its light, what it is made of and how big it is. Then you go outside and look at the star through the telescope. What you are looking for are the outer layers: spicules, spots, filaments and prominences, those arcs of gas that peek over the edge of the disc. Before or after, you walk round the museum at your own pace. Galáctica estimates between one and two and a half hours for everything, depending on how long you linger in the rooms.

The GT Solar+, a refractor with a narrow-band filter

The instrument is a 150 mm apochromatic refractor with a fast 2048 × 2048 pixel camera, which can photograph the whole disc or a third of it at higher magnification. It has a Fabry-Perot etalon, a filter that lets through only a very thin band of light: the hydrogen H-alpha line or the calcium H and K lines. That way you see the chromosphere, the layer where prominences are born, which an ordinary telescope doesn't show. Looking at the Sun without a filter of this type damages your eyesight irreversibly: here the guide controls the instrument.

€28 with the museum included

€28 per adult, €23 for children up to age 10 and free for under-4s, with free admission to the museum included. Galáctica sets no minimum age and says the solar observations suit all ages, with the content adapted to the group. In the website's shop, the listing asks you to first add a museum ticket to the basket; check the total before paying. The times for each Saturday and Sunday appear when you choose the date.

If the day turns out cloudy

Without the Sun there is no observation. For the night ones, Galáctica warns 48 hours ahead if the forecast is bad and cancels at 24 hours with a voucher or an indoor plan; the solar listing does not say whether the same applies. Its general conditions only refund the money when the service cannot be provided for reasons beyond the visitor's control. If you see clouds in the forecast, call 613 291 772 first.