Calar Alto brings the solar eclipse to your home

The Calar Alto Observatory and the Azimuth science outreach team will offer a live, commented and completely free online broadcast so that everyone can enjoy the opportunity to watch this astronomical event. Calar Alto brings the eclipse to your home!

Online broadcast of the solar eclipse

• Format: online, live, commented and completely free
• Location: Calar Alto Observatory
• Setting: Calar Alto’s professional 1.23m telescope
• Participation: live comments, questions and queries

An eclipse to bring astronomy closer to everyone

The Calar Alto Observatory and the Azimuth science outreach team will offer a live, commented and completely free online broadcast so that everyone can enjoy the opportunity to watch this astronomical event. Calar Alto brings the eclipse to your home!

We want to take advantage of this solar eclipse, an exceptional astronomical event in every sense, to bring science and astronomy closer to the public, providing throughout the event the key information needed to understand and interpret how this astronomical phenomenon works.

From inside the 1.23m telescope

To do justice to such an exceptional occasion, we have chosen to place the equipment that will allow us to follow the eclipse next to Calar Alto’s professional 1.23 m telescope, making this the only eclipse broadcast in the world carried out from inside a telescope used for scientific research. The setting could not be more astronomical!

Accessible and participatory astronomy

We also want the event to feel very close to everyone, and for this reason we have decided to follow the eclipse using telescopes and instruments within reach of any amateur astronomer. This is technology that we can simply use to enjoy observing the Universe as amateurs, or to go one step further and take part in citizen science projects, thereby contributing to the advancement of scientific knowledge.

As for the equipment, we will have a varied selection of instruments, allowing us to view the eclipse in different ways and making the broadcast a dynamic event that truly illustrates what we can achieve with our own resources as amateur astronomers.

The Sun in H-alpha

Let us begin the overview of the equipment with the most distinctive item: we will use one of the telescopes known as H-alpha telescopes, named after the wavelength that characterizes the region of the Sun known as the chromosphere. This is where such striking phenomena as protuberances or prominences take place: enormous magnetic fields that drag solar plasma across linear distances equivalent to tens of Earth diameters. While observing the eclipse using this very particular radiation, we will also have the opportunity to observe other typical chromospheric phenomena, such as granulation, or active regions where solar magnetic activity is most intensely concentrated.

Photosphere, camera and view of the dome

We will also use a camera body, which we will alternately attach to two different lenses. On one hand, we will use a telephoto lens equipped to observe the solar photosphere—the region of the Sun that allows us to see its true appearance in visible light, and to verify that the Sun is actually whitish in color, and not yellow or orange, due to the effect of atmospheric extinction. In the photosphere we will have the opportunity to observe the famous sunspots, if any are present, or faculae, regions where the intensification of the magnetic field raises the temperature and gives the facula the appearance of a “filament brighter than the surrounding regions”.

Alternatively, we will detach the camera body from the telephoto lens and install it on a wide-angle lens. Working as a fixed camera, it will allow us to see the inside of the dome building, with the 1.23m telescope and the set of mounts, telescopes, cameras and computers that will make it possible to generate the different signals and broadcast them online in real time.

A participatory broadcast

And finally, the most important part of the whole setup: we want you to be part of it! The social media and communication teams from both the Calar Alto Observatory and Azimuth will be waiting for your live comments, questions and queries, so that this broadcast becomes an interactive and participatory event and allows us to share this wonderful experience that nature offers us.

Important notice

Access to the observatory will remain restricted throughout the week for safety reasons (eclipse and Perseids).

Please do not go up to the area and always follow the instructions of the staff and authorities.