As you know now, in radio astronomy we study objects in the sky by catching radio waves. But what does that exactly mean? And what do radio astronomers see when they look at the sky? We will tell you all about that here.

Different types of radiation

You know now that there are different types of radiation which can be seen at different frequencies. Each radiation can be seen with different types of telescopes. Radio astronomers can look at different elements depending on the wavelengths they attempt to receive. If they study the same objects using different wavelengths, they will obtain images very different one from another, allowing different analyses.

In the image below you can see the different types of radiation (© NASA).

types of radiation

Crab Nevel

In the picture below, you see the Crab Nevel in different types of radiation. The Crab Nevel exploded 1000 years ago as a supernova. This was observed by the Chinese and was one of the first reports of a supernova. This nebula is about 6500 lightyears from Earth. As you can see the shape of the nebula is different in each type of radiation. You can also see different types of structures in the nebula. This gives us a lot of information about what is in the nebula.

Crab Nevel

Andromeda Galaxy

In the image below you see an image of the Andromeda Galaxy, also in different types of radiation. From the top left to the bottom right you see: Radio, far infrared, near-infrared, visible, ultra-violet and X-ray light.

Andromeda Galaxy

Cygnus A

Some galaxies were discovered in radio light first, such as Cygnus A (in the constellation of Swan, the strongest radio source, and one of the strongest sources in the sky). At high frequencies, we see a small dot in the middle, with two huge rays that end in some kind of dumbbell. This is not light as it is made in the sun (nuclear fusion), but light that arises because matter moves enormously fast in a magnetic field. This intensity can only occur if there is a black hole at the base.

Cygnus A

Latest tweets

Another great achievement by @ehtelescope! Our new director @astroTui was involved as well, as a member of the #EHT team.

Every year on 4 May at 8 pm, our Westerbork telescope goes into a special mourning position to commemorate those who have fought for our freedom. This video, made together with @kampwesterbork, shows the dishes moving into position.
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Our 'holy grail' has been found again! The #Kootwijk dish, which stood at the origin of ASTRON, has been located at @museumdeelen! The dish, originally a #Würzburg-Riese German radar dish, was the second telescope ever to detect the #hydrogen line.

Issue 10 of @SKAO's Contact Magazine has been published, featuring 3 articles related to ASTRON: 1 about our new director @astroTui, 1 about @LOFAR's massive data release, and 1 by our own @tammojan about @LOFAR imaging radio emissions of meteor showers.