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Thirty Years of the Square Kilometre Array

72 points by mooreds

by marbs

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If you drive from Cambridge (UK) to Wimpole, you'll see some impressively large radio telescopes that belong to the Mullard Radio Astronomy Observatory (MRAO).
However, there's much more that's not visible from the road. Hidden behind the trees, MRAO has a prototype SKA-Low array (from before the full installation in Australia), and three dishes from a HERA prototype.
The MRAO itself has a fascinating history, notably including the discovery of the first pulsar by Jocelyn Bell using the wonderfully named Interplanetary Scintillation Array, which consisted of over four thousand dipole antennas spread across nine acres. In WWI the site was a mustard gas factory, with train station and sidings. The train tracks have long since gone, but the station building remains. Inside hangs a large, coloured but faded image titled "GALACTIC RADIO EMISSION AT 38 Mc/s". This appears to be a coloured visualisation based upon the black & white figure in pages 654-655 of a 1957 paper [0].
The above 1957 paper illustrates a survey of half the celestial sphere at 38 MHz. In comparison, this specific MeerKAT image from the article [1] appears to be a 1.28 GHz measurement focusing on the galactic center (6.5 square degrees) [2]. So it's not a 100% like-for-like comparison, but interesting nonetheless to see how much the detail has improved in the past ~70 years!
[0] https://adsabs.harvard.edu/pdf/1957MNRAS.117..652B ("RESULTS OF A SURVEY OF GALACTIC RADIATION AT 38 Mc/s")
[1] https://physicsworld.com/wp-content/uploads/2025/03/2025-02-...
[2] https://arxiv.org/pdf/2201.10541 ("The 1.28 GHz MeerKAT Galactic Center Mosaic")

by beastman82

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> The image (above) shows long radio-emitting filaments up to 150 light–years long unspooling from the heart of the galaxy. These structures, whose origin remains unknown, were first observed in 1984, but the new image revealed 10 times more than had ever been seen before.
I don't understand how this isn't the biggest news in astronomy. Gigantic filaments of energy passing through the milky way

by dylan604

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Do these interferometer type of arrays attempt to have the dishes at the same level essentially a flat plane? Or can they adjust for that with the timing used to "sync" them together so one dish might be in a dip while another is higher on a mound. TFA mentions 150km diameter array. Does the earth's curvature come into play as well?

by qwertytyyuu

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I love physics names. A array of telescopes with collecting are of 1 square kilomter. Square kilometer array. Makes it so clear what it is.

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by JamesTRexx

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"Makes it so clear what it is."
Well.., I've been more busy with writing code lately so that the first question coming to mind was, how many bytes is an array of one square kilometer? And I assume it's a two-dimensional array.