Dual sites for SKA announced 2/3 Africa, 1/3 Australia

Dense Aperture Array

The Square Kilometre Array announcement has finally come out. And it is a split decision as predicted - partially at the African MeerKAT site, and partially at the Australian ASKAP site, as explained in the official release:

The ASKAP and MeerKAT precursor dishes will be incorporated into Phase I of the SKA which will deliver more science and will maximise on investments already made by both Australia and South Africa.

The majority of the members were in favour of a dual-site implementation model for SKA. The members noted the report from the SKA Site Advisory Committee that both sites were well suited to hosting the SKA and that the report provided justification for the relative advantages and disadvantages of both locations, but that they identified Southern Africa as the preferred site. The members also received advice from the working group set up to look at dual site options.

Spare Aperture Array

The majority of SKA dishes in Phase 1 will be built in South Africa, combined with MeerKAT. Further SKA dishes will be added to the ASKAP array in Australia. All the dishes and the mid frequency aperture arrays for Phase II of the SKA will be built in Southern Africa while the low frequency aperture array antennas for Phase I and II will be built in Australia / New Zealand.

Some of the dishes already built in the
Murchison desert in West Australia

So essentially the low frequency aerials will be built in Australian and NZ and the higher frequency dishes in Africa, although additional dishes will also be built at ASKAP - thereby extending its baseline by thousands of kilometres.

The Twitterverse promptly went crazy following the announcement, which coincided with the berthing of the SpaceX Dragon capsule with the international Space Station.

One of the astronomers involved with the Australian bid Lisa Harvey-Smith (@lisaharveysmith) tweeted:

A great result for all radio astronomers. I look forward to discovering the mysteries of the universe together!

Another Bryan Gaensler ‏(@SciBry):

SKA telescope board made right decision to split site. Maximises strengths of both sites, minimises risks. Let's build it - I want data!

Australia's Nobel Prize winner Brian Schmidt (@cosmicpinot) summarised the outcome:

Majority Phase 1 will be built in South Africa, combined with MeerKAT. Further SKA dishes will be added to the ASKAP array in Australia. Dishes & mid frequency aperture arrays for Phase II Southern Africa - low frequency aperture array antennas for Phase I & II in Australia. Phase I SKA split decision makes lots of sense-existing infrastructure sufficient. I worry about money for Phase II. Glad we have a decision.

The African SKA twitter account put it more succinctly:

@SKA_Africa: Minister Pandor is clear: 2/3 of antennae technologies will be built in Africa. 1/3 built in Aus&NZ.

BBC science reporter Pallab Ghosh (@bbcpallab) was less gracious:

My view? Africa big winner #ska. AUS/NZ thrown a bone. Split site enables little more science and more cost.

I tend to think that the committee recognised the threats facing the African sites and the quality of the interference-free site of the Australian bid. Placing some of the project in Australia recognises that the better science will come from here. But politics decreed a need for the governing countries to throw their support behind Africa's bid. There are values beyond the science, so it is fair enough to accommodate them too.

Now - on with the actual project!

UPDATE:

Lisa Harvey-Smith has been quick off the mark with this explanation of the decision and what it means for Australia. It includes a video clip of her talking about the project.

FURTHER UPDATE:

Bryan Gaensler has also written about the decision, with further points about why the outcome is good for everyone, and certain no "thrown bone", as Ghosh portrayed. Some key points:

What the SKA board has decided is to put different technologies in different places, playing to the strengths of each site. The lowest frequency component, consisting of antennas that do not move or steer and that can collect signals from the whole sky at once, will be built in Australia and New Zealand.
This capitalises on the superb “radio quietness” of the SKA core planned for Murchison in outback Western Australia – one of the few places on the planet that isn’t polluted by FM radio and other artificial signals in this low-frequency band.

The remaining pieces of the puzzle are “phased array feeds”, the fish-eye lens technology being developed by CSIRO for their Australian SKA Pathfinder (ASKAP) in Western Australia.
This technology will be further developed and expanded in Australia and New Zealand, and then possibly later installed on dishes in Africa. Australian and New Zealand technology on an African telescope truly is a win-win scenario.