Russia finally launched its giant radio telescope, the Spektr-R, into space using a Zenit rocket from the Baikonur Cosmodrome in Kazakhastan on the 18th July. No word about the operational status has been officially released.
The planned elliptic orbit has a perigee of 1000 km and apogee of 330,000 km. The observatory holds a giant 10 meter wide antenna and is expected to be a part of the International Radioastron Astronomy Project. The Astro Space Center of Moscow, a part of the Lebedev Physical Institute of the Russian Academy of Sciences, is coordinating the Radioastron mission. The project is a focal point of international co-operation with 20 nations contributing to it, including the United States.
Tricks up its giant sleeve
The claim to fame of this giant telescope is the facility of interferometry using ground based radio telescopes. In size, it is less than a tenth of the largest radio telescopes on Earth, but due to a technique called interferometry’, the telescope is expected to give resolution higher than Hubble in the radio frequencies.
Radio telescopes are laid out in a particular fashion on a wide area. They separately capture radio waves and then transmit this signal to a central computer, which adjusts for time delays and forms a coherent picture of what the entire field is seeing. This is done by adding’ or interfering’ the differing signals; thus the technique is called interferometry’.
Radio telescopes have another trick up their sleeve a Nobel Prize winning trick. They use the Earth’s rotation in increasing their effective aperture. Signals from a radio source are sampled from different baseline orientations that change as the Earth rotates. This data is then fed into a computer, which uses Fourier analysis in order to obtain information equivalent to a conventional telescope with the equivalent large aperture. This is what gives the name Aperture Synthesis’.
Radioastron will be hoping to use interference with numerous ground based telescopes in order to create a giant effective telescope. It hopes to have a resolution of 7 microarcseconds, which is more than 10,000 times the resolution of the Hubble Space Telescope. On the list of things that Radioastron plans to look at, is a black hole in the center of galaxy M87 (or Virgo A) and different pulsars.
Though this is not the first attempt at earth-space telescope interferometry the Japanese attempted such a thing with HALCA, 15 years ago this is certainly the biggest. This one blows even Hubble out of the water.