The Russian Hubble?

Article written: 4 Aug , 2011
Updated: 24 Dec , 2015
by

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This is hardly breaking news, but there’s a new Russian space telescope in town. With a name like an anime character, Spektr R was launched on 18 July 2011 and its 10 metre carbon fibre dish was deployed a week later. It’s a radio telescope and – via a very large baseline array project known as RadioAstron – it will become arguably the world’s biggest radio telescope – and by a very long shot.

Following so closely after the Space Shuttle fleet’s retirement, the media has latched onto the idea that this represents a major step up from the Hubble Space Telescope and a further indication of the USA’s decline from space. But, nah…

Don’t get me wrong, when fully operational RadioAstron will be the biggest ever interferometer and is likely to deliver some great science when it gets up to speed. Well done, Roscosmos. But the various comparisons made between it and Hubble are a little spurious.

RadioAstron’s angular resolution is reported as 7 microarc seconds (or 0.000007 arcseconds) while Hubble’s resolution is generally reported as 0.05 arc seconds – so RadioAstron is reported as having over a thousand times more resolution. Well, sort of – but not really.

Firstly, the 10 metre radio mirror of Spektr R is designed to detect centimetre range wavelength light, while Hubble’s 2.4 metre mirror, is capable of detecting wavelengths in the visible light range of 350-790 nanometre range (and some non-visible infrared light too).

Angular resolution arises from the relationship between the wavelength of light you are observing and the size of your aperture. So, at the single instrument level Hubble rules supreme in the resolution stakes.

The image detail you can gain from arraying radio telescopes. Blobby false colour becomes more detailed blobby false colour (but there's useful science data there). Credit: VSOP.

The resolution assigned to RadioAstron (the telescope array) arises from the ‘virtual’ dish diameter created by Spektr R’s orbit, when arrayed with ground-based radio telescopes – which may eventually include Earth’s largest dish, the 300 metre Arecibo dish and Earth’s largest steerable dish, the 110 metre Greenbank radio telescope.

Spektr R will orbit the Earth via a highly elliptical orbit with a perigee of 10,000 kilometres and an apogee of 390,000 kilometres – so giving an elliptical orbit with a semi-major axis of 200,000 kilometres. That sounds like one big dish, huh… although it isn’t, really – just virtually.

Don’t get me wrong, there is a huge increase in information to be gained from arraying Spektr R’s one data point with other ground based observatories’ data points. But nonetheless, it is just radio light conveyed information – which just can’t deliver the level of detail that nanometre wavelength visible light can carry.

That’s why you can usefully create radio telescope arrays, but you can’t gain much value from arraying visible light telescopes (at least not yet). The information conveyed by radio light is spread widely enough so that you can estimate the information it is carrying from just detecting it at two widely spread detectors – and then superimposing that data. The fine detailed information contained in visible light is just too complex to allow this.

So putting up RadioAstron up as a contender to the beloved Hubble Space Telescope makes no sense. It is a totally different scientific project that will deliver totally different – and hopefully awesome – scientific data. Ad astra. If we want a step up from Hubble, we need to get the James Webb Space Telescope back into production.



32 Responses

  1. Philip Metzger says

    I detect a hint of jealousy by the americans (assuming you are) 😉

  2. Sounds more like a problem for James Bond.

  3. Anonymous says

    It’s quite a heavy beast: the scientific payload is 2.5 tons, and the total mass in orbit is somewhere about 3.5 tons. I wonder whether it would be possible to make a disk from something like the 60’s Echo balloons, but silvered on a dot on one side only. This could give you a huge dish for relatively little weight. The Echo 1-A balloon was 30 m in diameter, so the useful aperture would only be a fraction of this, but it only weighed 180 kg with solar cells and 1960’s transmitters.

  4. tommy skiens says

    Where and when can we see images generated by spektr R.

  5. Anonymous says

    Are there plans to eventually team this thing up with the SKA? Now THAT would be awesome.

  6. Anonymous says

    Are there plans to eventually team this thing up with the SKA? Now THAT would be awesome.

  7. This article is pathetic display of jealousy

  8. daniel--cunningham says

    That was the least scientific article I’ve ever read on this website. A biased article demeaning the achievements of a nation. The International Space Station was developed as a result of the wish for peace and collaboration to be part of the space program, this goes totally against that. A space telescope is a human achievement, not a competition. Whether “virtually” or a not, the resolution of what this space telescope will gather is much larger than Hubble’s. As for the wavelength of light… well, Hubble measured visual, ultraviolet, and near-infrared light. Those wavelengths ARE SMALLER than radio. Being a radio telescope, it is no surprise the wavelength of what this telescope will observe is larger.

  9. Anonymous says

    An array of Spektr type of radio dishes in space is needed. Of course just one in space does not factor in that much, but as the orbit goes out 10,000 km this does give a large baseline in one coordinate direction from which data can be analysed in a 1-d Fast Fourier Transform. We need two more of these, which will allow more triangulated data. If these could be placed at Lagrange points and on an array of orbits at different oribital radii we could potentially expand the VLBA from a few thousand kilometers to millions of kilometers.

    LC

  10. Carl Bramhall says

    I agree with the article. Steve clearly says that the Spektr will deliver fantastic science and the acheivment of getting the thing into space is amazing. But, ground based radio and optical telescopes are not compared with each other, so why should Spektr and Hubble. Even the James Webb Telescope (if it ever gets off the ground) is not really a successor to Hubble. It will be a sad day when Hubble can no longer operate.

  11. squidgeny says

    I think the article’s overall point is sound, but yes, it’s pretty damn unprofessional.

    It would have been perfectly fine if Steve had left out two bits – one trivialising the name of the telescope by comparing it to that of an anime character (actually, Spektr is Russian for Spectrum. I’m sure “Hubble” sounds silly to Russians too), and another bit that reads “(stifles laughter)”

  12. Justin Hartberger says

    Actually, I’d say it’s more of a ‘setting the facts straight’ display. He isn’t speaking badly about the telescope, but is criticizing the way the media is portraying it. In fact it has a lot of good info on the new telescope and how it will be used.

    Also, why would an Australian be jealous of a Russian telescope when compared to an American telescope? Oh wait…what country launched them or developed them doesn’t really matter anyway as they are used to benefit everyone with their data regardless.

    Really why would any scientifically-minded person get jealous over shiny new hardware to peek into the universe?

    American components, Russian components…ALL MADE IN TAIWAN! (sorry, couldn’t resist)

  13. “…it is just radio light conveyed information – which just can’t deliver the level of detail that nanometre wavelength visible light can carry.

    That’s why you can usefully create radio telescope arrays, but you can’t gain much value from arraying visible light telescopes…”

    You just made radio astronomers and visible light interferometer enhusiasts angry with the same article… 😉

    Sure, it’s not a “Russian Hubble”, but on the other hand, if the infrared James Webb space telescope ever launches, it’s not going to be a second generation visible light US Hubble either, although it is sold as such.

  14. Tia Boo says

    Unprofessionally written, and even if he didn’t mean it, it was demeaning.

  15. Member
    Steve_Nerlich says

    Note to self: Repeated use of the phrase ‘don’t get me wrong’ will do nothing to prevent people from getting you wrong.

  16. Member
    IVAN3MAN_AT_LARGE says

    It appears that only the British and Australians understand each other!

  17. Would a 1.7m UV telescope suffice then? (Yeah, its not visible light – neither will be the JWST.)

    http://wso.inasan.ru/

  18. Jasem Mutlaq says

    This is probably the worst article I read on universetoday! It reeks of bias and condescending tones.

  19. Anonymous says

    That was the most unashamedly biased article I’ve read here to date! Let’s hope it’s the last… There’s a world of excellent scientific research beyond the U.S. Report it fairly or not at all!

  20. Anonymous says

    That was the most unashamedly biased article I’ve read here to date! Let’s hope it’s the last… There’s a world of excellent scientific research beyond the U.S. Report it fairly or not at all!

  21. Anonymous says

    That was the most unashamedly biased article I’ve read here to date! Let’s hope it’s the last… There’s a world of excellent scientific research beyond the U.S. Report it fairly or not at all!

  22. Anonymous says

    True! And given the number of people who “got you wrong,” perhaps a deeper reassessment is in order.

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