That’s WMAP, Seen from Earth

Article written: 9 May , 2008
Updated: 24 Dec , 2015
by



Okay, now astronomers are just showing off. See the three little multicolored dots in the upper right of this image? That’s NASA’s WMAP satellite, seen from a distance of 1.5 million km. The photograph was taken from the 2.2 meter telescope at the European Southern Observatory at La Silla, Chile. Apart from demonstrating some impressive imagine power and technique, the astronomers are testing out new tracking techniques for ESA’s upcoming Gaia space observatory.

The technique for finding your place in the Universe is called astrometry. Star Trek’s Enterprise would rely on this kind of information to navigate from star to star. In reality, though, astronomers compile this information to understand the Solar System’s position in relation to the rest of the Milky Way.

The last mission focused on this process was ESA’s Hipparcos mission, which wrapped up in the year 1993. Hipparcos measured the distance to 120,000 stars with great accuracy, as well as another 400,000 stars with less accuracy.

ESA’s new mission, due for launch in 2011, is called Gaia, and will travel to the Sun-Earth L2 Lagrangian point. From this vantage point, it’ll create a precise three-dimensional map of stars throughout the Milky Way galaxy, and beyond. All in all, it will eventually create a catalogue of 1 billion stars.

When Gaia finally launches, knowing its position accurately in the Solar System is everything. And so, astronomers on Earth will need to be able to track its position in the sky, and relay this data back to the spacecraft, so it can make its calculations.

By demonstrating that they can already track the WMAP spacecraft, currently at the L2 Lagrangian point, the astronomers have proven that they should be able to watch Gaia as well. In fact, Gaia should be brighter than WMAP.

You might be wondering why the WMAP image shows three different colours. The astronomers photographed the region three times in black and white, and then artificially coloured them red, blue and green. Since the stars don’t move, the three colours add up to make them appear white. The moving WMAP is clearly different from the background.

Original Source: ESA Image of the Week


7 Responses

  1. Nasikabatrachus says

    What’s the point of photographing it three times in black and white and then coloring it artificially?

  2. DavidRavenMoon says

    Q: “What’s the point of photographing it three times in black and white and then coloring it artificially?”

    A: “Since the stars don’t move, the three colours add up to make them appear white. The moving WMAP is clearly different from the background.”

    The only thing in color is the thing that’s moving from one photo to another.

    Now the real question is why fudge the color of photos from Mars to make it look redder? 😉

  3. Astrofiend says

    “# Nasikabatrachus Says:
    May 9th, 2008 at 2:10 pm

    What’s the point of photographing it three times in black and white and then coloring it artificially?”

    A: The photos aren’t actually all just black and white – i.e. they don’t just end up with three black & white photos and then arbitrarily assign red green and blur colours to them.

    What they actually do is take a monochrome (greyscale) image through three different colour filters – one red, one blue and one green. So in effect, you have a red image, a blue image and a green image once the monochrome images are assigned their ‘filter colours’ by a computer. These are then combined to produce a full colour image.

    Why do they do it this way and not just take a colour image in the first place? The answer is because they can’t – a CCD detector (which is what they use to take the pictures) only records images in greyscale. Even so-called colour CCD chips, like in cameras, are nothing more than normal CCD chips with millions of tiny little RGB filters covering the pixels. So to have a colour image of an object, you have to combine the RGB filtered images. It’s the same principle as a CRT TV image – individual red, green and blue pixels are combined to yield a full colour picture.

    Now, why did they bother doing that with this image? the answer is – stars look white in full colour and so do most satellites. So they could either take three black and white images and search for the ‘star that moves’ between frames (which looks easy in small cropped pictures above, but may be time consuming in a large full-CCD picture) or they can combine the RGB images and simply look for the three coloured points characteristic of a moving object.

  4. pradipta says

    Telescope enlarges view not closes near view. Following may clear the concept.
    “A visitor of a desert often find mirage. If he moves, mirage also moves. He can never reach near the mirage. If he tries he can see enlarge view of mirage as smoky atmosphere through a telescopic instrument”.
    Giant telescope like Hubble and others may be the milestone of our technology but it can not help the real space research because we are capable to see the original objects of solar system within the radius of 150 million kilometer only. Ahead of it everything is mere image into space mirror.
    Visit http://www.spacemirrormystery.com to know the original truth.

  5. Astrofiend (Syd, Aust) says

    pradipta Says:
    May 11th, 2008 at 12:04 pm

    “Giant telescope like Hubble and others may be the milestone of our technology but it can not help the real space research because we are capable to see the original objects of solar system within the radius of 150 million kilometer only. Ahead of it everything is mere image into space mirror.”

    Pradipta, if we can only see objects within a radius of 150 million kilometres, then why can we communicate via electromagnetic radiation with spacecraft far beyond that distance, or watch as comets sail through from much closer to us than that right out, through that distance to much farther away? There are literally billions of astronomical observations that are completely at odds with your principle assertion, which seems to be that there is some sort of mysterious mirror or lensing effect that creates the perfect illusion of the existence of everything beyond a tiny little bubble in our Solar System.

    Sorry, but your theory is rubbish. So is your website, by the way.

  6. pradipta says

    As light the power of remote reflect in mirror.

    Suppose you are watching a space film on a Television set and such film’s image also appearing to you in a mirror fixed by near wall. Now you are bored and liked to change another channel through the remote control of the television. You can do such work either by directing directly on real television or by directing on image.

    Through remote world space research organizations send man less space vehicle to different space objects. Guess Astrofiend (Syd, Aust) about genuineness of your last comment.

  7. alphonso richardson says

    Ooh, pretty…………………….

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