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Space Science

Largest Hubble Mosaics Ever Assembled 40

Posted by michael from the eye-candy dept.
bobtheowl2 writes "The Hubble Heritage team of astronomers, who assemble many of the NASA Hubble Space Telescope's most stunning pictures, is celebrating its five-year anniversary with the release of the picturesque Sombrero galaxy. One of the largest Hubble mosaics ever assembled, this magnificent galaxy is nearly one-fifth the diameter of the full moon. The team used Hubble's Advanced Camera for Surveys to take six pictures of the galaxy and then stitched them together to create the final composite image. The photo reveals a swarm of stars in a pancake-shaped disk as well as a glowing central halo of stars."
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Largest Hubble Mosaics Ever Assembled More

Largest Hubble Mosaics Ever Assembled

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  • Brave, brave people. (Score:3, Informative)

    by daeley ( 126313 ) * on Tuesday October 14, 2003 @12:25PM (#7210715) Homepage
    Very brave of them to make a 211 MB TIFF file available for download on this page [hubblesite.org]. ;)
    • At that size, makes you wonder if its to scale!
      • Ha Ha! You're silly. Of course it is to scale. I think what you mean is that you're wondering if it is to a 1-1 scale because as long as there is a correlation between the real world distances and the distances in the assembled work, there's a scale. So, no - it's not to a 1-1 scale. High resolution photographs, such as the ones that can be produced using Hubble, are pretty big - although, not that big. I bet there's a great compression scheme just waiting to happen on these photos though - lots and lots of
    • That image is well worth panning through: the sheer number of galaxies in the background is astonishing. I guess it's a big place, after all.

  • Aye, Cap'n! (Score:3, Informative)

    by rudy_wayne ( 414635 ) on Tuesday October 14, 2003 @12:28PM (#7210766)
    At Warp 9 we'll be there in 38,000 years!

  • 700km? (Score:2)

    by crow ( 16139 )
    this magnificent galaxy is nearly one-fifth the diameter of the full moon

    So the galaxy is less than 700km in diameter? Those must be the smallest stars ever discovered.

    (Yes, I know that they mean the mosaic covers a region of space that, as observed from earth, covers about one-fifth the diameter of the moon, but they could have worded it better.)

    • Re:700km? (Score:1)

      by PD ( 9577 ) *
      Their wording is actually a very common way for astronomers to describe how big something is. Usually people will say that something is N degrees in size, or X arc-seconds in size, but sometimes they will make reference to the diameter of the moon.

      It might not be the most precise and lawyerly language, but in the conventions of astronomical jargon it's unambiguous.
      • As I'm not an 'active' member any astronomers' circle, I'm still a bit confused as to what they're trying to say when they say that its 1/5 the diameter of the moon. Are they saying that the image produced by Hubble is 1/5 the size of the moon? But what magnification was Hubble operating under to produce that picture? It just seems like they're comparing apples and oranges since one body (the moon) is tangible, where as the other (the picture) is digital. Maybe you can help set me straight.
  • "this magnificent galaxy is nearly one-fifth the diameter of the full moon."

    The moon's diameter is 2140 miles. This equates to a galaxy less than 450 miles wide. How many stars can you fit into such a Minnesota-sized galaxy? How can you make it small enough to be accidentally swallowed by a small dog [demon.co.uk]?
  • There's also some nice video footage [hubblesite.org]
  • There's a number of stars in the foreground that are missing -- presumably, they prettied up the disk a bit to make it more photogenic. (Compare to this ESO shot [eso.org] and you'll see what I mean.) I'm always disappointed when NASA has to bend the truth -- even just a little bit.

    (I posted this on metafilter, but it bears a mention on slashdot.)

    • Okay, I compared them and they look the same to me. I don't see any large differences like missing stars. At least not obvious ones. You do realize that those two photos were taken with two different telescopes, right?
      • There are a number of missing stars -- look more carefully at the disk. There's a bright one on the left and a smattering on the right. And yes, I realize that ESO is not HST.
        • Okay, I looked again. I take it you mean the bright star on the left on the dust lane just a little past where the disk color turns from white to brown. Then two more to the left a little high and a little low. Well, they're there in the HST images, too.

          They're not there in the HST "screen" image, but the size is a lot smaller than the ESO image so that's expected.

          In the small HST "print" image, which is closer to the size of the ESO image, they are visible, but fainter.

          If you switch to the large H

    • Re:It's a photoshop job. (Score:4, Insightful)

      by LMCBoy ( 185365 ) on Tuesday October 14, 2003 @03:09PM (#7212723) Homepage Journal
      First of all, I don't see any stars in the ESO image that do not appear in the HST image, so what are you talking about?

      Maybe you mean that the stars in the ESO image look more prominent than they do in the HST image. That's because the VLT is on the ground, so the stars (which are very pointlike in the HST image) are slightly blurred.
      • With 6:00 as the point nearest us and 12:00 as the point diametrically opposed through the galactic nucleus--there's a bright one at 7:30, lower part of the dust disk. There's also a bunch on the top of the disk, between 2:00 and 5:00. (And they're all foreground stars, so they're not really associated with the disk).

        If you compare the other stars in the image, it's pretty clear that it's not a resolution artifact.

        • Peter,

          I am not usually this relentless, but as an employee at STScI, your accusation of fraud really annoys me.

          Anyway, I am prepared to prove you wrong. Please examine the animated GIF image I have placed at the following URL:
          http://www.stsci.edu/~jharris/sombrero.gif

          In the image, I have stacked the HST image and the VLT image on top of each other, and I am displaying each with the same scale and orientation. The first frame shows the HST image, the second frame shows the VLT image. You may need to
          • Your explanation makes sense; I couldn't see the alternate explanation for the selective dimming -- and now that there is one, I retract my accusation. (Moderators, please mod root post down.)
  • I'm wondering, what's the brown stuff? Is that gas? That's a whole lotta gas..
    • Dust. This galaxy is famous for having an obscuring ring of dust around it. It certainly adds to the photogenicity.

      • Indeed, it's dust. In order to get just a rough idea of how much dust that is, picture the following:

        The Messier 104 (Sombrero) galaxy contains anywhere between 210,000,000,000 [astrophoto.net] and 800,000,000,000 [hubblesite.org] stars (although the latter figure seems more likely to me, mostly because the estimate is newer). That is a whole lot of mass!

        Look at the image: given that the galaxy is about 50,000 lightyear across, the dust-band must be about 1,000 lightyears across. Just, for the sake of argument, assume that the dust is

        • When I was a grad student, I did numerical simulations of supernova remnant evolution. These blasts were simulated expanding into an interstellar region of H density 1 per cc. I imagine dust clouds would be anywhere between 100 to 1000 times more dense than the "normal interstellar medium".

          1 per cubic meter is FAR too low of an estimate (a million times less dense than I used, and my figure was based on published articles in The Astrophysical Journal), meaning there is probably a billion times more mass

          • I could have imagined that it would have been much more than 1 atom per cubic meter, since I thought that that would be the density of interstellar "vacuum", and the dust-clouds of course are much denser than that.

            Now, I'm a bit puzzled here: I always thought that there interstellar "vacuum" had about 5 atoms per cubic meter, while your figures would imply about 10e+6 per cubic meter. Where does the difference come from? It 5 atoms/m^3 the density in intergalactic space and 1e+6 atoms/m^3 that for interst

            • I don't remember the specifics, but an estimate of 5 H/cubic meter would seem to be appropriate for IGM density, as opposed to the 1 H/cc standard for ISM. The ISM figure is a total number density and is not based on visible luminosity calculations. Also, IIRC, the estimates are 8e+11 stars (800 hundred billion) in M104, not 8e+10. Finally, I don't think you remember your molecular cloud densities properly. Some of my collegues were simulating SNR shock waves impacting molecular clouds (to study the effi

  • Sadly, (Score:1)

    by pmz ( 462998 )

    the universe turns out to be in the form of a giant Goatse.cx ascii art picture. Astronomers everywhere are thrilled about their discovery but too embarrassed to publish it.

  • Does anyone else stare at this picture for >1 minute while readjusting their perspective?

    This would be an amazing picture even if it were only fictional artwork. The fact that it's real makes it all the more amazing...

    If you only glanced, then go back and pause for a moment. Make sure you view the 435kiB version [hubblesite.org] so you can see the details...
  • this magnificent galaxy is nearly one-fifth the diameter of the full moon

    This reminds me of an image I seen lately, here [noao.edu].

    It was really a suprise to learn just how big these objects are in the sky despite the unimaginable distance. That and just how dim they are! Even our own galaxy is a faint band of light despite us being right inside it. It's a shame really, imagine seeing the Andromeda galaxy like in that picture high in the sky!
    • Yes thats an impressive picture that make a good point. It shows that one of the best ways to see the night sky is with a pair of fairly low mag binoculars with big lenses to concentrate the light.

      Oh and you need dark skies too..
  • Can that Mission3-D's Photo3-D 303 kit handle this?

    Then slap it into Freelancer, and I'll fly around for a look. :)

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