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Thread: Aurora Australis Courtesy Of ISS Expedition 23

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    Default Aurora Australis Courtesy Of ISS Expedition 23


    NASA Human Space Flight (HSF) gallery
    :
    International Space Station (ISS), Expedition XXIII.


    Photo ID No. ISS023-E-058455

    Captured with Nikon D3 @ ISO 6400



    Photo ID No. ISS023-E-057948

    Travelling at an average speed of 27,743.8 km/h, photography opportunities for sunset and sunrise only last a couple of seconds or so

    Last edited by 9V-Orion Images; 23rd June 2010 at 02:54 AM.
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Wonder why the Aurora Australis is green in color? Does it have anything to do with why Australia National Sport color being also green? Interestingly the shot was taken at 1/6" and the ISS is flying at WHAT?, an average speed of 27,743.8 km/h?
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by DrSpock View Post
    Wonder why the Aurora Australis is green in color? Does it have anything to do with why Australia National Sport color being also green? Interestingly the shot was taken at 1/6" and the ISS is flying at WHAT?, an average speed of 27,743.8 km/h?
    The green glow is a result of photon emission from electronically excited oxygen atoms decaying to a less energetic state.

    Hopefully the ISS crew member did not receive too much of an ionizing radiation dosage as auroras are often preceded by a Coronal Mass Ejection (CME) or geomagnetic sudden impulse from the sun that occurred days beforehand.

    Last edited by 9V-Orion Images; 23rd June 2010 at 09:22 PM.
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by 9V-Orion Images View Post
    The green glow is a result of photon emission from electronically excited oxygen atoms decaying to a less energetic state.

    Hopefully the ISS crew member did not receive too much of an ionizing radiation dosage as auroras are often preceded by a Coronal Mass Ejection (CME) or geomagnetic sudden impulse from the sun that occurred days beforehand.
    Wow, thanks 9V-Orion Images for the indepth answer. I thought they may be Gamma rays that supposely give HULK his powers

    When you say oxygen atoms is it from the ozone layer or O2 in the atmosphere?

    BTW, are you some kind of Professor in Quantum Physics or just for hobby?
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by DrSpock View Post
    Wonder why the Aurora Australis is green in color? Does it have anything to do with why Australia National Sport color being also green? Interestingly the shot was taken at 1/6" and the ISS is flying at WHAT?, an average speed of 27,743.8 km/h?
    It's the orbital speed to keep the ISS in the desired orbit.

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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by DrSpock View Post
    When you say oxygen atoms is it from the ozone layer or O2 in the atmosphere?
    I am referring to atomic and molecular oxygen within the ionosphere.
    Quote Originally Posted by DrSpock View Post
    BTW, are you some kind of Professor in Quantum Physics or just for hobby?
    I am just an aerospace engineer by training though I often read up on my subjects of interest.
    Last edited by 9V-Orion Images; 24th June 2010 at 11:26 PM.
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by lsisaxon View Post
    It's the orbital speed to keep the ISS in the desired orbit.
    Yes, I understand that part about orbit but what I meant was at that speed should'nt the photo be a blur instead of so sharp? It must be the Theory of Relativity and they use D3

    Quote Originally Posted by 9V-Orion Images View Post
    I am referring to atomic and molecular oxygen within the ionosphere.

    I am just an aerospace engineer by training though I often read up on my subjects of interest.
    OIC, I'm also an Engineer but only specialise in drains & roads lah I used to read up on astronomy and ever dreamt of being an astronaut but I guess no chance in the world now unless I pay $20m
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by lsisaxon View Post
    It's the orbital speed to keep the ISS in the desired orbit.
    I think it's where the earth rotating speed is plus the altitude distance to the ISS. The further the ISS is away from our planet, the more circumference distance it will orbit.

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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by Spectrum View Post
    I think it's where the earth rotating speed is plus the altitude distance to the ISS. The further the ISS is away from our planet, the more circumference distance it will orbit.
    It's something to do with the centrifugal forces vs the gravity of the earth so for different orbit the slower/faster the speed or something like that. Maybe 9V Orion can explain better
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    Default Re: Aurora Australis Courtesy Of ISS Expedition 23

    Quote Originally Posted by DrSpock View Post
    Yes, I understand that part about orbit but what I meant was at that speed should'nt the photo be a blur instead of so sharp? It must be the Theory of Relativity and they use D3.
    The Earth is significantly large as a terrestrial planet and it still requires the ISS approximately 91 minutes to circle the globe at an orbital inclination of 51.64 degrees and as such the high orbital velocity of 27,743.8 km/h might not be entirely noticeable from the visual perspective of the astronauts on board the ISS in Low Earth Orbit (LEO). If the lens used for the shot was wide enough, motion blurring of the image from a shutter speed of 1/6 second could be insignificant though the image at high resolution does not seems to be entirely sharp to me either.

    Here are some of the latest still satellite imagery of the Republic of Singapore taken by ISS crew members of the same expedition (Expedition XXIII), all images are shot hand-held with either a Nikon D3 or D3X FX DSLR at a focal length of 800mm.


    Photo ID No. ISS023-E-31951
    High resolution copy with intact EXIF data is available via FTP as provided in the link above


    Photo ID No. ISS023-E-31950
    High resolution copy with intact EXIF data is available via FTP as provided in the link above


    Photo ID No. ISS023-E-31948
    High resolution copy with intact EXIF data is available via FTP as provided in the link above


    Photo ID No. ISS023-E-31947
    High resolution copy with intact EXIF data is available via FTP as provided in the link above


    Photo ID No. ISS023-E-31946
    High resolution copy with intact EXIF data is available via FTP as provided in the link above

    Quote Originally Posted by DrSpock View Post
    It's something to do with the centrifugal forces vs the gravity of the earth so for different orbit the slower/faster the speed or something like that. Maybe 9V Orion can explain better.
    Hmm..., not too sure if I have your inquiry right but if I am not mistaken a lower velocity is required to maintain orbit with an ever increasing altitude away from the Earth's surface though a significantly larger delta-v budget requirement is needed to reach a Medium Earth Orbit (MEO) or GeoStationary Earth Orbit (GEO) as compared to a Low Earth Orbit (LEO). :)
    Last edited by 9V-Orion Images; 25th June 2010 at 10:00 PM.
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