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#11
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Sharper than Hubble: Large Binocular Telescope achieves majorbreakthrough
On 12/20/11 12:56 PM, Sam Wormley wrote:
On 12/19/11 3:37 PM, Brad Guth wrote: Obviously you and others of your FUD-master kind can't think of one darn thing that our Earth-moon L1 is good for. Lagrange Points http://scienceworld.wolfram.com/phys...ngePoints.html Better http://en.wikipedia.org/wiki/Lagrangian_point |
#12
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Sharper than Hubble: Large Binocular Telescope achieves majorbreakthrough
On 12/19/11 3:37 PM, Brad Guth wrote:
Obviously you and others of your FUD-master kind can't think of one darn thing that our Earth-moon L1 is good for. Lagrange Points http://www.wolframalpha.com/input/?i=Lagrange+Points+ |
#13
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
On Dec 20, 11:04*am, Sam Wormley wrote:
On 12/19/11 3:37 PM, Brad Guth wrote: Obviously you and others of your FUD-master kind can't think of one darn thing that our Earth-moon L1 is good for. * *Lagrange Points * * *http://www.wolframalpha.com/input/?i=Lagrange+Points+ ? |
#14
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
On Dec 20, 11:01*am, Sam Wormley wrote:
On 12/20/11 12:56 PM, Sam Wormley wrote: On 12/19/11 3:37 PM, Brad Guth wrote: Obviously you and others of your FUD-master kind can't think of one darn thing that our Earth-moon L1 is good for. Lagrange Points http://scienceworld.wolfram.com/phys...ngePoints.html * *Better * * *http://en.wikipedia.org/wiki/Lagrangian_point ? |
#15
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
On Dec 20, 10:56*am, Sam Wormley wrote:
On 12/19/11 3:37 PM, Brad Guth wrote: Obviously you and others of your FUD-master kind can't think of one darn thing that our Earth-moon L1 is good for. * *Lagrange Points * * *http://scienceworld.wolfram.com/phys...ngePoints.html ? |
#16
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
In article ,
"Mike Dworetsky" writes: The new best place for observing is at the Earth-Sun Lagrangian point L2, especially for Infrared observatories. This is really a minor quibble, but is it clear that L2 is better than solar orbit (used for Spitzer and Kepler)? I haven't seen the orbit tradeoff study for JWST (which is going to L2). My main worry is that L2 requires use of hydrazine for station keeping, and that can contaminate optical surfaces. L2 has a communication advantage, but using a big high-gain antenna and/or more powerful transmitter should give adequate data rate from solar orbit. As for Earth-Moon L1, see my .sig. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
#17
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Sharper than Hubble: Large Binocular Telescope achieves majorbreakthrough
This is really a minor quibble, but is it clear that L2 is better
than solar orbit (used for Spitzer and Kepler)? I haven't seen the orbit tradeoff study for JWST (which is going to L2). An observatory at L2 will have a relatively constant distance for its lifetime, while an observatory in a trailing solar orbit will have its distance gradually increasing, meaning a loss of bandwidth in later years. |
#18
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
Steve Willner wrote:
In article , "Mike Dworetsky" writes: The new best place for observing is at the Earth-Sun Lagrangian point L2, especially for Infrared observatories. This is really a minor quibble, but is it clear that L2 is better than solar orbit (used for Spitzer and Kepler)? I haven't seen the orbit tradeoff study for JWST (which is going to L2). My main worry is that L2 requires use of hydrazine for station keeping, and that can contaminate optical surfaces. L2 has a communication advantage, but using a big high-gain antenna and/or more powerful transmitter should give adequate data rate from solar orbit. Yes, but it reduces the amount of mass budget available for telescope and detector equipment if the antenna has to be larger. Also, you can save a small amount of delta-V by not having to go into orbit around the sun. I wonder if there is a technical spec somewhere that explains why L2 vs solar orbit. As for Earth-Moon L1, see my .sig. -- Mike Dworetsky (Remove pants sp*mbl*ck to reply) |
#19
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
Steve Willner wrote:
In article , "Mike Dworetsky" writes: The new best place for observing is at the Earth-Sun Lagrangian point L2, especially for Infrared observatories. This is really a minor quibble, but is it clear that L2 is better than solar orbit (used for Spitzer and Kepler)? I haven't seen the orbit tradeoff study for JWST (which is going to L2). My main worry is that L2 requires use of hydrazine for station keeping, and that can contaminate optical surfaces. L2 has a communication advantage, but using a big high-gain antenna and/or more powerful transmitter should give adequate data rate from solar orbit. Ah. Got it. The real-time control exchange of signals at L2 from ground to spacecraft would be about 7-8 sec rather than a few minutes. My guess is that this is the reason L2 is preferred. As for Earth-Moon L1, see my .sig. -- Mike Dworetsky (Remove pants sp*mbl*ck to reply) |
#20
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Sharper than Hubble: Large Binocular Telescope achieves major breakthrough
On Dec 21, 12:23*pm, (Steve Willner) wrote:
In article , *"Mike Dworetsky" writes: The new best place for observing is at the Earth-Sun Lagrangian point L2, especially for Infrared observatories. This is really a minor quibble, but is it clear that L2 is better than solar orbit (used for Spitzer and Kepler)? *I haven't seen the orbit tradeoff study for JWST (which is going to L2). *My main worry is that L2 requires use of hydrazine for station keeping, and that can contaminate optical surfaces. *L2 has a communication advantage, but using a big high-gain antenna and/or more powerful transmitter should give adequate data rate from solar orbit. As for Earth-Moon L1, see my .sig. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner * * * * * *Phone 617-495-7123 * * Cambridge, MA 02138 USA Right, a 256 thousand tonne do-everything science platform and lunar space elevator at the Earth-moon L1 is entirely worthless. http://translate.google.com/# Brad Guth, Brad_Guth, Brad.Guth, BradGuth, BG / “Guth Usenet” |
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