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Post by turbonium on Aug 5, 2005 22:05:04 GMT -4
So, we have the ability to see the landing sites, after all. They stated in the article that it wuld be pushing the limits of a single scope to see anything, nd they'd hve to have all four online to really see. As far as I know they haven't got all of them online yet. No, they have had all four in operation for some time. In fact, they have added two of four planned auxilliary telescopes to the system to provide more configurations and flexibility for multiple tasks. From this link www.eso.org/outreach/press-rel/pr-2004/pr-01-04.htmlThe VLT Interferometer
The VLTI incorporates the four gigantic 8.2-m telescopes that have already been installed at this remote mountain observatory and are operated every night in the year. Combining the light from the celestial objects, caught by pairs of these telescopes, at one focal point increases the resolving power of the instrument. So, they really can use the VLT to get close-up images of the landing sites, no question of that. Why they haven't, I don't know. I'll be emailing again in search of a reply. In the meantime, I thought I'd post a couple of amazing images taken by the VLT. Even though they may be color composites, they are really breathtaking!
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Post by sts60 on Aug 6, 2005 6:21:06 GMT -4
Reading that link shows that the big telescopes are working, but the interferometric functions that will "ultimately" (their word) allow the super-duper resolution isn't complete yet.
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Post by turbonium on Aug 7, 2005 0:04:52 GMT -4
Reading that link shows that the big telescopes are working, but the interferometric functions that will "ultimately" (their word) allow the super-duper resolution isn't complete yet. Dr. West, who I quoted in the first post of this thread, retired from ESO in March of this year , so I'm still trying to find more information on the project. But, according to Dr. David Darling, as I also quoted earlier, the VLT is capable of "giving a picture as sharp as if it had come from a single telescope 200 m across. If there were cars on the Moon, the Very Large Telescope would be able to read their number plates." Dr. Darlng, is a renowned astrophysicist with a PhD in Astronomy. I don't think he would make such comments off hand without knowing what the VLT is capable of doing. Nevertheless, I have also sent him an email in hopes that he has more information about the VLT imaging the landng sites.
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Post by sts60 on Aug 7, 2005 11:07:03 GMT -4
From the context, it seems clear he was describing the theoretical capability of the observatory once operational, not its current capability. But I'd like to hear what he has to say in his email.
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Post by JayUtah on Aug 8, 2005 10:09:38 GMT -4
Dr. Darlng, is a renowned astrophysicist with a PhD in Astronomy. I don't think he would make such comments off hand without knowing what the VLT is capable of doing.
But he may be speaking in hyberbole. When you make statements such as, "I don't think he would..." then you, not Dr. Darling become the authority for the claim.
Often scientists involved with extreme engineering problems do make statements like this in order to inspire awe and appreciation, and not with the intent that they be taken as literally true.
A 200 meter aperture at a wavelength of 500 nanometers gives an angular resolution of 0.00000000305 radian, or 0.000629 arcsecond. At lunar distance that's just under four feet. So no, it does not seem possible that the array can read license plates on the moon.
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Post by JayUtah on Aug 8, 2005 16:37:07 GMT -4
"The poor brightness sensitivity of interferometric observations mean that they could not be used for imaging objects with low surface brightness such as the moon. Only targets which are at temperatures of more than 1000 °C have a surface brightness high enough to be observed in the mid-infrared, and objects must be at several thousands of degrees for near-infrared observations using the VLTI. This sensitivity limit rules out interferometric observations of most solar-system objects apart from the Sun." en.wikipedia.org/wiki/Very_Large_Telescope
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Post by turbonium on Aug 8, 2005 22:14:44 GMT -4
But he may be speaking in hyberbole. When you make statements such as, "I don't think he would..." then you, not Dr. Darling become the authority for the claim.That would apply to yourself when you say "he may be speaking in hyperbole" We can only take his statements at face value, and any interpretations would simply be speculation. Often scientists involved with extreme engineering problems do make statements like this in order to inspire awe and appreciation, and not with the intent that they be taken as literally true.Again, you are further offering your personal interpretation of his statement without basis to do so. A 200 meter aperture at a wavelength of 500 nanometers gives an angular resolution of 0.00000000305 radian, or 0.000629 arcsecond. At lunar distance that's just under four feet. So no, it does not seem possible that the array can read license plates on the moon.www.airspacemag.com/ASM/Mag/Index/2000/JJ/lite.htmlAccording to the above link, "When this telescope is complete, it will have the angular resolution equivalent to that of a telescope with a mirror 132 meters [433 feet] in diameter," Gilmozzi begins. "That means that we will, if we wanted to, be able to resolve and photograph Apollo debris left on the moon.""The poor brightness sensitivity of interferometric observations mean that they could not be used for imaging objects with low surface brightness such as the moon. Only targets which are at temperatures of more than 1000 °C have a surface brightness high enough to be observed in the mid-infrared, and objects must be at several thousands of degrees for near-infrared observations using the VLTI. This sensitivity limit rules out interferometric observations of most solar-system objects apart from the Sun."I consider the director of the VLT, whom I quoted above, as well as the quotes from Dr. West and Dr. Darling, far more credible than Wikipedia, an "encyclopedia" of dubious reliabilty where information can be edited by anybody on the internet.
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Bob B.
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Post by Bob B. on Aug 8, 2005 23:15:47 GMT -4
But he may be speaking in hyberbole. When you make statements such as, "I don't think he would..." then you, not Dr. Darling become the authority for the claim.That would apply to yourself when you say "he may be speaking in hyperbole" We can only take his statements at face value, and any interpretations would simply be speculation. But since his statement is clearly contradictory, i.e. a 200 m telescope cannot see license plates at the Earth-Moon distance, it would be foolish to take his statement at face value.
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Post by papageno on Aug 9, 2005 6:32:47 GMT -4
I consider the director of the VLT, whom I quoted above, as well as the quotes from Dr. West and Dr. Darling, far more credible than Wikipedia, an "encyclopedia" of dubious reliabilty where information can be edited by anybody on the internet. This is ironic from somebody who uses CT sites as sources and provides quotes taken out of context. And JayUtah explained why he considers that quote as a hyperbole: Do you have something more substantial than " I take the out-of-context quotes I provide at face value"? EDIT to fix spelling.
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Post by gwiz on Aug 9, 2005 8:40:44 GMT -4
Dr. Darlng, is a renowned astrophysicist with a PhD in Astronomy. I don't think he would make such comments off hand without knowing what the VLT is capable of doing. David Darling's website appears to be a one-man encyclopaedia of astronomy and spaceflight. I don't think anyone has the expertise to compile all that information without a few mistakes creeping in. Apart from getting the basic VLT interferometer setup working, there is also the problem of countering the distortion of the atmosphere with the adaptive optics. I would imagine that this would be more of a problem for the interferometer than for an individual telescope, so it could take some time for the system to be developed to reach its ultimate theoretical performance.
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Post by gwiz on Aug 9, 2005 8:54:43 GMT -4
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Post by JayUtah on Aug 9, 2005 10:01:58 GMT -4
We can only take his statements at face value, and any interpretations would simply be speculation.Including yours. It is just as inappropriate to infer that his statement was intended literally as it is to infer that he intends to exaggerate. That is why I provided two additional data points in favor of my interpretation: the notion that even technical people involved with superlative engineering sometimes exaggerate for effect, and the diffraction limit calculation that shows he cannot be literally correct. While my statement is indeed interpretation, it is interpretation backed up by supporting fact. Your statement is also interpretation, but you have no defense for it other than that you wish it to be true. Again, you are further offering your personal interpretation of his statement without basis to do so.Hogwash. For many years I have been an engineer and a scientist engaged in producing superlative technology. For example, a few years ago my company built the third most powerful computer on the planet. My basis is years of firsthand experience and observation. That qualifies my opinion as evidence, not of his specific intent but certainly of the propensity. "Reading license plates" on the moon smacks of braggadocio, to which even scientists are not fully immune. www.airspacemag.com/ASM/Mag/Index/2000/JJ/lite.htmlAccording to the above link, "When this telescope is complete, it will have the angular resolution equivalent to that of a telescope with a mirror 132 meters [433 feet] in diameter," Gilmozzi begins. "That means that we will, if we wanted to, be able to resolve and photograph Apollo debris left on the moon."[/i] But that is not the same thing as reading license plates, which is the claim I tested. The estimate of 200 meters effective aperture was shown to have an effective resolution of just under four feet on the lunar surface. That would give it the resolution to render -- with extreme fuzziness -- some of the larger portions of Apollo remnants: the LRV and the LM descent stages, but not the flag or miscellaneous jetsam. I consider the director of the VLT, whom I quoted above, as well as the quotes from Dr. West and Dr. Darling, far more credible than Wikipedia, an "encyclopedia" of dubious reliabilty where information can be edited by anybody on the internet.The references to reading license plates have an exaggerational tone. Further, the claim was tested according to well-established scientific principles and found not to be literally possible. Contrary to your belief, the Wikipedia articles cannot be "edited by anybody on the internet." Scientific articles especially are carefully watched by the editorial committee and inappropriate changes are reverted. And again, I have seen this firsthand. Further, the Wikipedia article reproduces not just some specific point regarding the VLT, but a well-established principle of interferometry itself, to which the VLT is subject and which has already been discussed here (i.e., the effect of light-gathering power). Most importantly, because it is a group effort, Wikipedia is less prone to exaggeration, which is the key interpretational issue here. In another thread you warned me of the dangers of not thinking for myself and of accepting someone else's claims simply because they were offered. Here I have demonstrated that I am professionally competent to evaluate the claims being made and have given the reasons for disbelieving some aspects of it. You, on the other hand, have handily demonstrated that you are the one believing and disbelieving implicitly. I have offered two specific arguments in favor of my interpretation. One is from long experience. That is subjective and you may disagree. The other is a cold, hard scientific computation. It may be incorrect, in which case you are invited to locate the error. But if correct it may not be simply set aside as irrelevant or uncomfortable. It stands in direct contrast to the claims of reading license plates on the moon with an optical interferometer. On the other hand, the justification for your interpretation is based simply on your vague generality that statements should be taken at face value, and another equally vacuous assertion that some particular person is automatically more credible, therefore every specific claim of his must be true. In other words, you're just demanding that you're right. Not convincing.
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Post by turbonium on Aug 10, 2005 22:58:23 GMT -4
I have received a response from Henri Boffin from the ESO. I appreciate the time he kindly took to answer my questions very clearly and thoroughly. Below is his response in it's entirety..
Dr. West forwarded me your email.
It is correct that ESO's VLT is technically able to produce extremely sharp "images" by means of the interferometric technique when several telescopes are coupled together. It has in fact already produced a great number of outstanding results that you can see in some ESO Press Releases. Whether the resulting resolution (image sharpness) is sufficient to see "artificial" objects on the Moon remains still to be seen. I am afraid therefore that no "image" exist yet.
In fact, in its interferometric mode, the VLT has indeed a resolution equivalent to about 2m at the distance of the Moon. Thus it could barely distinguish the lunar modules - in principle. However, this cannot be achieved by just taking an image but requires a long and painstaking process where an "image" could be reconstructed.
Kind regards,
Henri Boffin, PhD ESO Public Affairs Dept.
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Post by ajv on Aug 10, 2005 23:12:10 GMT -4
I have received a response from Henri Boffin from the ESO. I appreciate the time he kindly took to answer my questions very clearly and thoroughly. Below is his response in it's entirety.. Thanks for doing that and reporting the result.
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Post by Mr Gorsky on Aug 11, 2005 10:31:51 GMT -4
Without wanting to cheapen the discussion unduly, you have to love a guy working in the scientific field with a name like Boffin, dont' you ...
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