> Finding anything at all that addresses your question about > limitations on what a telescope can see (resolve) turned out > to be harder than I expected.
Yes, thanks for you help Enrico. I am not surprized at all that astronomers never realized that the telescope and all the Physics laws on Optics were never seen as their best and finest measure of distance in the Cosmos.
I am guessing, roughly, that no telescope on Earth is able to see a galaxy beyond 200 million light years away. And that the furthest possible sighting of a supernova from Earth with our finest telescope is 400 million light years away.
So my guess is that 400 million light years is the furthest distance in astronomy that we can "know about."
This would mean that the surveys by Jarrett and Juric et al, are mappings that are all confined to 400 million light years. And not our current silly idea that our telescopes are peering back to 13 billion light years.
So all the surveys and mappings of the Cosmos have to take place within 400 million light years distance because our telescopes can see these objects and if we can see them in the telescope, means they are no further than 400 million light years.
> "Angular resolution > Ignoring blurring of the image by turbulence in the atmosphere > (atmospheric seeing) and optical imperfections of the telescope, the > angular resolution of an optical telescope is determined by the > diameter of the objective, termed its "aperture" (the primary mirror, > or lens.) The Rayleigh criterion for the resolution limit áR (in > radians) is given by"
> <Snipped math - not sure if it would display here>
> "Essentially; the larger the aperture, the better the angular > resolution"
> "It should be noted that the resolution is NOT given by the maximum > magnification (or "power") of a telescope. Telescopes marketed by > giving high values of the maximum power often deliver poor images."
Yes, resolution comes back to memory. There is another idea or concept in Physics when I took Optics in school. I sort of forgotten the concept or it is vague to me now. It went along the lines of something called "coherence of light". Meaning that the flashlight on Pluto directed to the Hubble Space Telescope may not be resolved by the telescope, but if I had a laser light flashlight, that Hubble telescope would then be able to resolve my flashlight on Pluto.
Of course the stars, galaxies and Supernova are not laser lights. And this concept of "coherence" is important in the distance that a telescope can resolve a shining light.
So, Enrico, I am not surprized at all, that the Physics community in conjunction with the Astronomy community never sat down and worked out, first, what the limit of their best telescopes are. Whether any of them can see beyond 200 million light years of a star or galaxy, or 400 million light years of a Supernova. For there is a definite upper limit of distance.
It does not surprize me that the Physics and Astronomy community have assumed their telescopes can see and peer to a infinite distance in Space. And the Big Bang theory accepts such a ridiculous assumption.
Now it maybe that radio telescopes can see further, but here again, there is an upper limit. And I am guessing that it is the RING seen in Jarrett's mapping that tells me this ring is the "edge of the observable horizon of the Cosmos". And that RING is about 400 million light years away. And thus, everything beyond that RING, is actually inside the ring or closer to earth.
Archimedes Plutonium wrote:
> Yes, resolution comes back to memory. There is another idea or concept > in Physics when I took Optics in school. I sort of forgotten the > concept > or it is vague to me now. It went along the lines of something called > "coherence of light". Meaning that the flashlight on Pluto directed to > the > Hubble Space Telescope may not be resolved by the telescope, but if I > had > a laser light flashlight, that Hubble telescope would then be able to > resolve > my flashlight on Pluto.
> Of course the stars, galaxies and Supernova are not laser lights. And > this > concept of "coherence" is important in the distance that a telescope > can > resolve a shining light.
It has been a very long time since I sat in a UC Optics classroom in 1970. And never knowing that such an experience was going to come out so fruitfull eventually.
So the question I raise is what is the maximum distance that the Hubble Space Telescope can see a ordinary galaxy. Maximum distance given the physics of how light travels and optics of the telescope. And it is a darn shame that noone in the astronomy community ever thought to ask such a question. The biologists certainly asked the questions a long time ago about the smallest length their light-microscopes could attain. And that if a biologist proclaimed to see a virus in a light-microscope would have been laughed out of his profession.
But nowadays, it is commonplace for astronomers and physicists to claim that quasars and the Sloan Great Wall are far beyond 400 million light years, yet the Hubble Space Telescope sees them as red spots, yet none of these scientists ever worked out whether Hubble Space Telescope can see a quasar or Great Wall in the billions of light years.
The limit of a light microscope is that of bacteria, so where is the limit of the Hubble Space Telescope. Most astronomers probably have the notion that telescopes have no limit to observing distances. That they think the Hubble can see and peer into infinity distance.
To me, such notions and assumptions are repulsive.
So now, how to find out the limit of distance of the Hubble Space Telescope? How do we find out its limit?
Well a good way is to ask a question such as whether a flashlight placed on Pluto or Mars or Moon can be seen by the Hubble Space Telescope? Have a gradation of flashlights on the Moon and see where the Hubble ceases to "see" the flashlight. Then we can extrapolate that luminosity of the flashlight and Moon distance to that of Supernova or regular galaxies as to what the Hubble Telescope upper limit of distance is.
Now I believe the prime reason there is a upper limit is the behaviour of light itself, in that it has a luminosity governed by inverse square of distance. If my memory serves me from 40 years ago in school studying Optics, this is called candela.
And the reason that laser light can be seen so much further of a distance is because of the "coherent beam" that does not fall off at inverse square of distance.
No galaxy , nor any supernova nor the quasars are laser lights, and so they fall off in luminosity by inverse square of distance.
So the question of using a telescope to tell us of the distance to a galaxy or a star or a quasar or a Sloan Great Wall, is that we can use standard Physics ideas, laws and principles of Optics to tell us how far a telescope can resolve a regular normal astro body. My guess is that the Hubble Space Telescope has a maximum distance range of 200 million light years for a normal regular single galaxy and any such galaxies beyond 200 million light years is not detectable by Hubble. For a Supernova, I am guessing 400 million light years distance the Hubble can still faintly see the Supernova, but beyond that distance is undetected.
Now why is this so very important? Well, obviously, since the quasars and Great Walls are alleged to be 13 billion and 4 billion light years away, yet easily seen in the Hubble Space Telescope as red spots, signifies that the redshift is all in error. If Hubble Telescope distance is only good to 200 to 400 million light years, then the quasars and Great Walls must be a smaller distance than 200 to 400 million light years.
Funny, how it seems that a logical thinker in astronomer is as rare to find as a Supernova explosion is rare to find. Because, it really does not need a rocketscientist to figure out that the telescope itself is a distance measuring tool and the most accurate measuring tool of distance in all of astronomy. So shame on the astronomy community for never realizing this valuable tool. Part of the problem is that so many scientists spend most of their time on thinking about equations of math and physics, and little time on clear logic. And so you have a 100 years of time wasted on Doppler redshift and no time spent on the telescope itself as a distance tool.
-- Approximately 90 percent of AP's posts are missing in the Google newsgroups author search starting May 2012. They call it indexing; I call it censor discrimination. Whatever the case, what is needed now is for science newsgroups like sci.physics, sci.chem, sci.bio, sci.geo.geology, sci.med, sci.paleontology, sci.astro, sci.physics.electromag to?be hosted by a University the same as what Drexel?University hosts sci.math as the Math Forum. Science needs to be in education?not in the hands of corporations chasing after the next dollar bill.?Besides, Drexel's Math Forum can demand no fake names, and only 5 posts per day of all posters which reduces or eliminates most spam and hate-spew, search-engine-bombing, and front- page-hogging. Drexel has?done a excellent, simple and fair author- archiving of AP sci.math posts since May 2012?as seen?here: