Hallo Zusammen,
Da mich dieses Thema nicht mehr in Ruhe gelassen hat, habe ich dazu mal einen netten Prof vom LBT in Deutschland befragt, hier seine Antwort:
Vom Hubble-Teleskop wurde eine Ultra-Deepfield-Aufnahme mit einer
> Entfernung von ca. 13,4 Mrd. Lichjahren angefertigt, die
> Belichtungszeit betrug 11,3 Tage. Hier nun meine Fragen:
>
> - ist Hubble damit an seiner Leistungsgrenze angelangt, oder wären
> noch größere Entfernungen möglich - vorausgesetzt das Teleskop würde
> dazu noch länger zur Verfügung stehen?
This is indeed close the limit of what the telescope practically can do. If you increase the exposure time to f.ex. 100days the gain will not be very big. You can decrease the so called random errors and noise sources but the systematic errors which normally are at a very low level start to become the dominating source of noise and systematic errors do not go away even if you observe for ten times as long time.
>
> - Ich gehe mal davon aus, dass das LBT aufgund seiner Adaptiven Optik
> eine noch höhere Auflösung als Hubble hat und dadurch noch weitere
> Aufnahmen anfertigen könnte.
Yes, in the near IR (K-band) the LBT will indeed have a resolution which is almost 10 times higher than that of the Hubble Space Telescope.
>
> - falls dies technisch möglich ist, würde sich der Zeitaufwand nicht
> lohnen um Fragen zur Entstehung unseres Universums und vor allem zum
> Urknall zu klären, da dies doch die primäre Aufgabe von Teleskopen ist?
The LBT will of course also be used to look at some of the most distance objects in the Universe, but don't forget that it is not possible to look all the way back to the big bang as there were no objects at that time, at least not objects as we know them. Galaxies only formed much later, we still do not know exactly when, and stars at such distances would most likely be too faint to be detected. Actually the telescope that has looked furthest back is the satellite WMAP which studied the microwave background. This is probably the earliest available photons for observations today and they were observed with a 1m antenna. Actually the microwave radiation was detected already in the 1960's on earth with a small microwave antenna by accidence, so it is not only the size of a telescope but also the wavelength that makes the difference for how 'old' photons it will be able to observe. And even these photons were emitted several 100.000 years after the big bang itself, before that the gas was so hot that photons would get destroyed all the time by collisions and interactions with other particles, so none of these photons could have survived to reach us.
MfG,
-- Jesper Storm