211
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
F. Sánchez, The Rise of Astrophysics in Modern Spain, Astronomers’ Universe,
https://doi.org/10.1007/978-3-030-66426-8_21
21
The Biggest, Most Advanced Telescope
in the World (1989–Present)
To simplify matters greatly, we may consider a telescope to be a collector of
photons (a funnel that captures and concentrates the light of the stars). The
bigger the mouth of the funnel, the more photons it can gather and, therefore,
the greater its capacity for capturing light (electromagnetic waves to be exact)
from very weak or distant objects. But optics also tells us that the diameter of
the mirror determines the resolving power of the telescope. Resolving power
is the ability to separate two objects that apparently form a single object to the
naked eye. In other words, a bigger diameter enables the Universe to be
observed in greater depth and finer detail.
These properties explain the obsession of professional astronomers with
telescopes of greater diameter than provided by current technology and their
desire to locate them on sites with very special atmospheric conditions in
order to ensure the greatest number of nights of high astronomical quality. All
this has been explained in earlier chapters.
The atmosphere, always the astronomer’s greatest enemy, acts as a thick
perturbing medium nuzzled against the aperture of any terrestrial telescope.
Clouds prevent the stars from being seen at all, and, even in their absence,
atmospheric turbulence smears stellar images. This latter is not so obvious and
requires some sort of explanation, which I shall give in an elementary way. We
have all had the experience of seeing how objects a long way off on a heated
road shimmer, becoming distorted and blurred. The light from distant objects
must traverse seething bubbles of hot air, which alter the straight path that the
light would otherwise have taken, so that the image on our retina, or any
other optical detector, jitters and blurs. This is also the cause of the twinkling
of the stars.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
F. Sánchez, The Rise of Astrophysics in Modern Spain, Astronomers’ Universe,
https://doi.org/10.1007/978-3-030-66426-8_21
21
The Biggest, Most Advanced Telescope
in the World (1989–Present)
To simplify matters greatly, we may consider a telescope to be a collector of
photons (a funnel that captures and concentrates the light of the stars). The
bigger the mouth of the funnel, the more photons it can gather and, therefore,
the greater its capacity for capturing light (electromagnetic waves to be exact)
from very weak or distant objects. But optics also tells us that the diameter of
the mirror determines the resolving power of the telescope. Resolving power
is the ability to separate two objects that apparently form a single object to the
naked eye. In other words, a bigger diameter enables the Universe to be
observed in greater depth and finer detail.
These properties explain the obsession of professional astronomers with
telescopes of greater diameter than provided by current technology and their
desire to locate them on sites with very special atmospheric conditions in
order to ensure the greatest number of nights of high astronomical quality. All
this has been explained in earlier chapters.
The atmosphere, always the astronomer’s greatest enemy, acts as a thick
perturbing medium nuzzled against the aperture of any terrestrial telescope.
Clouds prevent the stars from being seen at all, and, even in their absence,
atmospheric turbulence smears stellar images. This latter is not so obvious and
requires some sort of explanation, which I shall give in an elementary way. We
have all had the experience of seeing how objects a long way off on a heated
road shimmer, becoming distorted and blurred. The light from distant objects
must traverse seething bubbles of hot air, which alter the straight path that the
light would otherwise have taken, so that the image on our retina, or any
other optical detector, jitters and blurs. This is also the cause of the twinkling
of the stars.