How Far Can the Hubble See?

The telescope is an instrument that, in principle, enables the observer to see the stars and planets with a much larger eye.

Telescopes use either a lens or a mirror.

The lens of the Hubble is 371 times wider than that of the human eye at max dilation

The lens of the Hubble is 371 times wider than that of the human eye at max dilation

The larger a telescope‟s lens or mirror, the greater its ability
to collect light, and hence the greater the distance it can see. One of
the most famous telescopes, the „Hubble‟ was developed by the
National Aeronautics and Space Administration (NASA). Its mirror
has a diameter of 2.5 meters (250 cm) directed towards the stars to
collect their light. The surface area of this mirror is large – about
49,062.5 cm2.


The following is generally how scientists think about the function of a telescope to see stars:

“The telescope with its reflecting mirror two hundred inches in diameter, serves as a sort of bucket to catch as much light as possible from a star and concentrate it on
film: it could pick up the light of a ten watt bulb a million miles away. The purpose of the telescope is not to magnify, for no matter how great the magnification,
no star would ever show up more than a point of light.”

When the human eye is compared to a telescope, it is evident
that the eye has its own objective lens that collects light. In a dark
place, the pupil of the eye becomes wide open, so that it can collect
maximum light. The circle of an open pupil in the average human
eye has a diameter of about 0.7 cm and a surface area of 0.38465
cm2. In comparison with the lens of the eye, the light-collecting
surface of the Hubble telescope‟s objective has a diameter 357.14
times larger than that of the eye. Its surface area is about 127,551
times larger than that of the eye. This means that the Hubble
telescope collects 127,551 times more light than the human eye. If all
this light were used to create brighter rather than larger images than
the naked eye sees, then the light of those images must be 127,551
times brighter than the images the naked eye sees. For this reason,
the telescope can make a star appear 127,551 times brighter.