Question

Galaxies are millions of light years away and we are able to capture images through cameras in telescopes. Do scientists leave the telescope pointing at space until the galaxies slowly start to appear? Or do they zoom in into space?

Answer 1

See explanation...

Explanation:

A few galaxies are bright enough to see something of them with the naked eye. For example, in the northern hemisphere we can see the centre of the Andromeda Galaxy (about `2.5` million light years away) as a fuzzy patch of light.

In order to capture a decent image with a camera attached to a telescope, the telescope is kept pointing at the same part of the sky using a right ascension drive. This motorised mechanism cancels out the effect of the rotation of the Earth. If the sky is clear enough and there is sufficiently little light pollution, a long exposure can be used to capture faint details of a distant galaxy.

Locations in the sky are referenced using one of a small number of coordinate systems. Once you have a coordinate system, you can systematically point your telescope at different patches of the sky to catalogue what you can see. For example, the Mount Palomar `200` inch telescope was used to produce a star atlas in the 1950's consisting of `935` pairs of `14` inch photographic plates, recording stars and galaxies down to magnitude `20`.

Nowadays we know where many galaxies can be found, so can immediately point telescopes in the right direction to observe them.

Concerning "zooming in", it is interesting to note that nature sometimes gives us a helping hand to see some of the most distant galaxies. Sometimes clusters of galaxies can form a gravitational lens, magnifying stars and galaxies beyond them.