With
the Hubble Deep Field
Your task is to estimate how many galaxies
there are in the universe.
The Hubble Deep Field covers an area of 1 30millionth
of the sky. This is equivalent to the
area of sky that would be hidden behind the queen’s eye of a 5 pence piece when
held at arms length.
Read the following text alongside the presentation
here. (Open both windows & alt-tab between them if possible.)
The first image that you see in the presentation
is an animation showing where in the sky the Hubble Deep Field is, to start it
click anywhere on the image.
The Hubble Deep Field is made up of images
from 4 cameras. The Wide Field and
Planetary Camera 2, used to take the deep field image, is actually 4 cameras
that look at adjacent pieces of the sky.
The 3 wide field cameras are labeled A, B and C. The planetary camera, which provides more
detail of a smaller field is labeled PC.
The resulting four separate pictures are combined, like tiles, to create
a mosaic.
For the purposes of this activity the area labeled PC has not been factored into the calculations.
The presentation goes on to show how we
will find the number of galaxies in the universe without having to count all of
them, thankfully!
Why does the Hubble Deep Field look back
in time? Find out
here.