we live in a universe of unimaginable
scale and almost incomprehensible beauty
how is the light from stars galaxies and
nebulae fashioned into the spectacular
images that are so inspired us over the
years
this is the hubblecast
news and images from the nasa/esa Hubble
Space Telescope traveling through time
and space with our host dr. J aka dr.
Joe Liske ax
welcome to the whole car you have a look
at these beautiful Hubble images and
wonder how they were made
what exactly happens after the faint
light from distant objects detected by
Hubble how are these cosmic photons
captured in space transformed into the
glorious color images down here on your
wall or your computer screen on a clear
night when you look up into the heavens
we can see the light from thousands of
stars arise a fantastic detectives but
in reality they're actually very limited
they aren't sensitive enough to peer out
very fine to space also we can only see
visible light but not ultraviolet or
infrared light like Hubble can that's
why for professional astronomers the
Hubble Space Telescope is such an
exciting tool to probe the universe
sitting at its vantage point six hundred
kilometres above the earth bubble is a
window on the universe the journey to
make a Hubble image begins when light
from a distant object starts on its way
towards us after traveling across the
vast distances of space it is captured
by Hubble with its two point four meter
wide mirror the light is then sent to
one of Hubble's several cameras where
the photons are turned into an
electrical charge by a CCD chip rather
similar to the ones in digital cameras
the advanced camera for surveys for
example contains over 16 million picture
elements or pixels these act as
miniature buckets to collect the light
the camera then reads out how much light
has been captured in each bucket the
charge within each of the pixels and
outputs an image this readout is then
being back to the earth as a series of
encoded numbers that are stored in
archives in the US and Europe
Hubble's cameras image the universe
through different filters like this one
these select specific wavelengths of
light that are characteristic of
different physical processes which may
be going on in different parts of
distant galaxies and nebulae each of
these filters results in a single
grayscale image which is then assigned a
color this color is usually chosen to
more or less correspond to the actual
color of the filter although this is not
always true anywhere between two and six
of these images are then combined to
create the final color image take this
view of the colliding attending galaxies
Hubble image this merging pair through
red green and blue filters to review the
different components inside the galaxies
for example the red light is coming from
old stars and growing hydrogen gas while
the blue light is showing the violence
star formation triggered by the cosmic
collision the red green and blue images
are then combined to create the final
multicolor image one of the challenges
in making images is that there's a huge
range of brightness in nature from faint
two bright objects and astronomical
images are so rich information that our
eyes and computer screens cannot show
their full content nature can be
difficult to capture in a single
photograph and most of us have
encountered situations like the
following imagine you try to take a
picture of a landscape when you do so
you can either capture the bride parts
of the sky or the darker parts of the
vegetation but rarely both together
the job of the image processing
specialist is to compress this range of
brightnesses together so that we can see
all the nuances image experts use the
program fits Liberator pioneered by isa
is 0 and NASA to produce a magnificent
rich image which can be interpreted by
our eyes
but is this what we would see with our
eyes if we could look through Hubble
well not really look at this image of
the cigar galaxy
this is what Hubble sees in visible
light our eyes aren't actually sensitive
enough to be able to detect the faint
light from this distant object even when
looking through a telescope the reason
why Hubble's instruments can do it is
because they can gather and add up the
light over an extended period of time
which is something our eyes can't do
furthermore some telescopes can see
wavelengths that we can't see with our
eyes this multi-wavelength view shows us
much more than our eyes or anyone
telescope can see parts of this image
were made with the chandra x-ray
observatory and x-rays and part with the
Spitzer Space Telescope in infrared
light in this episode we have seen how
the images that have amazed and
intrigued us are created
you too can have a go at making your own
images just google for Fitz Liberator
this is dr j signing off for the
hubblecast
once again Nature has surprised us
beyond our wildest imagination
history but the only person around it
doesn't have TV coverage of the food and
then you got the black up now you're
gonna be starting the TV picture is
still yes we are getting a TV picture
qty all
badly
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