Goddard Glossary: Deep Field

Narration: Vivian Renkey

Transcript:

Deep field.

A tool that lets astronomers

look back in time.

A deep field is a

long-exposure image

that focuses

on a small,

specific region of the sky.

Researchers

use observations

from specialized

telescopes,

like the James Webb Space Telescope

and the Hubble Space Telescope,

to collect light

over an extended period of time.

These images can

detect objects

with extremely low light levels,

but they are

no small feat.

Deep fields require

multiple exposures,

meaning a telescope

must take several images

of the same area,

sometimes with

different filters,

to allow varied

wavelengths,

or colors,

of light to pass through.

The number

of exposures

needed varies.

Hubble's first

Deep Field

used 342 different exposures,

whereas Hubble’s eXtreme Deep Field

combined over 2000.

Capturing a

deep field

can take days, weeks,

or even months.

For Hubble,

which circles the Earth

every 97 minutes,

it can take several

orbits

of observation

to collect enough

data.

Luckily,

recent technology

is making

deep fields

easier and quicker.

In 2022,

the James Webb

Telescope

was able to capture

a deep field

with just

12.5 hours

of exposure time.

But what makes these images

so important?

Deep field

observation

allows us to study

celestial objects

too faint and

far away

to see with traditional viewing.

Scientists hope

to learn more about

early galaxy formation

and evolution.

Already,

images like

Webb’s first Deep Field

have revealed

never-before-seen galaxies,

including some

from when

our universe was

less than a billion years old.

With continued

research,

experts may be

able to

unearth the secrets

of the outer universe.