1. THE JAMES WEBB SPACE TELESCOPE
The Next Generation SpaceTelescope
Jared Cohn & Jacob Gruhn
The James Webb SpaceTelescope, due to launch in 2018, will be the foremost
space telescope of the next ten years. With imaging technology geared
toward the infrared, we will be able to see further back in time than any
telescope before.The JWST will be our eye into the formation of the first stars
and galaxies, as well as into the evolution of planetary systems.

2. Mission Goals
 The JamesWebb SpaceTelescope is the
successor to the Hubble SpaceTelescope
 Utilizing advances in imaging and computing to
accomplish goals the Hubble could not
 Goals:
 To search for the first galaxies and stars formed after
the Big Bang
 Determine how galaxies evolve over time
 Observe the formation of stars until the formation of
planets
 To measure the physical and chemical properties of
exoplanets and determine whether they hold the
potential to host life

3. Finding the Oldest Stars
 Because the universe is expanding, distant objects are
moving away from us at high velocities corresponding to
their distance
 𝑣 = 𝐻0 𝐷
 Light emitted from distant objects which are moving away from us
shift toward redder wavelengths (redshift)
 JWST’s instruments are geared to detecting redder
wavelengths, which Hubble was unable to do
 The primary mirror of the JWST will have 2.5 times the
diameter of the Hubble, giving it much better light gathering
ability
 With JWST’s enhanced light gathering ability and sensitivity
to infrared wavelengths, observations taken by the
telescope could date from 100 to 250 million years after the
big bang

4. Light Gathering System
 The mirror is composed of 18 semi-
rigid hexagonal segments
composed of gold-coated beryllium
 Beryllium has a very small coefficient of
expansion temperatures of 30-80KThe
mirror is composed of 18 semi-rigid
hexagonal segments
 Has a focal length of 131.4 meters
 Collecting area of 25𝑚2
 This is 5 times larger than Hubble’s
collectingarea
 f/number of 20, giving it a very small
field of view
 Allows in-depth studies of small,
distant celestial bodies 131.4 = 𝑟/2
𝑟 = 262.8 meters
“The James WebbSpace Telescope”,Gardneret. al. Page567

5. NIRCam and NIRSpec
 NIRcam detects wavelengths from .6-5μm
 Light is directed onto short and long wavelength
detectors
 Provides large field of view
 A dichroicfilter separates the incoming beam
into long and short wavelengths
 Based in principles of thin-film interference
 Layers of optical coatings with varying refractive
indices cause constructive and destructive
interference at specific ranges of wavelengths
 Features coronagraph plates whichblocksthe
light from bright objects that could interfere
with observationof a science target
 NIRSpec has a spectrograph capable of taking
the spectra of over 100 objects at once
 Contains 4 different spectrographs of varying
resolving powers
“The James WebbSpace Telescope”,Gardneret. al. Page576

6. Mid InfraRed Instrument (MIRI)
 Has a great depth of field
 Can take deep field imagery greater
than that of the HubbleSpace
Telescope
 Sensitive at 6-27μm
 This is from [visible] orange to near-
infrared
 Contains both an imager and an IFU
spectrograph
 The spectrograph has resolving power
R~3000
 Instrumentation uses a unique
cooling system to keep unit at ideal
temperature of 7K
 On board electronics calibrate and
control which filters are in
operation, slicing images into tiny
slits for greatest possible light
collection in particular resolutions
“The James WebbSpace Telescope”,Gardneret. al. Page583

7. Accomplishing the Mission
 MIRI focuses on the infrared
spectrum. This allows us to
detect heavily redshifted objects
 Able to detect objects with up to
Z=20
 Using long-slit spectra, the
JWST will be able to study
galaxies at different stages of
evolution
 The coronagraph attached to
each instrument will allow the
study of protoplanetary discs
around young stars
 The large light gathering system
will be able to detect light from
galaxies at greater distances
than Hubble ever could
http://en.wikipedia.org/wiki/James_Webb_Space_Telescope