James Webb Telescope is approximately one million miles from Earth at this very moment. It’s currently in a halo orbit in a location identified as the Lagrange L2 point.
In a perfect world, one space telescope would collect data from all the bandwidths of the electromagnetic spectrum. However, different wavelengths on the electromagnetic spectrum require other data collection and analysis equipment. Below, we tell you where James Webb Telescope is orbiting right now and why it is there.
What Kind of Telescope is the James Webb?
Telescopes collect wavelength data from the electromagnetic spectrum. Each telescope has specific wavelengths that the optics, thermal, or elemental equipment is designed to capture.
No specific space telescope covers the entire electromagnetic spectrum. Each section of the electromagnetic spectrum requires a different piece of hardware. More hardware means more weight, power requirements, and maintenance challenges.
Telescopes are designed to meet a particular scientific need. Some study exoplanets, others astronomy, others chemistry, and some dark matter or black holes. So, there’s no “one size fits all.” In the table below, we’ll look at some famous telescopes of the past decades.
|Telescope||Wavelength||Observation Target||Orbit Distance (Miles)|
|Spektr-R||Radio Waves(> 1 mm)||Collapsed stars. Effects of dark energy||1,000,000|
|Odin||Microwaves(1 mm – 25 μm)||Interstellar chemistry, star formation, and atmospheric ozone balance||22,300|
|James Webb||Infrared(25 μm – 2.5 μm)||See inside and through gas and dust clouds||1,000,000|
|James Webb||Near-Infrared(2.5 μm – 750 nm)||First light and exoplanets||1,000,000|
|Hubble||Visible Light(750 nm – 400 nm)||Galaxies, planets, stars||332|
|Astrosat||Ultraviolet400 nm – 1 nm||Neutron stars and black holes||404|
|IXPE||X-Ray(1 nm – 1 pm)||Neutron stars, nebula, and supermassive black holes||370|
|Fermi||Gamma Ray(< 10-12 m)||Black holes||342|
Some telescopes have overlapping detection capabilities. The James Webb and the Hubble have overlapping visible light spectrum capabilities. Odin and James Webb also have overlapping Infrared detection capabilities.
To understand the location of each telescope in space, we must first look at the primary scientific requirements of the Hubble and JWST.
James Webb-Space Telescope-Infrared
JWST is (primarily) an infrared telescope. The telescope’s infrared capabilities allow it to capture wavelengths created right after the big bang. Let’s compare the capabilities of the James Webb Space Telescope to the Hubble Space Telescope to understand better how the JWST Infrared capabilities make a difference.
Imagine we’re standing on a street corner. A car is parked right in front of us. The driver rev’s the engine to 5000rpm on the tachometer and holds it there. We hear the sound of the engine and the pitch of the machine as its runs. Because the car is stationary, the sound we hear travels away from the car in all directions equally.
Imagine the same car speeding towards us at 50mph, with the tach at 5,000 rpm. We can hear the engine’s pitch as the vehicle approaches our position. Basically, the engine pitch is different from what we heard when the car was parked in front of us, with the same intensity of RPMs.
The soundwaves are compressed in front of the car, and the pitch is higher as the vehicle approaches our position. Sound waves are stretched in the car’s rear, and the pitch is lower when the automobile passes our position.
Compressed wavelengths are shorter and closer to blue (in color) on the electromagnetic spectrum. Elongated, or stretched wavelengths, are longer on the electromagnetic spectrum, so they’re red (in color.) The Doppler Effect principles help explain Redshifting and Blueshifting.
Redshifting and Blueshifting
As light travels through space, the wavelength of the light changes, stretching or compressing. The stretching or compressing is known as Redshifting and Blueshifting.
In Redshifting, an object (like a galaxy, blackhole, or exoplanet) is moving “away” from us, and the wavelength of the light is stretched towards the red end of the visible light spectrum, around 700nm.
In Blueshifting, an object is moving “towards” us, like the Andromeda Galaxy, or Barnard’s Star, the wavelength of light is compressed toward the blue end of the visible light spectrum, around 400nm.
Looking at Redshifting and Blueshifting from a wavelength perspective makes them easier to understand. The same understanding applies to the other non-visible wavelengths on the electromagnetic spectrum.
All wavelengths are stretching and compressing, be they gamma rays, microwaves, visible light, infrared or radio waves. The human eye can only “see” the shift happening with our eyeballs in the visible section of the electromagnetic spectrum.
Big Bang Theory
Approximately 13.8 billion years ago, a massive explosion created the universe. The explosion is known as the Big Bang. The Cosmos, as we know it today, is expanding “out” or “away” from the center of that explosion. The wavelengths detected will be primarily Redshifted.
The Hubble instrumentation can detect wavelengths in a narrow range of the electromagnetic spectrum. As light transitions (stretches or elongates) from the visible spectrum to the infrared spectrum of the electromagnetic spectrum due to Redshifting, the Hubble instrumentation can no longer detect lightwaves that are outside its capabilities.
Configured with instrumentation for the infrared wavelengths, the JWST can detect Redshifted electromagnetic wavelengths that the Hubble isn’t able to detect.
Where Is The James Webb Telescope Orbiting Now?
JWST and the Hubble are far away from each other! With a good backyard telescope, you might have a (slim) chance to see the Hubble through your lens. However, you cannot locate the James Webb Telescope location in the night skies, even with a good backyard telescope!
- Where is the James Webb Telescope location right this second?
- What is the James Webb Telescope viewing right now?
- The JWST wavelength electromagnetic spectrum data collection is different than the Hubble.
- The Hubble is “aimed” at a target, and data is collected from the target.
- The JWST can collect data from multiple objects at the same time.
JWST Parallel Observations
The JWST can collect data from multiple instruments simultaneously. But…..just because you can collect data simultaneously doesn’t mean you should! Will your data collection impact my data collection?
Fun Fact: Will your project collect so much data that needs to be sent to the Earth for you to analyze that we cannot download my data to Earth? The JWST can store 65 GB of data. There are two daily “windows” for downloading data to Earth. Each Earth data dump is four hours, and about 28 GB of data can be transmitted. We have limited bandwidth for data collection and data transmission.
Will data collection from the instrumentation you use impact data collection from the equipment? We’re using:
- (Near Infrared Camera (NIRCam)
- Near-Infrared Spectrograph (NIRSpec)
- Mid-Infrared Instrument (MIRI)
- Fine Guidance Sensor/ Near InfraRed Imager
- Slitless Spectrograph (FGS-NIRISS)
What is the James Webb Telescope Location?
It’s a tricky question as there are two possible answers.
- The JWST is in a halo orbit in the L2 area. One full rotation around the L2 Lagrange area is completed every six months.
- The JWST is also in orbit around the sun.
A Lagrange position is a location where the gravitational forces balance out between two massive orbiting bodies.
As a result of the gravitational forces, the JWST is relatively stationary. Smaller objects, like telescopes, will remain within the “sweet spot” and stay in the Lagrange position. There are currently three other telescopes in the L2 Lagrange.
Do all planets have Lagrange positions?
Absolutely! Each planet has its own Lagrange position in our solar system. (We’re all about the Earth-Sun Lagrange position.)
How many Lagrange positions does each planet have?
Each planet in our solar system has five Lagrange positions.
- In the diagram above, positions L4 and L5 are the most stable.
- Park a telescope here, and it will (literally) stay put without needing any course corrections. If the telescope wanders a bit, gravity will tug it back to the location where it landed/arrived.
- Unfortunately, the telescope will also collect heat from the sun and the Earth.
- For this purpose, the instrumentation must be extremely cold, so there are better locations than this one.
- L1, L3
- Both locations have too much background heat from Earth for accurate instrument measurements. Colder is better.
- The JWST’s position, in relationship to Earth, provides thermal stability.
- JWST will “wander” a bit, but small rockets will thrust every three weeks to keep the telescope in a halo orbit around L2.
- The JWST will complete a single halo orbit of the L2 area every six months. The process will repeat.
- The halo orbit brings the JWST “out” from behind the Earth’s shadow to recharge its batteries through solar panels and to transmit data back to Earth.
The image featured at the top of this post is ©Dima Zel/Shutterstock.com.