Uploaded August 2026 | Updated September 2026, 2 weeks ago
So Roman and Hubble are same size telescope, but vastly different fields of view - how does that work?
If you haven’t heard of Roman, it’s NASA’s next flagship observatory, and it’s set to launch Sunday 30th August 2026. It’s named after Nancy Grace Roman, who was the chief of astronomy at NASA during the 70s where she pioneered the design and development of Hubble. So a fitting name for the Hubble telescope’s successor.
Roman is the same size as Hubble, so the mirror that collects the light is the same width, and will give us the same level of detail in images, but it’s also been designed to look at a much bigger area of sky in a single observation: its field of view is a hundred times bigger than Hubble’s!
So while all the images taken by Hubble in its 36 year lifetime have only covered less than 1% of the entire sky, Roman will cover 12% of the sky in just 17 months, a feat that would’ve taken Hubble 1700 years.
But if the two telescopes have the same size mirror, how then do you end up with such drastically different fields of view?
Well a telescope's mirror controls just two things: how much light it gathers (i.e. how faint an object it can see), and how sharp the image is.
The difference for field of view is the camera behind the mirror.
Hubble's cameras use a small number of detectors, built to stare deeply at one tiny patch of sky. And they’re old tech, designed over 20 years ago. Roman's camera though is enormous, 18 separate detectors tiled together, purpose-built to capture a huge chunk of sky in brilliant detail, all at once.
By designing it this way, Roman can do in one month, what would’ve taken the Hubble space telescope a century to do!
If you want to know more about Roman before it launches soon, check out my previous videos on why you should believe the hype, and the big science questions Roman will answer.
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: martino.freelance@gmail.com
Video produced by Marina Hui & Dr Becky Smethurst
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📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): lnk.to/DrBecky
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👕 My merch, including JWST designs, are available here (with worldwide shipping!): dr-becky.teemill.com
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🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
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🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
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👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
So Roman and Hubble are same size telescope, but vastly different fields of view - how does that work?
If you haven’t heard of Roman, it’s NASA’s next flagship observatory, and it’s set to launch Sunday 30th August 2026. It’s named after Nancy Grace Roman, who was the chief of astronomy at NASA during the 70s where she pioneered the design and development of Hubble. So a fitting name for the Hubble telescope’s successor.
Roman is the same size as Hubble, so the mirror that collects the light is the same width, and will give us the same level of detail in images, but it’s also been designed to look at a much bigger area of sky in a single observation: its field of view is a hundred times bigger than Hubble’s!
So while all the images taken by Hubble in its 36 year lifetime have only covered less than 1% of the entire sky, Roman will cover 12% of the sky in just 17 months, a feat that would’ve taken Hubble 1700 years.
But if the two telescopes have the same size mirror, how then do you end up with such drastically different fields of view?
Well a telescope's mirror controls just two things: how much light it gathers (i.e. how faint an object it can see), and how sharp the image is.
The difference for field of view is the camera behind the mirror.
Hubble's cameras use a small number of detectors, built to stare deeply at one tiny patch of sky. And they’re old tech, designed over 20 years ago. Roman's camera though is enormous, 18 separate detectors tiled together, purpose-built to capture a huge chunk of sky in brilliant detail, all at once.
By designing it this way, Roman can do in one month, what would’ve taken the Hubble space telescope a century to do!
If you want to know more about Roman before it launches soon, check out my previous videos on why you should believe the hype, and the big science questions Roman will answer.
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: martino.freelance@gmail.com
Video produced by Marina Hui & Dr Becky Smethurst
---
📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): lnk.to/DrBecky
---
👕 My merch, including JWST designs, are available here (with worldwide shipping!): dr-becky.teemill.com
---
🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
---
🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
---
👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
