<p>I thought I’d ask this question here, as I couldn’t readily find the answer looking through online resources.</p>
<p>What is the angular extent of the composite Chandra / JWST image of the Tarantula Nebula that was released in January of 2023?</p>
<p>I’d like to have a rough estimate of how big this image is, relative to the entire celestial sphere.</p>
<p><a href="https://i.sstatic.net/guNbY.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/guNbY.jpg" alt="enter image description here" /></a></p>
<p>Image source: NASA press release January 11, 2023 <a href="https://www.nasa.gov/mission_pages/chandra/images/the-enduring-stellar-lifecycle-in-30-doradus.html" rel="nofollow noreferrer">Chandra/JWST Tarantula Composite Image</a></p>

CC BY-SA 4.0
2023-03-05T12:23:42.117Z
There is a link on that page to [this page](https://chandra.harvard.edu/photo/2023/30dor/), which includes the following note: "Image is about 7.24 arcmin (360 light-years) across."
Peter Erwin
CC BY-SA 4.0
2023-03-05T14:10:40.387Z
Ah, so if the image is 7.24 arcmins across, with an aspect ratio of 630/1125 = 0.56, it must be 4.0544 arcmins high, with an area of ≈ 29.35 square arcmins (let’s call it 30 square arcmins). The celestial sphere’s surface area is approximately 150,000,000 square arcmins (ie, (4π steradians) • ((180/π)^2 square degrees per steradian) • (3600 square arcmins per square degree)). So, this little patch of glory is approximately 30/150,000,000 … or, one 5 millionth of the celestial sphere. Do I have that right? (Write it up, @Peter, if you’d like credit for the answer).
Bruce Simonson
<observational-astronomy><photography><james-webb-space-telescope><nasa><chandra>
Angular extent of this composite Chandra / JWST image of the Tarantula Nebula?
Bruce Simonson
# Angular extent of this composite Chandra / JWST image of the Tarantula Nebula?

(Asked by: username_0 on 2023-03-04)

I thought I’d ask this question here, as I couldn’t readily find the answer looking through online resources.

What is the angular extent of the composite Chandra / JWST image of the Tarantula Nebula that was released in January of 2023?

I’d like to have a rough estimate of how big this image is, relative to the entire celestial sphere.

[![enter image description here](https://i.sstatic.net/guNbY.jpg)](https://i.sstatic.net/guNbY.jpg)

Image source: NASA press release January 11, 2023 [Chandra/JWST Tarantula Composite Image](https://www.nasa.gov/mission_pages/chandra/images/the-enduring-stellar-lifecycle-in-30-doradus.html)

**Tags:** observational-astronomy, photography, james-webb-space-telescope, nasa, chandra
> **Comments:**
> **username_1**: There is a link on that page to [this page](https://chandra.harvard.edu/photo/2023/30dor/), which includes the following note: "Image is about 7.24 arcmin (360 light-years) across."  
> **username_0**: Ah, so if the image is 7.24 arcmins across, with an aspect ratio of 630/1125 = 0.56, it must be 4.0544 arcmins high, with an area of ≈ 29.35 square arcmins (let’s call it 30 square arcmins). The celestial sphere’s surface area is approximately 150,000,000 square arcmins (ie, (4π steradians) • ((180/π)^2 square degrees per steradian) • (3600 square arcmins per square degree)). So, this little patch of glory is approximately 30/150,000,000 … or, one 5 millionth of the celestial sphere. Do I have that right? (Write it up, @Peter, if you’d like credit for the answer).  

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