<p>I found another discussion on the same topic here: <a href="https://forum.cosmoquest.org/forum/science-and-space/space-exploration/18045-what-percentage-of-the-sky-has-hubble-imaged" rel="nofollow noreferrer">What percentage of the sky has Hubble Imaged?</a></p>
<p>Which is pretty old, but at least some numbers. According to that I gues its far bellow 10% these days.</p>
<p>It is also interesting to search <a href="https://hla.stsci.edu/hlaview.html#" rel="nofollow noreferrer">Hubble Legacy Archive</a> for &quot;footprints&quot; - but this does not cover the whole sky at once, you need to search for an object and see if there are some footprints in its area on a flashplayer-powered map.</p>

CC BY-SA 3.0
2017-07-08T14:58:15.657Z
Imagine if a Hubble-like telescope tried to take deep sky images of the whole sky. It would probably take a millennium. I think astronomers are going to have plenty of work to do for a long time.
Jack R. Woods
CC BY-SA 4.0
2017-06-30T21:10:13.030Z
2023-06-18T11:04:17.267Z
2023-06-18T11:04:17.267Z
David Komanek
<p>Physicist Casey Handmer actually made calculations and created a map of all HST observations made by April, 2022.
It turned out that the total area, that HST has covered so far is only 0.8% of the sky.  <a href="https://www.universetoday.com/155549/here-are-all-of-hubbles-observations-in-one-picture/" rel="nofollow noreferrer">Here are All of Hubble’s Observations in One Picture</a></p>

CC BY-SA 4.0
2023-06-19T11:18:08.657Z
Very interesting picture! The sinusoid-like line on the picture is the ecliptic, I guess, due to observations of planets. I also see several shortrer linear patterns, likely from observations of minor objects (asteroids, comets, etc).
Heopps
CC BY-SA 4.0
2023-06-18T06:51:16.017Z
2023-06-18T11:00:35.353Z
2023-06-18T11:00:35.353Z
Marat Musin
<p>25 years of say 16 orbits/day is a (very over-estimated) maximum of 146,000 pointings. </p>

<p>The largest instrument is the various incarnations of the optical imager with a FOV of 6 (WFPC2) to 11 (ACS) square arcminutes. Thus the absolute maximum fraction of the sky (40,000 square degrees) that can have been covered is 1 per cent. And this <em>is</em> a big overestimate, since many parts of the sky have received many repeated pointings (e.g. the Hubble deep field).</p>

CC BY-SA 3.0
2017-07-01T02:55:52.510Z
Isn't the FOV set by the mirror shape? How could different instruments have different FOV?
LocalFluff
CC BY-SA 3.0
2017-07-01T08:56:24.853Z
@LocalFluff The angular area on the sky covered by an instrument is what usually determines the field of view if, as in the HST, the focal plane is underfilled. What lies outside this is irrelevant, since no data are collected. Different detectors have different physical sizes and hence different fields of view.
ProfRob
CC BY-SA 3.0
2017-06-30T22:39:36.317Z
2017-06-30T22:39:36.317Z
ProfRob
<p>I'm curious for an estimate of how wide a field the Hubble space telescope has observed. Say, for example, how many times it has changed its pointing, and what fraction of that were revisiting the same field.</p>

CC BY-SA 3.0
2017-06-29T16:38:47.790Z
Are you talking about total area of sky observed by Hubble in its 25+ years?
Dean
CC BY-SA 3.0
2017-06-29T16:41:14.653Z
@Dean Yes. How much has this pinhole view kind of telescope been able to view of the sky during its long lifetime?
LocalFluff
CC BY-SA 3.0
2017-06-29T16:48:57.277Z
wow I wouldn't even want to guess, I know there are websites and archives for viewing all the images but I don't know any fact sheet that keeps track of number or size of fields viewed.
Dean
CC BY-SA 3.0
2017-06-29T17:34:02.053Z
I honestly wouldn't be surprised if it has viewed literally the entire sky. For example, there are plenty of surveys such as the [PHAT survey](http://www.astro.washington.edu/groups/phat/Home.html) in which Hubble has blanket mapped an entire region of the sky. That example is a rather ambitious one, but it just goes to show just how much of the sky Hubble has looked at.
zephyr
CC BY-SA 3.0
2017-06-29T21:44:34.920Z
@zephyr I highly doubt it with a FOV of 162" !! That would take over 20million individual pointings. And the PHAT survey didn't even cover the whole galaxy because its so time consuming with such a small FOV, they decided to just do one half as its fairly symmetrical.
Dean
CC BY-SA 3.0
2017-06-30T13:52:48.883Z
@Dean You're right. I guess I should've looked at the actual numbers first. It isn't really feasible for it to have covered the entire sky. Or even a large part of it.
zephyr
<observational-astronomy><hubble-telescope>
How large part of the sky has Hubble observed?
LocalFluff
# How large part of the sky has Hubble observed?

(Asked by: username_0 on 2017-06-29)

I'm curious for an estimate of how wide a field the Hubble space telescope has observed. Say, for example, how many times it has changed its pointing, and what fraction of that were revisiting the same field.

**Tags:** observational-astronomy, hubble-telescope
> **Comments:**
> **username_1**: Are you talking about total area of sky observed by Hubble in its 25+ years?  
> **username_0**: @Dean Yes. How much has this pinhole view kind of telescope been able to view of the sky during its long lifetime?  
> **username_1**: wow I wouldn't even want to guess, I know there are websites and archives for viewing all the images but I don't know any fact sheet that keeps track of number or size of fields viewed.  
> **username_2**: I honestly wouldn't be surprised if it has viewed literally the entire sky. For example, there are plenty of surveys such as the [PHAT survey](http://www.astro.washington.edu/groups/phat/Home.html) in which Hubble has blanket mapped an entire region of the sky. That example is a rather ambitious one, but it just goes to show just how much of the sky Hubble has looked at.  
> **username_1**: @zephyr I highly doubt it with a FOV of 162" !! That would take over 20million individual pointings. And the PHAT survey didn't even cover the whole galaxy because its so time consuming with such a small FOV, they decided to just do one half as its fairly symmetrical.  
> **username_2**: @Dean You're right. I guess I should've looked at the actual numbers first. It isn't really feasible for it to have covered the entire sky. Or even a large part of it.  

---

## 3 answers

### Answer by username_7 on 2017-06-30. Score: 5 | Accepted answer

25 years of say 16 orbits/day is a (very over-estimated) maximum of 146,000 pointings.

The largest instrument is the various incarnations of the optical imager with a FOV of 6 (WFPC2) to 11 (ACS) square arcminutes. Thus the absolute maximum fraction of the sky (40,000 square degrees) that can have been covered is 1 per cent. And this *is* a big overestimate, since many parts of the sky have received many repeated pointings (e.g. the Hubble deep field).

> **Comments:**
> **username_0**: Isn't the FOV set by the mirror shape? How could different instruments have different FOV?  
> **username_7**: @LocalFluff The angular area on the sky covered by an instrument is what usually determines the field of view if, as in the HST, the focal plane is underfilled. What lies outside this is irrelevant, since no data are collected. Different detectors have different physical sizes and hence different fields of view.  

---

### Answer by username_3 on 2017-06-30. Score: 3

I found another discussion on the same topic here: [What percentage of the sky has Hubble Imaged?](https://forum.cosmoquest.org/forum/science-and-space/space-exploration/18045-what-percentage-of-the-sky-has-hubble-imaged)

Which is pretty old, but at least some numbers. According to that I gues its far bellow 10% these days.

It is also interesting to search [Hubble Legacy Archive](https://hla.stsci.edu/hlaview.html#) for "footprints" - but this does not cover the whole sky at once, you need to search for an object and see if there are some footprints in its area on a flashplayer-powered map.

> **Comments:**
> **username_4**: Imagine if a Hubble-like telescope tried to take deep sky images of the whole sky. It would probably take a millennium. I think astronomers are going to have plenty of work to do for a long time.  

---

### Answer by username_5 on 2023-06-18. Score: 2

Physicist Casey Handmer actually made calculations and created a map of all HST observations made by April, 2022.
It turned out that the total area, that HST has covered so far is only 0.8% of the sky. [Here are All of Hubble’s Observations in One Picture](https://www.universetoday.com/155549/here-are-all-of-hubbles-observations-in-one-picture/)

> **Comments:**
> **username_6**: Very interesting picture! The sinusoid-like line on the picture is the ecliptic, I guess, due to observations of planets. I also see several shortrer linear patterns, likely from observations of minor objects (asteroids, comets, etc).  

---

