APOD: Solar System Family Portrait (2024 Jul 13)

[APOD Robot]

Solar System Family Portrait

Explanation: In 1990, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. In it, Voyager's wide-angle camera frames sweep through the inner Solar System at the left, linking up with ice giant Neptune, the Solar System's outermost planet, at the far right. Positions for Venus, Earth, Jupiter, Saturn, Uranus, and Neptune are indicated by letters, while the Sun is the bright spot near the center of the circle of frames. The inset frames for each of the planets are from Voyager's narrow-field camera. Unseen in the portrait are Mercury, too close to the Sun to be detected, and Mars, unfortunately hidden by sunlight scattered in the camera's optical system. Closer to the Sun than Neptune at the time, small, faint Pluto's position was not covered. In 2024 Voyager 1, NASA’s longest-running and most-distant spacecraft, is some 15 billion miles away, operating in interstellar space.

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[shaileshs]

I wonder, after Voyager did it (famous "pale blue dot"), what's the reason NASA didn't feel like instructing any other space shuttle in last 50+ years - sent to other planets and asteroids and comets - to look back and take another (better resolution, different angle/perspective/distance) picture of mother Earth ? I can't imagine positioning/repositioning camera is a big deal at all and being time consuming or someone thinking it's useless/waste of time/efforts/money. I don't see any obvious thing that prevented and still prevents NASA from doing that. Am i missing something obvious ?

[zendae]

I imagine they never did it because Carl wasn't around to tell them to. They had no interest in doing so the first time; NASA as a body is science-oriented, and finance-oriented as a necessity, not romantically oriented. The space-faring astronauts themselves had no choice but to become emotionally and romantically involved when being directly faced by the incredible experience, one that the majority of NASA personnel never had. But the good Doctor saw everything from the "30,000 ft view" (so to speak), and we all remain forever blessed by his existence, and in more ways than just this.

It's merely my own little, uh, theory. But even if it is incorrect, it's not a bad one.

[johnnydeep]

Uh, a "60 frame mosaic"? I count only 38. Also, just to be clear, the only object actually visible in any of these frames (other than the insets) is the Sun, which is the large bright spot near the center of the arc of frames, and whose bright rays appear in other nearby frames. Correct?

[johnnydeep]

I wonder, after Voyager did it (famous "pale blue dot"), what's the reason NASA didn't feel like instructing any other space shuttle in last 50+ years - sent to other planets and asteroids and comets - to look back and take another (better resolution, different angle/perspective/distance) picture of mother Earth ? I can't imagine positioning/repositioning camera is a big deal at all and being time consuming or someone thinking it's useless/waste of time/efforts/money. I don't see any obvious thing that prevented and still prevents NASA from doing that. Am i missing something obvious ?

Well, Cassini did it in 2013. From https://www.thorntonweather.com/blog/as ... iles-away/

In this rare image taken on July 19, 2013, the wide-angle camera on NASA’s Cassini spacecraft has captured Saturn’s rings and our planet Earth and its moon in the same frame. Click to view the full size image. (NASA/JPL-Caltech/Space Science Institute)

---

I'm sure there have been others.

[Ann]

I wonder, after Voyager did it (famous "pale blue dot"), what's the reason NASA didn't feel like instructing any other space shuttle in last 50+ years - sent to other planets and asteroids and comets - to look back and take another (better resolution, different angle/perspective/distance) picture of mother Earth ? I can't imagine positioning/repositioning camera is a big deal at all and being time consuming or someone thinking it's useless/waste of time/efforts/money. I don't see any obvious thing that prevented and still prevents NASA from doing that. Am i missing something obvious ?

Well, Cassini did it in 2013. From https://www.thorntonweather.com/blog/as ... iles-away/

In this rare image taken on July 19, 2013, the wide-angle camera on NASA’s Cassini spacecraft has captured Saturn’s rings and our planet Earth and its moon in the same frame. Click to view the full size image. (NASA/JPL-Caltech/Space Science Institute)

---

I'm sure there have been others.

That's a stunning image. It brings home, somehow, the reality of Saturn and the reality of the Solar system.

And the reality of the Earth, too.

Ann

[Chris Peterson]

Uh, a "60 frame mosaic"? I count only 38. Also, just to be clear, the only object actually visible in any of these frames (other than the insets) is the Sun, which is the large bright spot near the center of the arc of frames, and whose bright rays appear in other nearby frames. Correct?

It's not a 60-frame mosaic. 60 images were collected, and 39 are composited here (note the "S" frame is two, nearly on top of each other). Each frame presented here is a thumbnail sized and largely unstretched raw image, so the planets are much too small and low contrast to see. Hence the insets with the cropped and processed planet images.

[whwiii]

forgive me if obvious, but what do "EV" and "J" stand for?

[Chris Peterson]

forgive me if obvious, but what do "EV" and "J" stand for?

"EV" labels the frame that contains both Earth and Venus. "J" labels the frame that contains Jupiter.

[johnnydeep]

Uh, a "60 frame mosaic"? I count only 38. Also, just to be clear, the only object actually visible in any of these frames (other than the insets) is the Sun, which is the large bright spot near the center of the arc of frames, and whose bright rays appear in other nearby frames. Correct?

It's not a 60-frame mosaic. 60 images were collected, and 39 are composited here (note the "S" frame is two, nearly on top of each other). Each frame presented here is a thumbnail sized and largely unstretched raw image, so the planets are much too small and low contrast to see. Hence the insets with the cropped and processed planet images.

[johnnydeep]

I wonder, after Voyager did it (famous "pale blue dot"), what's the reason NASA didn't feel like instructing any other space shuttle in last 50+ years - sent to other planets and asteroids and comets - to look back and take another (better resolution, different angle/perspective/distance) picture of mother Earth ? I can't imagine positioning/repositioning camera is a big deal at all and being time consuming or someone thinking it's useless/waste of time/efforts/money. I don't see any obvious thing that prevented and still prevents NASA from doing that. Am i missing something obvious ?

Well, Cassini did it in 2013. From https://www.thorntonweather.com/blog/as ... iles-away/

In this rare image taken on July 19, 2013, the wide-angle camera on NASA’s Cassini spacecraft has captured Saturn’s rings and our planet Earth and its moon in the same frame. Click to view the full size image. (NASA/JPL-Caltech/Space Science Institute)

---

I'm sure there have been others.

That's a stunning image. It brings home, somehow, the reality of Saturn and the reality of the Solar system.

And the reality of the Earth, too.

Ann

I just noticed that it says both the Earth and Moon are in this frame! I presume both are part of the bright blob the arrow points to, and their separation (and perhaps also the dimness of the Moon?) make them impossible to differentiate:

[Ann]

Well, Cassini did it in 2013. From https://www.thorntonweather.com/blog/as ... iles-away/

In this rare image taken on July 19, 2013, the wide-angle camera on NASA’s Cassini spacecraft has captured Saturn’s rings and our planet Earth and its moon in the same frame. Click to view the full size image. (NASA/JPL-Caltech/Space Science Institute)

---

I'm sure there have been others.

That's a stunning image. It brings home, somehow, the reality of Saturn and the reality of the Solar system.

And the reality of the Earth, too.

Ann

I just noticed that it says both the Earth and Moon are in this frame! I presume both are part of the bright blob the arrow points to, and their separation (and perhaps also the dimness of the Moon?) make them impossible to differentiate:

Click to view full size image

Could be, Johnny.

The Earth appears to have photographic diffraction spikes in this image. But the diffraction spike on the right appears to be a tiny bit "fatter" and a tiny bit brighter and differently colored than the diffraction spike on the left.

I think it should be possible to see the separation between the Earth and the Moon from Saturn. But perhaps not if you don't zoom in on the Earth-Moon system using a telescope? The Cassini image is, I take it, an "overview", not a "zoom-in"?

Ann

[johnnydeep]

That's a stunning image. It brings home, somehow, the reality of Saturn and the reality of the Solar system.

And the reality of the Earth, too.

Ann

I just noticed that it says both the Earth and Moon are in this frame! I presume both are part of the bright blob the arrow points to, and their separation (and perhaps also the dimness of the Moon?) make them impossible to differentiate:

Click to view full size image

Could be, Johnny.

The Earth appears to have photographic diffraction spikes in this image. But the diffraction spike on the right appears to be a tiny bit "fatter" and a tiny bit brighter and differently colored than the diffraction spike on the left.

I think it should be possible to see the separation between the Earth and the Moon from Saturn. But perhaps not if you don't zoom in on the Earth-Moon system using a telescope? The Cassini image is, I take it, an "overview", not a "zoom-in"?

Ann

Could be. But this amateur can't be more definitive than that!

[Chris Peterson]

The Earth appears to have photographic diffraction spikes in this image. But the diffraction spike on the right appears to be a tiny bit "fatter" and a tiny bit brighter and differently colored than the diffraction spike on the left.

Voyager I has two cameras, a narrow-field one and a wide-field one. The former is catadioptric, with its secondary mirror mounted on a lens, and the latter is a refractor. So neither camera should have diffraction spikes. The structure is probably a consequence of undersampling and processing.

[johnnydeep]

The Earth appears to have photographic diffraction spikes in this image. But the diffraction spike on the right appears to be a tiny bit "fatter" and a tiny bit brighter and differently colored than the diffraction spike on the left.

Voyager I has two cameras, a narrow-field one and a wide-field one. The former is catadioptric, with its secondary mirror mounted on a lens, and the latter is a refractor. So neither camera should have diffraction spikes. The structure is probably a consequence of undersampling and processing.

Interesting. Now what about Cassini's cameras?

[Chris Peterson]

The Earth appears to have photographic diffraction spikes in this image. But the diffraction spike on the right appears to be a tiny bit "fatter" and a tiny bit brighter and differently colored than the diffraction spike on the left.

Voyager I has two cameras, a narrow-field one and a wide-field one. The former is catadioptric, with its secondary mirror mounted on a lens, and the latter is a refractor. So neither camera should have diffraction spikes. The structure is probably a consequence of undersampling and processing.

Interesting. Now what about Cassini's cameras?

Cassini's wide field camera was a refractor. Its narrow field camera was a Ritchie-Chretien design with its secondary mirror supported by a 4-vane spider. So it should show diffraction spikes on bright enough point sources.

[johnnydeep]

Voyager I has two cameras, a narrow-field one and a wide-field one. The former is catadioptric, with its secondary mirror mounted on a lens, and the latter is a refractor. So neither camera should have diffraction spikes. The structure is probably a consequence of undersampling and processing.

Interesting. Now what about Cassini's cameras?

Cassini's wide field camera was a refractor. Its narrow field camera was a Ritchie-Chretien design with its secondary mirror supported by a 4-vane spider. So it should show diffraction spikes on bright enough point sources.

Ok, so I guess that means the four slight 90°-separated "bumps" on the image of Earth/Moon are - at least partially - due to diffraction spikes.

[Chris Peterson]

Interesting. Now what about Cassini's cameras?

Cassini's wide field camera was a refractor. Its narrow field camera was a Ritchie-Chretien design with its secondary mirror supported by a 4-vane spider. So it should show diffraction spikes on bright enough point sources.

Ok, so I guess that means the four slight 90°-separated "bumps" on the image of Earth/Moon are - at least partially - due to diffraction spikes.

Ah... missed that you were looking at a Cassini image.

[johnnydeep]

Cassini's wide field camera was a refractor. Its narrow field camera was a Ritchie-Chretien design with its secondary mirror supported by a 4-vane spider. So it should show diffraction spikes on bright enough point sources.

Ok, so I guess that means the four slight 90°-separated "bumps" on the image of Earth/Moon are - at least partially - due to diffraction spikes.

Ah... missed that you were looking at a Cassini image.