Starship Asterisk*

A Solar Eclipse from the Moon

Explanation: Has a solar eclipse ever been seen from the Moon? Yes, first in 1967 -- but it may happen again next week. The robotic Surveyor 3 mission took thousands of wide angle television images of the Earth in 1967, a few of which captured the Earth moving in front of the Sun. Several of these images have been retrieved from the NASA archives and compiled into the above time-lapse video. Although the images are grainy, the Earth's atmosphere clearly refracted sunlight around it and showed a beading effect when some paths were blocked by clouds. Two years later, in 1969, the Apollo 12 crew saw firsthand a different eclipse of the Sun by the Earth on the way back from the Moon. In 2009, Japan's robotic Kaguya spacecraft took higher resolution images of a similar eclipse while orbiting the Moon. Next week, however, China's Chang'e 3 mission, including its Yutu rover, might witness a new total eclipse of the Sun by the Earth from surface of the Moon. Simultaneously, from lunar orbit, NASA's LADEE mission might also capture the unusual April 15 event. Another angle of this same event will surely be visible to people on Earth -- a total lunar eclipse.

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I'll be impressed if LADEE can return an image of the eclipse whilst in its death throes.

Does anyone know if there are any eclipse-suitable cameras still working on the Chang'e 3 lander or rover? I can't say I've seen a lot of images from the mission of late, but I've not been following too closely since the rover reported its malfunction.

Oh, how neeeeaaaaat.....

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Nitpicker wrote:
I'll be impressed if LADEE can return an image of the eclipse whilst in its death throes.

The solar powered spacecraft might just be 'done in' by the eclipse:

• 1) around the moon 2) with an eclipse 3) by Miss Scarlet.

Nitpicker wrote:
Does anyone know if there are any eclipse-suitable cameras still working on the Chang'e 3 lander or rover? I can't say I've seen a lot of images from the mission of late, but I've not been following too closely since the rover reported its malfunction.

The rover Yutu can't rove but everything else is in working order so far as I know.

Beautiful.

I had to pull the main gif off the page to view it. I probably have something disabled in my browser, but nothing that I know of that interferes with an animated gif. Anyone else?

HellCat wrote:I had to pull the main gif off the page to view it. I probably have something disabled in my browser, but nothing that I know of that interferes with an animated gif. Anyone else?

Yes. I've had issues with animated GIFs where they only play once and don't repeat properly (which is what this APOD is doing for me... I reload the page and it plays through once and stops). Same thing happens with animated GIFs I've uploaded to the Asterisk.

Chris Peterson wrote: Yes. I've had issues with animated GIFs where they only play once and don't repeat properly (which is what this APOD is doing for me... I reload the page and it plays through once and stops). Same thing happens with animated GIFs I've uploaded to the Asterisk.

This time, I've set the animated GIF to run once and then stop. Usually I let an animated GIF run three times and stop but here it is relatively hard to tell the last frame from the first, so to be clear what the entire short sequence is, it runs once. I almost never put animated GIFs on an infinite loop because I frequently keep my browser open to APOD and if the APOD has motion after a minute or so I find it REALLY ANNOYING. So rather than encourage people to leave the page, the GIF runs for a limited time. I apologize to those who find this inconvenient.

- RJN

RJN wrote:This time, I've set the animated GIF to run once and then stop. Usually I let an animated GIF run three times and stop but here it is relatively hard to tell the last frame from the first, so to be clear what the entire short sequence is, it runs once. I almost never put animated GIFs on an infinite loop because I frequently keep my browser open to APOD and if the APOD has motion after a minute or so I find it REALLY ANNOYING. So rather than encourage people to leave the page, the GIF runs for a limited time. I apologize to those who find this inconvenient.

Interesting, because when I copy the GIF to my desktop and play it in my image viewer, it cycles forever (which they don't normally do when set for a single cycle).

GIFs are one of the few universal ways to distribute simple animations, but they're very old technology. I guess different viewers are a little non-uniform in how they handle them in some cases.

RJN wrote:I frequently keep my browser open to APOD and if the APOD has motion after a minute or so I find it REALLY ANNOYING.

This has been one of the great mysteries of APOD for me. Three loops is almost never enough for me. It doesn't matter much this time but usually I prefer to stare at it for about thirty seconds to one minute. If all three loops are over in 5 seconds, it's very unsatisfying. Well, now I know...

I would love it if somebody would put a camera right in the middle of the Earth-facing side of the Moon (the highlands north of Albategnius, perhaps) transmitting a live video feed of the Earth. Tune in to the Moon-Earth channel and you could watch the continents and oceans rotating in and out of view, sunrise and sunset moving across the face of the Earth, clouds developing and moving, snowpack and sea ice, etc. The Moon-Earth channel would be especially popular during lunar eclipses.

Anthony Barreiro wrote:I would love it if somebody would put a camera right in the middle of the Earth-facing side of the Moon (the highlands north of Albategnius, perhaps) transmitting a live video feed of the Earth. Tune in to the Moon-Earth channel and you could watch the continents and oceans rotating in and out of view, sunrise and sunset moving across the face of the Earth, clouds developing and moving, snowpack and sea ice, etc. The Moon-Earth channel would be especially popular during lunar eclipses.

I rather like your idea. If this did happen, I might even buy a TV set just to watch it.

LocalColor wrote:

Anthony Barreiro wrote:I would love it if somebody would put a camera right in the middle of the Earth-facing side of the Moon (the highlands north of Albategnius, perhaps) transmitting a live video feed of the Earth. Tune in to the Moon-Earth channel and you could watch the continents and oceans rotating in and out of view, sunrise and sunset moving across the face of the Earth, clouds developing and moving, snowpack and sea ice, etc. The Moon-Earth channel would be especially popular during lunar eclipses.

I rather like your idea. If this did happen, I might even buy a TV set just to watch it.

Yes, it is a nice suggestion. It makes me wonder if a continuous view back at Earth might already be available from one of the many artificial satellites orbiting our fair planet.

The location on the Moon’s near side wouldn’t matter much, as long as its site wasn’t in the zones on the Moon that move in and out of view from Earth due to lunar librations. In addition to the changes Anthony mentioned there would be changes in the position of the Earth as the Moon wobbles around, and there would also be changes in the apparent size of the Earth as the Moon moves between apogee and perigee about every 14 days.

A time laps of such a changing view of Earth from the Moon would make a nice screen saver.

Bruce

BDanielMayfield wrote:

LocalColor wrote:

Anthony Barreiro wrote:I would love it if somebody would put a camera right in the middle of the Earth-facing side of the Moon (the highlands north of Albategnius, perhaps) transmitting a live video feed of the Earth. Tune in to the Moon-Earth channel and you could watch the continents and oceans rotating in and out of view, sunrise and sunset moving across the face of the Earth, clouds developing and moving, snowpack and sea ice, etc. The Moon-Earth channel would be especially popular during lunar eclipses.

I rather like your idea. If this did happen, I might even buy a TV set just to watch it.

Yes, it is a nice suggestion. It makes me wonder if a continuous view back at Earth might already be available from one of the many artificial satellites orbiting our fair planet.

The location on the Moon’s near side wouldn’t matter much, as long as its site wasn’t in the zones on the Moon that move in and out of view from Earth due to lunar librations. In addition to the changes Anthony mentioned there would be changes in the position of the Earth as the Moon wobbles around, and there would also be changes in the apparent size of the Earth as the Moon moves between apogee and perigee about every 14 days.

A time laps of such a changing view of Earth from the Moon would make a nice screen saver.

Bruce

The closest I've seen is the view from geosynchronous weather satellites, but a geosynchronous satellite is always looking at the same terrestrial longitude, and they're too close to Earth to show the full ring of sunsets and sunrises during a lunar eclipse.

Anthony Barreiro wrote:The closest I've seen is the view from geosynchronous weather satellites, but a geosynchronous satellite is always looking at the same terrestrial longitude, and they're too close to Earth to show the full ring of sunsets and sunrises during a lunar eclipse.

Just for reference, at the surface of the Moon you can see 178.1° of the Earth's surface (99% of the full disc). From geosynchronous orbit you can see 149.6° (83% of the full disc). Sunrises and sunsets look the same from geosynchronous orbit whether the Moon is in eclipse or not.

What am I missing? I expected the earth covering the sun to look a lot bigger than the moon covering the sun. The earth in this set of images looks the same curvature and size to me as the moon does in a solar eclipse as viewed from earth.

astrokareny wrote:What am I missing? I expected the earth covering the sun to look a lot bigger than the moon covering the sun. The earth in this set of images looks the same curvature and size to me as the moon does in a solar eclipse as viewed from earth.

The Earth is a lot bigger. The difference is that when you see a solar eclipse, the light around the edge of the Moon is the Sun's corona and sometimes a bit of photosphere. In today's image, you're not seeing the Sun at all, only its light refracted and scattered off the Earth's atmosphere. The Sun is completely hidden behind the Earth.

Thank you, Chris. That clarifies it.

Chris Peterson wrote:

Anthony Barreiro wrote:The closest I've seen is the view from geosynchronous weather satellites, but a geosynchronous satellite is always looking at the same terrestrial longitude, and they're too close to Earth to show the full ring of sunsets and sunrises during a lunar eclipse.

Just for reference, at the surface of the Moon you can see 178.1° of the Earth's surface (99% of the full disc). From geosynchronous orbit you can see 149.6° (83% of the full disc). Sunrises and sunsets look the same from geosynchronous orbit whether the Moon is in eclipse or not.

I guess that would be because the satellite is in eclipse once every 24 hours.

neufer wrote:http://www.planetary.org/blogs/guest-bl ... pdate.html

Thanks Art, very informative. It sounds like these craft don't have any optical wavelength instruments to take pictures of the Earth eclipsing the Sun.