APOD: A Double Eclipse of the Sun (2015 Mar 22)

[APOD Robot]

A Double Eclipse of the Sun

Explanation: Can the Sun be eclipsed twice at the same time? Last Friday was noteworthy because part of the Earth was treated to a rare total eclipse of the Sun. But also on Friday, from a part of the Earth that only saw part of the Sun eclipsed, a second object appeared simultaneously in front of the Sun: the Earth-orbiting International Space Station. Although space station eclipses are very quick -- in this case only 0.6 seconds, they are not so rare. Capturing this composite image took a lot of planning and a little luck, as the photographer had to dodge a series of third objects that kept, annoyingly, also lining up in front of the Sun: clouds. The above superposed time-lapse sequence was taken from Fregenal de la Sierra in southern Spain. The dark disk of the Moon dominates the lower right, while the Sun's textured surface shows several filaments and, over an edge, a prominence.

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[Nitpicker]

Mister Legault has produced a number of amazing ISS transit images over the years. This is another. Makes me wonder if the people aboard the ISS had a chance to view the eclipse at all, however briefly? Do they even have windows pointing away from the Earth?

[bystander]

Mister Legault has produced a number of amazing ISS transit images over the years. This is another. Makes me wonder if the people aboard the ISS had a chance to view the eclipse at all, however briefly? Do they even have windows pointing away from the Earth?

Solar Eclipse From the International Space Station

Expedition 43 Flight Engineer Samantha Cristoforetti took a series of photographs of the March 20, 2015 solar eclipse from the International Space Station. Cristoforetti wrote, "Orbital sunrise and the #SolarEclipse... could it go any better?" ...

[Nitpicker]

Thanks bystander.

[Guest]

I'm having a difficult time proving this alignment happened. Where was ISS Mar 20 2015 9:20 UT?

[Boomer12k]

I don't call a transit an eclipse.... When Venus transits the Sun, we don't say eclipse.....

I would say a transit, and eclipse.... Eclipse is a more vast blocking of the object..... Occultation, would also be an eclipse.... But it is the total blockage from view....and we don't say, eclipse...

Still a great and interesting photo...
:---[===] *

[eaglekepr]

I'm having a difficult time proving this alignment happened. Where was ISS Mar 20 2015 9:20 UT?

Somewhere other than this photo. Using Stellarium and the location given, these photos were taken at 09:06:13/14 UTC. All three objects were aligned to match Mr. Legault's result.

[Nitpicker]

I'm having a difficult time proving this alignment happened. Where was ISS Mar 20 2015 9:20 UT?

The ISS is directly above the Earth (and the Sun and the Moon) at all times.

According to Mr Legault's page (available from the APOD caption) -- http://www.astrophoto.fr/eclipse-iss-20150320.html -- the transit happened at 09:05:04 UT. The timing can be quite sensitive to observation location on Earth (and also the ISS boost schedule, see: https://www.heavens-above.com/IssHeight.aspx).

[Nitpicker]

I don't call a transit an eclipse.... When Venus transits the Sun, we don't say eclipse.....

I would say a transit, and eclipse.... Eclipse is a more vast blocking of the object..... Occultation, would also be an eclipse.... But it is the total blockage from view....and we don't say, eclipse...

Still a great and interesting photo...
:---[===] *

Maybe a transit and two eclipses? The ISS transits across the face of the partially visible Sun, but is also eclipsed as it passes through the Moon's shadow.

[songwriterz]

Looks more like the TIE fighter vanguard of an Imperial invasion to me.

[Tszabeau]

Ssshhhh... the Moon is catching some zzzzzzzzzs.

[jalfano]

Thank you to the writers for the link to the word "clouds" - the Joni Mitchell video (Both Sides Now, live 1970) was extremely nice.

[ta152h0]

there is an equally powerful " advice " in the form of music , by Phil Collins, " Both Sides of the Story "

[Guest]

Why do the ISS images not line up?

[Nitpicker]

Why do the ISS images not line up?

Line up with what?

[Chris Peterson]

Why do the ISS images not line up?

Are you suggesting that the path of the ISS isn't straight? If so, you're probably seeing some kind of optical illusion based on all the different shapes. When I load the image in Photoshop and draw a ruler line along the path, no ISS image deviates from that line by more than a pixel or two, which is easily explained by typical daytime seeing distortion.

[Ludo]

More interestingly for me, I'd like to see more photos from the ISS looking at Earth during the eclipse..

[ta152h0]

and comets

[geckzilla]

More interestingly for me, I'd like to see more photos from the ISS looking at Earth during the eclipse..

Astro Samantha posted quite a few of them, including one of the umbra.


I think this is it: the umbra. by AstroSamantha, on Flickr


20 March solar eclipse at sunrise by AstroSamantha, on Flickr


20 March solar eclipse by AstroSamantha, on Flickr

[Ludo]

Thanks Geck for the swift reply. I've seen those but I sort of expected more from different angles given their large field of view. That one penumbra shot also intrigues me since the skies were clear over Norway where the eclipse was total. Although.. thinking a bit more about it I guess the umbra's "trail" could've passed through the arctic where the shot would've been more plausible.

Any clues on where that umbra was exactly?

[Chris Peterson]

Thanks Geck for the swift reply. I've seen those but I sort of expected more from different angles given their large field of view.

Their field isn't as large as you might think. The horizon is only a couple thousand kilometers away, and you can only see reasonable detail for probably six or seven hundred kilometers. They could easily have missed the eclipse completely.

[alter-ego]

Thanks Geck for the swift reply. I've seen those but I sort of expected more from different angles given their large field of view.

Their field isn't as large as you might think. The horizon is only a couple thousand kilometers away, and you can only see reasonable detail for probably six or seven hundred kilometers. They could easily have missed the eclipse completely.

Yes, throughout the entire 4-picture sequence (From ISS and the transit), the umbra was not yet visible. However, if the ISS ran 15 minutes later, it would crossed the terminator right on the edge of the emerging umbra. I made a composite in Google Earth showing the ISS orbital positions for each of the four pictures. Even on the 2nd pass, ISS totally missed the penumbra. Commenting on the Earth picture taken at 9:01, the umbra would not have been visible for about another 10 minutes. The visible shadow must be some shadow gradient nearing inner penumbral edge.

Google Earth, ISS Orbit and Solar Eclipse.JPG

I'm having a difficult time proving this alignment happened. Where was ISS Mar 20 2015 9:20 UT?

The ISS is directly above the Earth (and the Sun and the Moon) at all times.

According to Mr Legault's page (available from the APOD caption) -- http://www.astrophoto.fr/eclipse-iss-20150320.html -- the transit happened at 09:05:04 UT. The timing can be quite sensitive to observation location on Earth (and also the ISS boost schedule, see: https://www.heavens-above.com/IssHeight.aspx).

I found the timing of 9:05:04 is indeed duplicated by Stellarium when the correct TLE set (and maybe Stellarium version?) is used.

[geckzilla]

Cool graphic, alter-ego. I've tried doing something similar with Google Earth before and found it is not as easy as it looks. It's fun to try to place the camera at ISS altitude and see how close it is to Earth. People imagine that you can see the whole planet from up there but the orbit is actually close enough that is impossible.

[alter-ego]

Cool graphic, alter-ego. I've tried doing something similar with Google Earth before and found it is not as easy as it looks. It's fun to try to place the camera at ISS altitude and see how close it is to Earth. People imagine that you can see the whole planet from up there but the orbit is actually close enough that is impossible.

Thank you, geck.
You're absolutely right. As has been pointed out before, ISS horizon is around 1400 miles (radius). The CalSky picture shows the ISS position when the penumbral picture was taken (9:01UT). The deformed egg-shape (cyan) surrounding the ISS is the nominal visible horizon.

ISS Horizon Relative to Earth.JPG

[Roberto Capacci]

Amazing!