Skip to comments.Astronomy Picture of the Day - Space Station, Solar Prominences, Sun
Posted on 11/19/2023 1:50:53 PM PST by MtnClimber
Explanation: That's no sunspot. It's the International Space Station (ISS) caught passing in front of the Sun. Sunspots, individually, have a dark central umbra, a lighter surrounding penumbra, and no Dragon capsules attached. By contrast, the ISS is a complex and multi-spired mechanism, one of the largest and most complicated spacecraft ever created by humanity. Also, sunspots circle the Sun, whereas the ISS orbits the Earth. Transiting the Sun is not very unusual for the ISS, which orbits the Earth about every 90 minutes, but getting one's location, timing and equipment just right for a great image is rare. The featured picture combined three images all taken in 2021 from the same location and at nearly the same time. One image -- overexposed -- captured the faint prominences seen across the top of the Sun, a second image -- underexposed -- captured the complex texture of the Sun's chromosphere, while the third image -- the hardest to get -- captured the space station as it shot across the Sun in a fraction of a second. Close inspection of the space station's silhouette even reveals a docked Dragon Crew capsule.
For more detail go to the link and click on the image for a high definition image. You can then move the magnifying glass cursor then click to zoom in and click again to zoom out. When zoomed in you can scan by moving the side bars on the bottom and right side of the image.
Note the shadow under the station and a wee bit to the left...
Seems to me there’s no light source strong enough to cast a shadow on the sun. I suspect it’s just a cooler spot.
ISS is only about 240 miles above the earth. The sun is about 93 million miles away.
It’s probably a sunspot in white light.
It’s quite amazing to see a telescopic picture of the space station.
I’ve seen videos that amateurs have take of the ISS flying overhead.
To keep a telescope centered on something moving that fast takes some sophisticated software and equipment. Plus the H-alpha scope to capture the Sun, and then there’s processing the images…
A better mind than mine, for sure.
You win the funniest post of the day.
They can take video thus capturing a near perfect frame. They also have software which will tell the observer the exact time when ISS crosses in front of the sun at their exact longitude and latitude.
Instead of tracking ISS, they put the sun in the field of view and just wait until the scheduled transit time.
It seems to me that the dark “ISS,” is not casting a shadow.
It is the “ISS,” alone.
You are right about “no light source,” It is our beautiful Sun, the only source of warmth that is generated in our Solar System, other than the Earth’s core itself.
Maybe. But remember, from the Sun's viewpoint our Moon is always full...
I don’t think it would matter about a light source or how lit up it was. If ISS were close enough to the sun to actually cast a shadow on it’s surface, it would vaporize in the blink of an eye. Even the shadow the moon casts on the earth during a lunar eclipse, the shadow only extends so far. I would imagine even super powerful backlighting of ISS causing a shadow, would probably only project or extend out under 20 miles or so. No doubt there is a formula somewhere for determining the the length of a shadow.
Solar eclipse too☺
Yeah, you’re right. I’m thinking of night-time videos tracking the ISS across the sky.
This was shot based on planetary orbital calculations. I knew far in advance when it was going to be there. Without looking at my notes, I think the Venus transit took a couple hours to complete. The next Sun-Venus-Earth alignments will occur on Saturday December 11, 2117 and once again in 2125.
We'll probably miss the next one.☺
Yup we’ll miss it. That’s my wife’s birthday. She would be 164….
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.