Just thinking of these and then add on top that you have 0.5s to take the photo. This was truly a "right moment, right place, right person" kind of thing.
After ~2031, when the ISS is scheduled to be crashed into the ocean, the chances will tend to zero.
This photo is not a happy accident, though. It took careful preparation.
Let's see... it looks that at a distance of 400km we can see features of size roughly 1m (or even better). This points to resolution of 0.01 arcsecond which is fenomenal for an amateur setup.
Someone check my math but that would be like imaging the ISS at the nanometer scale from the surface of the earth.
Edit: I did it, about 25000km (for light with a wavelength of 500nm), or twice the radius of the earth. That actually suggests it could be doable with a constellation of telescopes in high orbit.
Sadly the occulder has to be smooth at sub wavelength scales, or solar system bodies could be used.
My gut says probably the same size, but the claims suggest the aragascope can actually be smaller. My gut can also imagine it depends on the distance between the aragascope and the telescope.
> can be used to achieve the diffraction limit based on the size of the low cost disk, rather than the high cost telescope mirror
This may be because of the shape of the PSF is different from the normal airy disk one.
Here is a random google result showing the spot of arago, https://www.lighttrans.com/use-cases/application/observation... -- which looks to me like it would have poor contrast but good resolution. Though I'm out of my depth so it could be nonsense. :P
Edit: Ah, yeah the graph at figure 9 in the report linked on the linked page shows something like that.
https://en.wikipedia.org/wiki/Solar_gravitational_lens
I predict in couple decades we will learn to build swarms of drone craft that we will send to the right location and they will be able to image nearby planets (one per swarm...) with at least ~10-40km per pixel if not better.
But I think there are exciting things to come up in the next decades for sure.
It wouldn't look like any telescope you might have ever seen. Once we have a candidate exoplanet we want to take a picture of we would launch a flock of free-flying solar-sail propelled satellites in such an orbit that they get yeeted away from the sun on a trajectory opposite of the target exoplanet. They would travel to the "focal plane" of the sun's gravitational lens where the exoplanet's light is smeared to a ring around the sun which they collaboratively capture. Probably one such a pass wouldn't be enough, so we would need to send such flocks multiple times, like waves following on each other.
What I love about the plan is that it is both super scifi, yet we already have all the components to make it happen if we want to.
I have also done it in front of the moon but that’s way harder because you have less light and get slower shutter speeds resulting in motion blur.
Those photos were within a couple of years of each other, obviously some time ago now.