Mapping exoplanet surfaces with solar gravitational telescope

Maybe we could try it on Jupiter first....?

Jupiter's diameter is about 11 times that of the Earth's and the Sun's diameter is about 10 times Jupiter's...

If I understood it correctly: the focal length of Jupiter would be much longer than that of the sun.

Maybe if we were lucky we could use the gravitational field of a small planet orbiting a nearby star.

There are a number of tough engineering problems. Besides surviving a close pass of the sun with a giant delicate solar sail, there is the tricky part of arriving 550 AU out within a 1.3 km location.

But wouldn't it be awesome to image an exoplanet and see city lights!

Well if the lensing effect is around the planet, why couldn't we have an orbiting telescope that would gather the lensing effect as it orbited the planet at the proper angle and distance and build a picture for each rotational trip...?

Interesting idea. What if the planet doing the lensing was Earth?

Most illustrations of gravitational lensing I've seen show parallel rays prior to the "lens" bending and converging to a focus after passing the "lens". Of course some bending of the rays will have occurred before the rays reach the "lens", but most of the bending will occur as the rays pass the "lens", so the magnification will be far less to a telescope orbiting the "lens".

Then, as I understand it, the plane of that orbit would have to be precisely normal to the line from the center of the "lens" to the object being studied.

The sun is the only mass we might be able to use this gravitational lensing effect to make a high-resolution telescope. With gravitational lensing, the focal point for our sun will be at 540 AU. Neptune's orbit radius is 30.1 AU. The mass of the Earth is considerably less than the sun so its focal length will be even farther than 540 AU. At any of these distances, the only thing one might be in a really slow orbit around is the sun.

You have to get to the focal point.

But the lensing effect is contained in a ring around the planet...if you had a string of cubesat's observing the ring then you could gather all the information, there is no need to go to the focal point, you can focus the gathered information into a focal point with a software program...

And all of the animals in a mirage can get a cool drink anytime they want.

The lensing effect does not increase the density of information where it occurs: there is no gain to be made by gathering data there.

That is an interesting proposal. The kinematic accuracy to attempt this is truly mind-numbing. Just think of the tiny error window needed to gravity assist between Mercury's orbit and Sol in order to be on the correct trajectory to align with the Sol and a likely planetary star system.

I can think of a few critical points not addressed that might kill this plan. While it's true that a solar sail does not require fuel to get out to 550+ AU, the ion drives proffered for steering adjustments do need something to ionize and a power source to accelerate the ions. That power source can't be solar cells at that distance from the sun. Whatever mystery power source driving those ion thrusters will presumably also power the communication of vastly more information than Voyager can communicate now.

Still, this is an intriguing idea.

Yeah, I'm thinking they would definitely need a nuclear-powered source. And maybe a magnetic sail of some sort would have a better chance of lasting for 35 years than a material sail 100 atoms thick the size of a football stadium. The slingshot past the sun is necessary to get out that far in a short amount of time.

Magnetic sail - Wikipedia

NASA has done some amazing things. Someday they might just pull this off.

https://www.universetoday.com/138141/gravitational-microlensing-method/

We have an amazing telescope. Our problem is aiming it.

Before somebody puts in an enormous effort to attempt this deep-space imaging I'd like to see an accidental Einstein ring image reconstituted as this idea claims. I realize a controlled raster scanning cannot happen with an accidental alignment.

Here is a Hubble capture of an Einstein ring. What can this fuzzy ring with four dots tell us after imaging reconstruction?

Really interesting! Thanks!

A neutron star seems like it would be the best bang-for-buck Einstein ring telescope...

..."Some of the closest known neutron stars are RX J1856.5−3754, which is about 400 light-years from Earth, and PSR J0108−1431 about 424 light years.^[66] RX J1856.5-3754 is a member of a close group of neutron stars called The Magnificent Seven. Another nearby neutron star that was detected transiting the backdrop of the constellation Ursa Minor has been nicknamed Calvera by its Canadian and American discoverers, after the villain in the 1960 film The Magnificent Seven. This rapidly moving object was discovered using the ROSAT/Bright Source Catalog.

Neutron stars are only detectable with modern technology during the earliest stages of their lives (almost always less than 1 million years) and are vastly outnumbered by older neutron stars that would only be detectable through their blackbody radiation and gravitational effects on other stars."...

Maybe there is a neutron star focal point that is closer to Earth than 650 au or 6.042e+10 miles....?

..."Additionally, the star loses a lot of mass in the process and winds up only about 1.5 times the Sun’s mass. But all that matter has been compressed to an object about 10 miles (16 kilometers) across. A normal star of that mass would be more than 1 million miles (1.6 million km) across. "....

What if we had one gravitational lens at the focal point of another gravitational lens...? What if we had a line of them across the universe, would we be able to see forever?

https://www.telescope-optics.net/eyepiece1.htm

https://www.atmos-software.it/Atmos8_9.html