Several ways to 1000-meter space telescopes

Currently there are some 30 and 40 meter optical ground based telescopes under construction. The largest mirror for a space telescope is still the Hubble Space Telescope. The 6.5 meter James Webb telescope has been delayed. James Webb has 18 hexagon segments and weighs about 6500 kilograms.

more…

Tau.Neutrino said:

Several ways to 1000-meter space telescopes

Currently there are some 30 and 40 meter optical ground based telescopes under construction. The largest mirror for a space telescope is still the Hubble Space Telescope. The 6.5 meter James Webb telescope has been delayed. James Webb has 18 hexagon segments and weighs about 6500 kilograms.

more…

There are about four ways 1000 meter (kilometer) scale space telescopes could be made in the next two decades.

1. Space bubble telescope
2. Self-assembled modular telescopes
3. Spider-fab in space construction
4. Giant lunar space telescope construction

Nice.

Going to longer frequencies makes fabrication of larger telescopes easier and more necessary.

With radio telescopes I once looked into the possibility of making a space telescope 700,000,000,000 metres in diameter.

5. Scrunchie.

mollwollfumble said:

Tau.Neutrino said:

Several ways to 1000-meter space telescopes

Currently there are some 30 and 40 meter optical ground based telescopes under construction. The largest mirror for a space telescope is still the Hubble Space Telescope. The 6.5 meter James Webb telescope has been delayed. James Webb has 18 hexagon segments and weighs about 6500 kilograms.

more…

There are about four ways 1000 meter (kilometer) scale space telescopes could be made in the next two decades.

1. Space bubble telescope
2. Self-assembled modular telescopes
3. Spider-fab in space construction
4. Giant lunar space telescope construction

Nice.

Going to longer frequencies makes fabrication of larger telescopes easier and more necessary.

With radio telescopes I once looked into the possibility of making a space telescope 700,000,000,000 metres in diameter.

How’s that going?

Peak Warming Man said:

mollwollfumble said:

Tau.Neutrino said:

Several ways to 1000-meter space telescopes

Currently there are some 30 and 40 meter optical ground based telescopes under construction. The largest mirror for a space telescope is still the Hubble Space Telescope. The 6.5 meter James Webb telescope has been delayed. James Webb has 18 hexagon segments and weighs about 6500 kilograms.

more…

There are about four ways 1000 meter (kilometer) scale space telescopes could be made in the next two decades.

1. Space bubble telescope
2. Self-assembled modular telescopes
3. Spider-fab in space construction
4. Giant lunar space telescope construction

Nice.

Going to longer frequencies makes fabrication of larger telescopes easier and more necessary.

With radio telescopes I once looked into the possibility of making a space telescope 700,000,000,000 metres in diameter.

How’s that going?

I’d have to have a look to see whether I wrote it up as an unpublished article. I’d also like to rethink the array spacing a bit, to see if I can reduce the number of array elements by making it “stochastically compact” which is another way of saying “leaving random holes”.

A space telescope array extendind all the way out to Jupiter’s orbit, 700,000,000,000 metres didn’t look feasible in the short term. Out to the Moon’s orbit, 385,000,000 metres in diameter, looks easy. Out to the Earth’s orbit, 100,000,000,000 metres in diameter looks intiguingly possible, but leaves a few gaps that I haven’t yet figured out how to plug.

mollwollfumble said:

Peak Warming Man said:

mollwollfumble said:

There are about four ways 1000 meter (kilometer) scale space telescopes could be made in the next two decades.

1. Space bubble telescope
2. Self-assembled modular telescopes
3. Spider-fab in space construction
4. Giant lunar space telescope construction

Nice.

Going to longer frequencies makes fabrication of larger telescopes easier and more necessary.

With radio telescopes I once looked into the possibility of making a space telescope 700,000,000,000 metres in diameter.

How’s that going?

I’d have to have a look to see whether I wrote it up as an unpublished article. I’d also like to rethink the array spacing a bit, to see if I can reduce the number of array elements by making it “stochastically compact” which is another way of saying “leaving random holes”.

A space telescope array extendind all the way out to Jupiter’s orbit, 700,000,000,000 metres didn’t look feasible in the short term. Out to the Moon’s orbit, 385,000,000 metres in diameter, looks easy. Out to the Earth’s orbit, 100,000,000,000 metres in diameter looks intiguingly possible, but leaves a few gaps that I haven’t yet figured out how to plug.

OK, let’s do some maths. Whether anything like this is possible depends on just how “compact” is “compact”. Consider the following, space telescopes at positions
0, 1, 3, 7, 15, 31, 63, 127, 255, … on the real number line where each number is twice the previous number plus 1. Scaling number 1 to be 100 metres gives telescope spacing for an array in one dimension. For n = 0, 1, 2, 3, 4, … these numbers are 2^n – 1 which is close enough to 2^n for large n.

Take the square root of that to get telescope distances from the centre for a 2-D array. Or take the cube root to get telescope distances from the centre for a 3-D array. So the spacing in 3-D is 2^(n/3).

A space array the equivalent of 700,000,000,000 metres in diameter would require n telescopes (space and ground) with 2^(n/3) = 700,000,000,000 / 100.

Solving for n gives n = 100 radio telescopes. So less than 100 launches needed to put the less than 100 space telescopes in the array into place. Not impossible.

Peak Warming Man said:

mollwollfumble said:

Tau.Neutrino said:

Several ways to 1000-meter space telescopes

Currently there are some 30 and 40 meter optical ground based telescopes under construction. The largest mirror for a space telescope is still the Hubble Space Telescope. The 6.5 meter James Webb telescope has been delayed. James Webb has 18 hexagon segments and weighs about 6500 kilograms.

more…

There are about four ways 1000 meter (kilometer) scale space telescopes could be made in the next two decades.

1. Space bubble telescope
2. Self-assembled modular telescopes
3. Spider-fab in space construction
4. Giant lunar space telescope construction

Nice.

Going to longer frequencies makes fabrication of larger telescopes easier and more necessary.

With radio telescopes I once looked into the possibility of making a space telescope 700,000,000,000 metres in diameter.

How’s that going?

Recalculating.

Out to about Moon’s orbit. Telescope array diameter 700,000 km.
Requires 18 space radio-telescopes.

Out to about Jupiter’s orbit. Telescope array diameter 1,540 million km.
Requires 51 space radio-telescopes.

That’s quite good. My previous estimate was 100 space radio telescopes to 700 million km.
I’d bolster that up with a few more.

Fifty one 100-metre diameter telescopes has a smaller total surface area, and therefore is easier to build, than a single 1000-metre diameter space telescope.

See link in OP for my comment about a scrunchie telescope (if they’ve posted it).

How Do You Take a Picture of a Black Hole? With a Telescope as Big as the Earth

Gravity becomes a foaming sea of riptides. Blue stars that make our sun look like a marble go slingshotting past at millions of miles per hour. Space becomes a bath of radiation; atoms dissolve into a fog of subatomic particles. And near the core, that fog forms a great glowing Frisbee that rotates around a vast dark sphere. This is the supermassive black hole at the core of the Milky Way, the still point of our slowly rotating galaxy. We call it Sagittarius A*, that last bit pronounced “A-star.” The black hole itself is invisible, but it leaves a violent imprint on its environment, pulling surrounding objects into unlikely orbits and annihilating stars and clouds of gas that stray too close. Scientists have long wondered what they would see if they could peer all the way to its edge. They may soon find out.

Ian said:

How Do You Take a Picture of a Black Hole? With a Telescope as Big as the Earth

Gravity becomes a foaming sea of riptides. Blue stars that make our sun look like a marble go slingshotting past at millions of miles per hour. Space becomes a bath of radiation; atoms dissolve into a fog of subatomic particles. And near the core, that fog forms a great glowing Frisbee that rotates around a vast dark sphere. This is the supermassive black hole at the core of the Milky Way, the still point of our slowly rotating galaxy. We call it Sagittarius A*, that last bit pronounced “A-star.” The black hole itself is invisible, but it leaves a violent imprint on its environment, pulling surrounding objects into unlikely orbits and annihilating stars and clouds of gas that stray too close. Scientists have long wondered what they would see if they could peer all the way to its edge. They may soon find out.

That’s a point. Just because we can’t see Sagittarius A-star with a telescope now, doesn’t mean that we couldn’t see it with a better telescope.

> the Event Horizon Telescope (E.H.T.) … In the late 1990s, the astrophysicists Heino Falcke, Fulvio Melia and Eric Agol, motivated by a new generation of radio telescopes then under construction, decided to see whether there were any chance of seeing Sagittarius A*’s silhouette from Earth. They ran Bardeen’s equations through software that predicted how light would travel in the warped space-time around a black hole, and they concluded that with an Earth-size collection of radio telescopes, all of them operating at the highest frequencies of the radio spectrum, all of them simultaneously observing Sagittarius A*, one would see a dark circle ten times larger than the event horizon. At the edge of this circle, light rays would be trapped, tracing a glowing ring. Inside this ring, darkness. Sagittarius A* should cast a shadow.

The SKA fits that description, both big and high frequency. Other Earth-size radio telescopes (such as the whole Earth telescope) only operate at lower frequencies.

> It’s possible we’ll encounter what Doeleman calls the nose-of-God scenario, in which an unmistakable image of the black hole shadow easily and quickly comes into focus.

The Great Green Arkleseizure

:)