Dead Horses - Discussion

Loren Pechtel wrote:

Galactic Sapper wrote:In-universe I'd expect it to be a variation of gravitic lensing, using a projected field arbitrarily large to focus light onto your instrument. Kinda the reverse of the focusing mechanism used on energy mounts.

But every gravitic lens we see is contained in something. You can whistle up a perfect lens that's totally achromatic but you're limited by the size of the device. You want a 1000m lens, you need a 1000m housing on your projector.

Not the ones that are in the sidewalls of the ships for their energy weapons. They just mysteriously work.

kzt wrote:Not the ones that are in the sidewalls of the ships for their energy weapons. They just mysteriously work.

I'm struggling to come up with any sort of gravitic lens in universe that is contained in anything material at all, given that they seem to wreck any matter they come in contact with. They're all projected a distance from the equipment used to create them.

Joat42 wrote:

Loren Pechtel wrote:How do you make those super telescopes?

VLB interferometry for example. It's trivial to deploy a bunch of drones to create a telescope with an incredible large baseline. Or use several ships and their sensors.

Loren Pechtel wrote:VLB requires knowing the positions of your sensors I believe to a fraction of a wavelength. I don't think you can know your position relative to other ships that accurately. Note that on Earth it's done in the radio band, not visible light.

VLB doesn't require knowledge of an exact position of each sensor, because they have been combining sensor data from telescopes all over the world since the 60's, it's all in how you number-crunch the data.

For optical interferometry, very large synthetic apertures is thing.

New Mexico Tech has an infrared interferometer on Mount Baldy. We are progressing to shorter wavelength. Given 2000 years, we might have Gamma Ray interferometers.

Loren Pechtel wrote:VLB requires knowing the positions of your sensors I believe to a fraction of a wavelength. I don't think you can know your position relative to other ships that accurately. Note that on Earth it's done in the radio band, not visible light.

Sure you can know the positions. You can bounce a radio wave off it and measure the time it takes to come back. Radio Detection And Ranging has been known for nearly a century... it is, after all, "RADAR". Do that with multiple sources in 3D amongst themselves and you can accurately map their positions in 3D too (triangulation, though in space would it be "tetrahedrination?").

Alternatively, you can use laser interferometry (a.k.a. "lidar"). We've been able to measure the distance to the Moon, over a light-second away, using this method for decades.

Not to mention the most recent addition to that family of interferometry detection: gravity waves. So far, our technology can't detect anything smaller than neutron stars merging. But that's limited by the size of the arms of the detectors (VIRGO has 3 km arms and LIGO has 4 km). If you're in space and can deploy arbitrarily long arms, you'll be able to detect ever fainter gravity waves. And that's with today's technology... with a better manipulation of gravity that the Honorverse has? Who knows what could be done. Not to mention that the start, the planets, and other bodies in the system are probably detectable in the Alpha Band too, which at 62c would be like measuring distance to something 62x closer.

I'd say you can measure your position inside a star system to within a mm from tens of billions of km away from the primary (a 10^16 accuracy).

kzt wrote:

Galactic Sapper wrote:In-universe I'd expect it to be a variation of gravitic lensing, using a projected field arbitrarily large to focus light onto your instrument. Kinda the reverse of the focusing mechanism used on energy mounts.

Loren Pechtel wrote:But every gravitic lens we see is contained in something. You can whistle up a perfect lens that's totally achromatic but you're limited by the size of the device. You want a 1000m lens, you need a 1000m housing on your projector.

Not the ones that are in the sidewalls of the ships for their energy weapons. They just mysteriously work.

But those are just openings, not lenses, aren't they?

ThinksMarkedly wrote:Sure you can know the positions. You can bounce a radio wave off it and measure the time it takes to come back. Radio Detection And Ranging has been known for nearly a century... it is, after all, "RADAR". Do that with multiple sources in 3D amongst themselves and you can accurately map their positions in 3D too (triangulation, though in space would it be "tetrahedrination?").

Alternatively, you can use laser interferometry (a.k.a. "lidar"). We've been able to measure the distance to the Moon, over a light-second away, using this method for decades.

Because we left reflectors up there. Without them you need to use a huge amount of power. Remember, radar in the Honorverse is only good to the million km range or so and you're making quite a beacon of yourself by doing so.

Galactic Sapper wrote:

kzt wrote:Not the ones that are in the sidewalls of the ships for their energy weapons. They just mysteriously work.

I'm struggling to come up with any sort of gravitic lens in universe that is contained in anything material at all, given that they seem to wreck any matter they come in contact with. They're all projected a distance from the equipment used to create them.

The lens is generated by something that's around it.

Joat42 wrote:VLB doesn't require knowledge of an exact position of each sensor, because they have been combining sensor data from telescopes all over the world since the 60's, it's all in how you number-crunch the data.

For optical interferometry, very large synthetic apertures is thing.

And we don't know exactly where those telescopes are relative to each other???

Loren Pechtel wrote:But every gravitic lens we see is contained in something. You can whistle up a perfect lens that's totally achromatic but you're limited by the size of the device. You want a 1000m lens, you need a 1000m housing on your projector.

Not the ones that are in the sidewalls of the ships for their energy weapons. They just mysteriously work.[/quote]

But those are just openings, not lenses, aren't they?[/quote]

For missiles yes, for energy weapons, the sidewall forms the outer lens.