Jump Detection Range

[MasterGwydion]

Does anyone know at what range a Jump Flash is no longer detectable? HG pg 26 says, "Far (over 5,000,000km): At these ranges, sensors can spot the signature of ships making jumps (inbound or out) and can determine only whether a contact is a ship or other similar-sized astronomical body. In either case, sensors are only able to determine the size of the contact to the nearest 10,000 tons." Okay fine, but out to what range? It is not like you are going to see a jump flash from a parsec away, so what is the max detection range?

Just for curiosity, what astronomical bodies Jump into and out of systems? lmao

Also, if you are in a sub-5,000 ton ship, does that mean that you round to zero and therefore cannot detect the ship?

 

[Condottiere]

It should vary.

If only because of stealth reasons.

 

[MasterGwydion]

It should vary.

If only because of stealth reasons.

Of course, but I need to know the baseline distances first before I can apply modifiers for size and distance.

 

[Vormaerin]

That isn't "can determine if a jump flash is from a ship or astronomical body".

You can see the jump flash AND you can only tell if an object detected exists, not whether it is a zentradi warship or oamuamua. That latter issue obviously only applies if the object enters your detection area in real space.

 

[MasterGwydion]

That isn't "can determine if a jump flash is from a ship or astronomical body".

You can see the jump flash AND you can only tell if an object detected exists, not whether it is a zentradi warship or oamuamua. That latter issue obviously only applies if the object enters your detection area in real space.

A planetoid ship was an astronomical body, so it could be both. lol I thought of that after the fact.

 

[Condottiere]

You have the initial flash.

And then you might have resonances.

Presumably, the initial flash lasts as long as the jump drive is activated and in the same dimension.

 

[Terry Mixon]

But it still doesn't address the initial question. At what range, normally and not including stealth jumping, would the flash no longer be detectable?

 

[Condottiere]

Could be both light, and gravitational wave.

Why would light be emitted?

Unless the light comes from the dimensional rift?

And would it be omnidirectional?

 

[GabrielGABFonseca]

I decided to look to Traveller 5 to try and figure this one out, but I've never really used the sensor rules before, so take with this with a grain of salt or two;

As far as I understand it, a Beowulf-class Type-A Free Trader has a maximum detection range of 500,000 Km (Space Range 7 in T5 parlance) if detecting an Adventure Class Ship, and around 2,500,000 Km (Space Range 8) if trying to detect a Battle Class Ship. Beyond that, all it will return is static. The same holds for the Type-S, which is more sensor-oriented.

As far as I can tell (and I could be wrong), no sensor that can be designed with the T5 rules could return useable data beyond Space Range 13, which equates to some 10 AU, but that's the kind of sensor that'd only be fitted onto large and dedicated spaceships, or perhaps planet-side.

If someone more acquainted with T5 than I could chime in (@Sigtrygg, perhaps?) they might be able to better help you.

 

[MasterGwydion]

I decided to look to Traveller 5 to try and figure this one out, but I've never really used the sensor rules before, so take with this with a grain of salt or two;

As far as I understand it, a Beowulf-class Type-A Free Trader has a maximum detection range of 500,000 Km (Space Range 7 in T5 parlance) if detecting an Adventure Class Ship, and around 2,500,000 Km (Space Range 8) if trying to detect a Battle Class Ship. Beyond that, all it will return is static. The same holds for the Type-S, which is more sensor-oriented.

As far as I can tell (and I could be wrong), no sensor that can be designed with the T5 rules could return useable data beyond Space Range 13, which equates to some 10 AU, but that's the kind of sensor that'd only be fitted onto large and dedicated spaceships, or perhaps planet-side.

If someone more acquainted with T5 than I could chime in (@Sigtrygg, perhaps?) they might be able to better help you.

That is cool. How about in MgT2? T5 just confuses Me.

 

[agentwigggles]

That is cool. How about in MgT2? T5 just confuses Me.

This edition doesnt care about that kind of specificity.
And the worthwhile area to be in a system, isnt often large enough to really be far out enough to hide the jump flash, without also adding in a lot of additional transit time into a system. That additional transit time, defeats any kind of surprise you may have by entering the system. The longer you're in a system, the more chances to detect you. This are gets smaller if you're including the 100d limit.
The few systems where it is large enough, like, Regina, they would also be so far away they cant meaningfully interact.
So its rather binary. You see a jumpflash. You first see all the FTL exotic particles, then you see all the luminal EMF.

 

[MasterGwydion]

This edition doesnt care about that kind of specificity.
And the worthwhile area to be in a system, isnt often large enough to really be far out enough to hide the jump flash, without also adding in a lot of additional transit time into a system. That additional transit time, defeats any kind of surprise you may have by entering the system. The longer you're in a system, the more chances to detect you. This are gets smaller if you're including the 100d limit.
The few systems where it is large enough, like, Regina, they would also be so far away they cant meaningfully interact.
So its rather binary. You see a jumpflash. You first see all the FTL exotic particles, then you see all the luminal EMF.

Basically the rules state that anything over 5,000,000km you can detect the jump flash. The Deep Space Exploration Handbook pg 23 says that Jump Flash can be detected a parsec away, but as it only travels at the speed of light, you won't actually detect it for 3 and a quarter years. So I am stumped as to how to make that useful. lol This makes the Stealth Jump thing extremely valuable.

 

[Vormaerin]

I decided to look to Traveller 5 to try and figure this one out, but I've never really used the sensor rules before, so take with this with a grain of salt or two;

As far as I understand it, a Beowulf-class Type-A Free Trader has a maximum detection range of 500,000 Km (Space Range 7 in T5 parlance) if detecting an Adventure Class Ship, and around 2,500,000 Km (Space Range 8) if trying to detect a Battle Class Ship. Beyond that, all it will return is static. The same holds for the Type-S, which is more sensor-oriented.

As far as I can tell (and I could be wrong), no sensor that can be designed with the T5 rules could return useable data beyond Space Range 13, which equates to some 10 AU, but that's the kind of sensor that'd only be fitted onto large and dedicated spaceships, or perhaps planet-side.

If someone more acquainted with T5 than I could chime in (@Sigtrygg, perhaps?) they might be able to better help you.

That's pretty much it. Jump Entrance flashes (for leaving a system) are detectable as Ship Size +4. Jump arrival flashes are Ship Size +2. This is detectable at normal ranges by electronic and visual.

Visual can detect Ship Size+4 at 8 light seconds (16 light seconds at TL 14+)
Electronics can detect Ship Size +4 at 1au at TL 12+ (half that if less than TL12).

For Ship +2, that visual at 1 light second and EMS at 16 light seconds.

flash moves at light speed, degrades by 1 magnitude per minute. Meaning the flash lasts around 10 minutes.

Mind you, you probably can't tall squat about the ship itself at that range. But you'll detect the arrival or departure. Obviously, sufficiently large bodies between you and the observer will hide you, but it'll need to be a rock that is both substantially larger than your ship *and* actually between you and the observer, since such an object would be large enough to have its own jump shadow you have to stay out of.

 

[agentwigggles]

Basically the rules state that anything over 5,000,000km you can detect the jump flash. The Deep Space Exploration Handbook pg 23 says that Jump Flash can be detected a parsec away, but as it only travels at the speed of light, you won't actually detect it for 3 and a quarter years. So I am stumped as to how to make that useful. lol This makes the Stealth Jump thing extremely valuable.

Its not that useful. Its car exhaust. It can be used to determine the traffic of a system, and it can be used to do slow observation of traffic in other polities.
Stealth Jump are very useful, in very particular circumstances.

 

[Condottiere]

I go with the premise, that in order to save money, the Confederation Navy defaults to energy inefficient jump drives, that require thirty percent more power points than the norm.

So they assume that everyone notices when they jump into a system.