Sensor Ranges

[Ziggy Stardust]

I've done a search of the forums here and I also leafed through Saxton's site, but I can't seem to find any figure given for the maximum sensor range of Star Wars vessels given in any form of canon. Anyone have any sources that might indicate this? I know weapons range is on the order of 10 light seconds (or was it minutes?). Is sensor range in the same ballpark, or is it much higher?

[PainRack]

Depends on the book.... For example, Tyrant Shield has it at only 1 light year range for a dedicated sensor suite. However, that's patently too short range for any use in hyperspace, where you need ranges of tens of lightyear at the min just for safe travel.

[Ender]

I've done a search of the forums here and I also leafed through Saxton's site, but I can't seem to find any figure given for the maximum sensor range of Star Wars vessels given in any form of canon. Anyone have any sources that might indicate this? I know weapons range is on the order of 10 light seconds (or was it minutes?). Is sensor range in the same ballpark, or is it much higher?

You need to be more specific. And not confused by so much Star Trek bullshit.

This is space combat - most of your sensors are passive telescopes. Your range is "from here to the edge of the universe" provided you are willing to wait long enough for the light speed lag.

Further, you can't just say "what is the range" for active sensors either. That is dependent on the cross section of the target, the power of the ping, and the sensitivity of the reciever.

About the closest you can come is to measure the angular resolution their telescopes can achieve. But again, that will be highly variable. We don't know the placement of the telescopes on the hull, and more to the point they can quite easily use fighters, which most ships carry, to create a massivly large phased array to create an arbitrarily large baseline for whatever angular resolution you want.

Really, the limit will be a few lightseconds, as beyond that the lag will render things pointless. FTL sensors will be active and nature and thus variable to say with any degree, though one could try to hazard it out using the viral theorem and hyperspace speeds, though for that you would also need to know how fast the pulse travels and the minimum size for particulates to be a danger.

[Illuminatus Primus]

Well if there are naturally-occurring tachyons or SW subspace is anything like Trek subspace (i.e., a naturally occurring ambient aspect of the vacuum, and something that high-energy, high-mass starships would naturally influence, by direct manipulation or otherwise), there might be FTL passive sensors. Just a shot in the dark, generally I agree with Ender's analysis.

[Mange]

The CIS Shadowfeed entry, "Kuati-Neimoidian Arms Race Escalates", indicates that the minimum long sensor range is six parsec (the distance between Neimodia and Kuat). The CIS picked up a fleet of 24 Acclamators in the Kuati system employing long range scanning.

[Connor MacLeod]

As I recall a few of the NJO novels suggested very long range FTL scanning capabilities (I want to think Star by Star, or the Allston duology, or one of the Force Heretic books. And possibly Destiny's way.) I know aat least one or two of the Clone wars novels (like the medstar books) implied it as well. Might have been Dark Nest as well. Either the medstar book or the Force heretic books implied FTL ranges in parsecs (or trillions of kilometers.)

In any case, we know the main FTL sensors are tachyonic/hyperwave and subspace (I'm not sure if hyperwave and tachyonic sensors are the same, though.) and they're active sensors. That alone should imply many tens or hundreds of light years range given FTL propogation rates for comms, but its going to be limited by a lot of factors as Ender noted. More to the point, over those scales, its probably quite easy for signals to get blocked by large planetary bodies and such, which will hamper effective scanning (Active sensors will aLWAYS be line of sight.) Which would also explain why probes or scouting craft are used.

As for "passive" FTL... I dont think it would be normally "detectable" excecpt for brief periods (communications, ,enemy sensor scans, FTL transitions, ,etc. I can't think of any ships systems that would actively emit any sort of detectable signal. Perhaps computer systems might. One of the Denning short stories IIRC had mention of a computer using tachyons. If starships used computers with tachyonic/subspace signals there might be emissions and thus be detectable.

[NRS Guardian]

Cronau radiation mentioned as a byproduct of hyperjumps in the BFC trilogy might propagate at FTL speeds, and was detected by passive sensors in the BFC trilogy. So it might be possible to detect ships entering and exiting hyperspace via passive FTL sensors.

Edit: I just noticed that McLeod mentioned FTL transitions, I missed that reading his post the first time.

[Perseid]

I seem to recall an instance in the Corelian Trilogy where Wedge observed a supernova from several light weeks away, after evacuating as much of the system as possible.
I know thats not as long range as other instances, but I think he was on a frigate at the time.

[Ryan Thunder]

About the closest you can come is to measure the angular resolution their telescopes can achieve.

Maybe I'm just nitpicking, but couldn't you then define the "range" of the sensors as the distance at which the area covered by that angular resolution is equal to the largest cross-sectional area of a ship they would normally be looking for?

In other words, the distance at which they can't actually detect anything accurately enough to bother trying?

[Teleros]

That's what I'd've thought. Space may not have a horizon, but there'll come a point where the object is just so far away that interference and / or poor resolution will trump your sensors.

[Ender]

About the closest you can come is to measure the angular resolution their telescopes can achieve.

Maybe I'm just nitpicking, but couldn't you then define the "range" of the sensors as the distance at which the area covered by that angular resolution is equal to the largest cross-sectional area of a ship they would normally be looking for?

In other words, the distance at which they can't actually detect anything accurately enough to bother trying?

Yes and no. Yes, you could define it by that. But he was asking about absolute ranges for it, as in the Star Trek version of "everything in X light years". In that case the range will be dependent on the cross section of the object you are looking at. So since your sensors will be looking at any number of things, from millimeter asteroids to blue stars that method won't give you set range. Hence why it should be measured in the angular resolution, just like they do real telescopes.

[Ender]

Cronau radiation mentioned as a byproduct of hyperjumps in the BFC trilogy might propagate at FTL speeds, and was detected by passive sensors in the BFC trilogy. So it might be possible to detect ships entering and exiting hyperspace via passive FTL sensors.

Edit: I just noticed that McLeod mentioned FTL transitions, I missed that reading his post the first time.

It moves at C, Chewie timed it with the earlier detonation of some missiles so that the sensors would detect all of it at the same time to cover their jump.

That's what I'd've thought. Space may not have a horizon, but there'll come a point where the object is just so far away that interference and / or poor resolution will trump your sensors.

The distance would vary for the object, and realistically, the lightspeed lag is going to limit your detection much more then your resolution.

[Connor MacLeod]

Hyperdrives apparently DO involve tachyons in some manner, of course, so its possible the passage in and out of hyperspace involves the release of scuh. FTL locator beacons (something liek what the Vong did in Star by Star) can apparently do it (which I also believe implied hyperdrives might "leak")

I suppose its also possible that its possible to track the passage of a Starship in some fashion by detecting the effects of its passagE (not sure if this is FTL or not though, I'm just guessing)