So as not to hijack the "threat and despair with sensors" thread...

It's a little embarrassing to admit, but I realized I've been thinking about and using sensors all wrong, which is part of the reason my feeble attempts at space battles have landed like a thermal detonator dud. My assumption has been that if a ship can see you, you can see it, and an ISD even at long range is going to show up on almost any ship's sensors. But that's not the case at all.

Most starting PC ships have sensors that only see things at Close range. An ISD could be setting at Medium or Short range, and the players would never know (unless they used Active sensors, and extended their range out to Short, but with only visibility in a single Fire Arc). So springing a trap on the PCs suddenly makes more sense.

What's still not clear to me is what exact information the sensors convey. If an ISD was in Short range, and you found it using Active sensors, would you just see a big blip and have to use Computers to identify it? If they were jamming you, would you need to make a contested roll?

Conversely if an ISD was at long range would they know automatically that you were there? And if so...how the heck does anybody do any smuggling without Long or Extreme range sensors?

And what else do sensors convey? Life forms? Tech levels? Planetary energy fields?

Lastly, does anyone have any examples of how they or their players have used sensors in the game?

Hmmmm, lotsa sensor questions. Just posted one thing. Sensor is kind of a broad term and without getting RL nit picky into different systems for doing things how targets detect one another could vary a great deal.

To me if I was in an ISD on patrol and we were doing piracy/smuggling suppression, system's probably have designated jump corridors. So my opinion of physics is that any given mass entering or exiting hyperspace probably gives off a pretty distinctive powerful emission. That would show up on passive scans in my mind.

IRL, without causing too much groaning, use of active sensors would typically illuminate you to everyone else, like turning on a flashlight in a dark warehouse.

What sorts of information could be conveyed would be determined greatly by range, and target emissions. An example, with passive sensors from a greater range, you might be able to tell the reactor emission difference between an ISD and a patrol boat. Class would at the least require closer range. Active sensors and the sky is the limit in my mind.

In regards to jamming and such, jamming prevents the ability to see precisely, but that's not stealth. The space cat is out of the bag at that point. Powering down and running silent is stealth.

For planets, something simple like a spectral analysis can reveal chlorophyll and complex hydrocarbons, indicating life and potentially tech levels. Radioactive isotopes in an upper atmosphere might be indicative of something. Repulsor tech and reactors also would be indicative and fairly specific in their emissions I would think. In regards to actual races, short of just using a telescope I'm a little leery of being that detailed.

I largely assume that using sensors is largely playing a computer assisted guessing game. So when you roll sensors the computer is looking at all the information it's collecting, and then presents that information to the operator along with educated guesses. This works reasonablely well and allows for things like sensor ghosts and decoy pods.

Think Hunt for Red October. The US sonar detects the catapiller drive the RO has, but mislabels it as magma displacement, but the expert sonar tech realizes the system just doens't know what it's looking at and so is defaulting back to siesmic activity.

It's utimately up to the GM, but here's my opinions on the matter and how I'd run it:

What's still not clear to me is what exact information the sensors convey. If an ISD was in Short range, and you found it using Active sensors, would you just see a big blip and have to use Computers to identify it?

Computers to operate the sensors, with results determining info presented the player. So one success might just say it's a big blip that is probably a ship. Two it's a large warship. Three it's an ISD.

If they were jamming you, would you need to make a contested roll?

No I'd do it just like int he rule book. They roll, and successes/advantage effect your difficulty. Though I would say with an advantageous failure you know immediately you're being jammed, with enough advantage you'd even know it was raspberry.

Conversely if an ISD was at long range would they know automatically that you were there? And if so...how the heck does anybody do any smuggling without Long or Extreme range sensors?

No, again, they gotta be rolling to detect you, then they gotta ID you as a threat, and have something within range. This allows for things like the players flying extremely close to a bulk frieghter to try and mask themselves, or drifting on backup batteries to try and appear like an asteroid.

I think that adjusting the difficulty per range band also makes a heck of a lot of sense. At long range you're lucky if the other ship is a speck, at close range the visual scanners can look right in the windows and see that guy playing galaga...

Also though remember that smuggling isn't just about not getting detected, it's about not getting caught. One way to make a Politico or Scoundrel fun in the smuggling trade is to put them on comms. "Oh yes sir, we'll shut down and await boarding by the inspection team. Let em know they might want to wear space suits though, a couple of our freezer units failed so the whole ship smells like six week old rotten gooberfish now. Doesn't bother me because I lost all sense of smell after a refueling accident a few years back, but the inspectors at our refueling stop yesterday spent the entire time throwing up... Oh hey you got a droid tech you can send over with the inspector? Our cleaning droid hasn't been working all month and the floor is getting crunchy in a few spots..."

And what else do sensors convey? Life forms? Tech levels? Planetary energy fields?

This is case by case and for me requires multipule rolls or a lot of advantage/success/triumph. And again it's the computers best guess plus the operators ability to interperate that info. So searching "life forms" on a planet would be the sensors determining if the atmo would support life, what kind of life and it's detectable attributes, and then looking for those attributes and making best guess about size/shape/ect. So the sensors might detect a large heat sig on the great plains, but it might come back "large herd of nerfs standing close together", or it might come back "land whale" depending on the rolls.

This is my take on it: any sensor can pick up blips up to extreme range, but communication and identification of what it is would be limited by sensor range. It still requires a check, and I'd consider making sensor checks to pick up blips at extreme range to be daunting to formidable.

So, when dropping out of hyperspace the sensor operator runs a scan, using passive sensors as its the quickest, it sweeps the surrounding area. Success means the operator would've identified anything within passive sensor range. Additional successes and/or advantages could allow for blips to be picked up beyond passive range. Alternately - and this is I guess some sort of house rule - the operator can make ... let's call it a "system scan". This is basically trying to pick up any blips in the system. The difficulty is high (remember setback dice) and results yielded should be limited to: something beyond active sensor range: could be an asteroid, a planet or a ship. Excessive successes and advantages can modify this to identify fire arc, what range band beyond active sensor range, and a rough silhouette estimate, i.e. larger than us (which could be same silhouette and larger), smaller than us (same or smaller), same as us. Any movement needs to be tracked over consecutive rounds, sort of like sonar or whatever. Anything within passive and active range can be identified much more detailed.

That's at least how I try to use it.

This means that a ISD or a bunch of pirates can lie in wait, and unseasoned heroes forget to do the sensor check... although sometimes I do use the sensors a bit like perception if any players has specified that s/he is operating that station.

Thanks, great insight and it will help my game a lot. I'm not looking to get too crunchy with it, but I basically had no parameters at all.

I think that adjusting the difficulty per range band also makes a heck of a lot of sense. At long range you're lucky if the other ship is a speck, at close range the visual scanners can look right in the windows and see that guy playing galaga...

I was thinking this myself, but the difficulty would have to be an intersection of sensor range and object range. I had been thinking something like Close sensors could actually detect items at Short range, but with Daunting or Formidable difficulty. Maybe the base rating at the furthest range of the sensor is Hard, one less is Average, two less is Easy; unless the sensor range is Close, in which case Close objects are Average.

Range is clearly a factor. With all the gobbledygook in the background EM spectrum of a solar system, things would wash each other out quickly.

Thanks, great insight and it will help my game a lot. I'm not looking to get too crunchy with it, but I basically had no parameters at all.

I think that adjusting the difficulty per range band also makes a heck of a lot of sense. At long range you're lucky if the other ship is a speck, at close range the visual scanners can look right in the windows and see that guy playing galaga...

I was thinking this myself, but the difficulty would have to be an intersection of sensor range and object range. I had been thinking something like Close sensors could actually detect items at Short range, but with Daunting or Formidable difficulty. Maybe the base rating at the furthest range of the sensor is Hard, one less is Average, two less is Easy; unless the sensor range is Close, in which case Close objects are Average.

Depends, I usually go with 1 Setback for each band beyond close, adjusted for other factors (finding an active Super Star Destroyer at long range isn't gonna be THAT hard, spotting a derelict TIE is).

Also, just to clarify something. In the case of passive sensors I don't dispute the book, so much as I see the need to have checks sometimes. So in your smuggling example, it's not that the ISD's passive sensors don't "see" the players at long range, it's that it sees so much that there is still a need for the operator to prioritize the information and recognize what is worth reporting when. The same goes for the players. A Jumpmaster's sensors can "see" things a long way out, but the players still have to look at that read out and make sure all that info coming in makes sense, and might miss the Sentinel landing craft on a landing vector because they got distracted by the asteroid that totally looks like Darth Vader riding a tricycle...

This allows for the sensor checks needed for narrative gameplay, but also allows the players to not have to roll sensors every combat round just to "see" the TIE fighters that are actively attacking them (which the sensor computer can easily "lock on, identify, and prioritize" without any noteworthy input from the operator/pilot).

Basic sensor difficulty is Easy (see sidebar/datapad page 227) for active sensor range, which is limited to one fire arc.

Passive sensors require no check it says, but I'd adjust that depending on circumstances.

Based on this, I'd modify what I posted above slightly. I'd basically allow for an active sweep, which would be a computers check at active sensor range, difficulty increased once (or twice?), plus a setback die due to the extensiveness and intensity of the task.

I'd limit check beyond active sensor range to advantages, triumphs and excessive successes. Although the aforementioned suggested house-rule thingy I'd make into an upgrade hard, or daunting (plus a setback die depending on the "terrain" of the system/area) computer check to pick up the most basic of information, i.e. if anything at all is there, no details, perhaps silhouette if you're lucky. Perhaps a power source, but not nature or power level...

If you want to know how sensors would work in space, check Project Rho.

Sure, you can make your game play as submarines in the 80's where the operator maybe capable of discerning the Avenger from the Devastator due to patchy repair after the battle of Antares.

I understand that RAW an ISD would detect, fire and direct TIEs to any contact at range. That would mean that the player's YT-1300 would be bombarded from nowhere and they would prolly be blast into oblivion before finding the source.

Cheers,