Sensor rules part 2

What is this Marre-red maneuver Sir?

It was invented by a rather colourful pirate called Mauricius Redondo way back and is used when you come out of the sun and assume your enemy is hiding in the planetary shadow. You approach the planet building up quite some speed, say 30 to 50 klicks a second, and drift as you pass above or below the planet with your powerplant off. Keep drifting ’til you think you passed the enemy the power up the reactor and start braking. You are now ‘south’ of your opponent, in the planet shadow with your enemy to sun-ward yet no risk of any sun-blinding. Then you take him out son.

Sensors part 1 skipped the rules on how planets and asteroids may affect scans, this post is going to remedy that, first with the actual rules and then some examples on how this work in practice. The following blog posts deal with the the different sensor types and how to avoid being detected by them.

Planet Line Of Sight (LOS)

Planets block line of sight, it’s quite obvious; just look down at the ground at night and notice that you cannot see any stars.

Ships far from a planet cannot see targets on the opposite side of the planet if they are near the planet. Ships near a planet cannot see targets on the opposite side of the planet, regardless of how far they are, and ships scanning for targets near a planet cannot see targets if they are opposite the planet regardless of how far away they are.

Planets and asteroid columns

Shadow column

Planets cast long shadows where ships can hide. The column below a planet, 1 square wide for Small planets, 3 squares wide for Large planets, is called the Shadow column. Ships and missiles in the Shadow column treat the Sunfactor as 0 instead of its normal value (usually 6), no other signatures are affected by planetary shadows. Ships in shadow also ignore Sunglare.

Planet LOS sectors

Planets also block Line Of Sight (LOS) of course, ships on one side of the planet won’t see and won’t be seen by ships on the other side. Planets have sectors that delineate who can see whom, near sectors that are simply the 8 arcs of the gravity well, and far sectors that extend the gravity arc all the way out to the edge of the map. If your ship is inside a gravity well the opposite near & far sector are blocked. If your ship is outside of the gravity well but your scan touches the gravity well the opposite near sector is blocked. Planet LOS is symmetric so a ship cannot see a someone that cannot also seem them. Look at the pictures for the near and far sectors of planets, small and large.

So, how does this work in practice? The scanner has placed a Scan somewhere and it’s up to the target, to make sure it is a legit Scan. This is done by the target asking the scanner a few simple questions and act upon the answers.

Does the Scan touch your ships Sunglare?

  • Ships in shadow ignore Sunglare

If the scan touches your Sunglare column and you are not in shadow you say yes and reduce the scan strength of your scan by Sunfactor (typically 6). If the scan does not touch your Sunglare column or your ship is in shadow you answer no and leave the scan as it was. This question is always asked.

Does a planet block parts of your Scan?

  • If scanner and scan is outside of gravity ignore Planet LOS
  • Near sector block opposite near and far sectors
  • Far sector block opposite near sector only

Your opponent now asks you if the planet blocks part of your scan.

If your ship is inside the gravity well (a near sector) the opposite near and far sectors are blocked. If your scan touches any of the blocked sectors you must tell your opponent what is blocked of the scan, if your scan doesn’t touch the blocked sectors you tell him nothing.

If your ship is in a far sector the opposite near sector only is blocked. If your scan touches that blocked sector you must tell your opponent what is blocked, if your scan doesn’t touch the sector you tell him nothing.

Planetary LOS examples

The scanner simply places his Scan somewhere calculates its strength based on Sensor + Scan modifiers. The target of the Scan then ask a series of questions which may lower the Scan or make certain parts of it ignored. Scans are done in reverse Initiative order.

Scan 1

A has his ship located in 1 and decides to do a 1 box Scan in box B4. His Sensor is +2 and the scan modifier for a 1 box scan is -1.
Player A ”I have a visual scan, strength +1, one box large, in box B4.”
Player B ”Does your Scan touch your ships Sunglare column?”
Player A ”Yes, my Scan touches my Sunglare, dammit!”
Player B ”Is your scan from or does it touch a gravity well?”
Player A ”No, it’s not from gravity and you can see it doesn’t touch it”
The scanner grudgingly admits that the Scan does touch his Sunglare column so the target reduce his Scan strength by -6 to an abysmal -5. If the target was not inside the Scan he would say Nothing, if inside the Scan but with a Signal of -1 the target would still say Nothing, if the Signal was 0+ it would be a Contact so the target would tell its position and what Signature(s) that gave 0+ Signal, the scanner would then probably do a Sense task to try to get a Tracked result on the target. The target player has also learned that the scanner’s ship is somewhere below the Scan, thank’s to the Sunglare.


I have colored the entire Scan 1 orange because of the Sunglare strength reduction, the Scan is still valid but very weak. Don’t stare into the sun.

Scan 2

Player A has moved his ship into position 2 and decide to do a huge 3×3 box scan centered around E1. The scan modifier for a 3×3 scan is -3 so his with his +2 Sensor the Scan strength is -1.
Player A ”I have a Visual Scan strength -1 three by three boxes in box E1.”
Player B ”Does your Scan touch your ships Sunglare column?”
Player A ”No it doesn’t. I have learned my lesson”
Player B ”Is your scan from or does it touch a gravity well?”
Player A ”Eh, yes it is”
Player B ”OK does the planet block any of your scan, what sectors if so?”
Player A ”The northeast near and far sector”
The northeast near and far sector is colored gray in the pictures. If player B had any ships or missiles inside the parts of the scan inside northeast near and far those targets would have been ignored. The near is simply the gravity sector and far extends from that forever. The Scan touches the Sun column but as player A wasn’t scanning from the Shadow column this had no effect.

I have colored the parts of the scan that should be ignored in red.

Scan 3

Player A has drifted into position 3 with the help of gravity. He decides to do a 3×3 box Scan in E4. He figures the Shadow column will protects him from Sunglare. The Scan strength is -1.
Player A ”Visual Scan strength -1 three by three boxes in E4.”
Player B ”Does your Scan touch your ships Sunglare column?”
Player A ”No”
Player B ”Is your scan from or does it touch a gravity well?”
Player A ”Not from within, but it touches”
Player B ”OK does the planet block any of your scan, what near sector if so?”
Player A ”Near north”
The scan touches the Sunglare column but as the ship is in shadows the answer is no. The near north sector will be ignored but most of the Scan is still valid as you can see. Had his scanning ship been 3 squares to the right none of the Scan would be blocked,had the ship been one square further up it would be in the near sector (gravity well) so the entire opposite arc would be blocked, all the way to the top of the map.

I have colored the parts of the scan that should be ignored in red.

What about asteroids?

Asteroids cast shadows so you can reduce your Visual(Hull) by staying in their shadows and by staying in their shadows you may also ignore Sunglare. Asteroids are too small to offer Planet LOS blocking however but there is still a way to get LOS blocking from an asteroid; land on them. See page 26 in the rulebook.

What about shadowing?

There is this obscure trick where a ship with the same position, vector and facing of a larger ship lies in its shadow so it treats the Sunfactor as 0. This is called shadowing and and can be done with friendly ships as well as enemies. Sunglare does still apply when being in shadows this way however. Shadowing enemy vessels is a good way to stay undetected as ships rarely scan their own position.

Be cool and stay in the shadows until next time, over and out.

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