I wanted to confirm that I played properly in a game last night.

It was the start of the Combat Phase, and I had to decide whether I wanted to pop Glitterstim on IG-88B or not. I was very close to range 1 (out of arc) of a Ghost with TLT. If I was at Range 1, popping GS would be a waste because he couldn't shoot at me anyway. If I was at range 2, I'd be eating 2 TLT attacks and GS would have been very helpful to weathering the hail of dice.

However, as I understand it, you can only check range when you are attempting to use a range-limited ability (such as a Target Lock) or performing an attack. Is this correct? My opponent thought you could measure whatever you wanted once we got to the Combat Phase, but I'm not so sure about that.

I opted to forgo checking range. I also decided to use GS, because my best guess was that I was in Range 2. Turns out it was the correct decision, though it was by less than a millimeter. But did I pass up an opportunity to check first?

You played right

Yup. You can only measure range when an effect lets you measure range, and when you activate during the combat phase.

Just to clarify, are you not allowed to check range before picking a target to shoot at?

11 minutes ago, syrilian said:

Just to clarify, are you not allowed to check range before picking a target to shoot at?

You are.

Once you declare that a ship will fire,you can check range for alle potential Target (for that ship) before choosing the Target.

2 hours ago, syrilian said:

Just to clarify, are you not allowed to check range before picking a target to shoot at?

That would be 'when you activate during the combat phase' - and at that point, you can check range and arc to every enemy ship on the board.

Note that once you measure range from one of your attackers - that guy has activated. You can measure to as many enemies as you want, but you CANNOT measure from a different one of your ships, even if they're the same pilot skill. This can presumably matter in cases where you're expecting a ship to kill the other ship. Perhaps Fel was left tokenless at 1 health in range of both of your ships. Ship A has a tokenless Inquisitor at R1 and Fel at clearly R2. Ship B has Inq at R2 and thinks he has Fel at R2, so you activate B first to take the kill shot on Fel but find out that he's actually at R3. Now that you've activated ship B, you must choose to shoot with B onto of them first - do you take the R3 on Fel and hope that between 4 dice and Autothrusters you can do a damage, or do you shoot at the Inq, hoping that ship A can kill off Fel? An amateur might just say "I'm going to shoot with ship A onto Fel at R2" but then a hardcore WAAC player won't allow ship B to shoot since it activated and didn't shoot.

At a tournament generally I'd expect my opponents to activate correctly, in order, and would probably give them a pass the first time, but not thereafter. It matters. The decision of which ship to activate first when they're all the same PS can be the difference between winning and losing (e.g. accidentally killing a Phantom's only target so it can't recloak, or shooting Dengar with the in-arc ship first, then getting Weapons Failure or Blinded Pilot with the out of arc ship.)