Usually (or very often), good Protoss players, after building a Robotics bay, build observer and put it to opponent base.
From my perspective if you know Protoss build Robo you should care about that observer.
How do I most effectively deny this observer?
The most often I play Terran and there are few ways for that:
- Scan your choke and kill observer with marines. This can fail if observer is not in the scanned screen. That also cost you 50 energy (270 minerals). Observer costs 25/75... if we take gas/mineral exchange rate as 2.5 - it is pretty good price for killing observer...
- Build Engineering Bay and build few turrets. that costs 150+x*75... also not too bad. This will take time, but could be also useful in a long run (detect DT or other observers, some defense against phenixes and VoidRays).
- Build Raven (if you have StarPort with tech lab). That costs 100/200 - a little bit expensive for observer hunting, but you could later use Raven for PDD, etc...
- Anything else?
- What is the best way to hunt observers?
- How to deal with opponent observers if you play Zerg?
- How to deal with opponent observers if you play Protoss?
Thanks a lot!