The question is, rather: "How can you identify turrets on a ship... without opening the fitting window?"
Now why is this relevant at all? The fitting window is oh-so-convenient! Well, your ship's HUD has a convenient button to send one of your camera drones to look at other ships.
Unfortunately, this only functions when your target is within 100 km of yourself, but that is usually (exceptions for battleships and sniper HACs/battlecruisers) more than enough of a safe buffer to safely examine their ship. Now, when you look at them, you not only see the direction they are flying in, but you also see their guns -- the only visible modules of a ship.
Say you spot this Incursus burning at you:
Most people can't tell. However, I can tell you that those guns are Light Neutron Blaster IIs. How? I've spent a long time observing various guns and their looks. Each caliber/type of gun has a unique profile. Plus, T2 guns generally look like a more shiny/enhanced version of the T1 gun, possibly adding some extra targeting bits, or having more power cables exposed. To spare you the trouble of stalking ships to see all the different turrets, I went and bought every type of small (frigate-sized) turret and fitted them to various ships.
|Click to see the full size table.|
How is this information useful? Well, in this case, by noticing the neutron blasters, a wise pilot will not orbit the Incursus at anywhere closer than 5 km to deny it optimal damage. Alternatively, a ship with a tracking disruptor could load a tracking disruption script, to further break the already poor tracking of neutron blasters. If, on the other hand, those were electron blasters, the safe distance to engage the Incursus becomes much smaller.
This information might not be much, but it can very well make enough of a tactical difference to win you fights. Now go out there and try it!
(No, I cannot and will not make a table like this for cruisers or battleships, since I cannot use those guns)
This is also a fun party trick, especially when bored in space. Tell people exactly what their guns are, and watch them be amazed. Though probably not anymore, if they read my blog.