You don't need to have a covops or a cloak or check every moon in a pod to find hostile POSes. all you need is a regular ol' frigate or any ship that can preferably zoom along at a decent clip. HERE'S HOW!!
Choose a planet to scan. POSes are put up at moons, so don't be a retard and warp to a planet without any moons.
Set up your overview to scan for POSes. The initial scan only needs two things: Control Towers and Moons. Unselect all items in your overview settings and then select Control Towers from the Structure menu and Moons from the Celestial Object menu. Save the setting as POS Scan or something.
Begin warping to the planet you'll be scanning at your choice of range, open up the add bookmark dialog and click OK once your warp starts slowing down and the distance from destination at the bottom of the screen is within a few hundred thousand KM. Warp back to your new scanspot once you arrive, where you can sit and scan safely without worrying about people warping in to the planet and seeing you.
Make sure your overview is set to your new POS Scan setting. Either sort your overview by range or hold the "alt" key to make moons show up on your screen and check the range of each moon around the planet. Set your scan range a bit beyond the farthest moon, as moon warpins are usually ~5,000 km out from the moon. For example, if the farthest moon is 0.2 Au away, set your scan range for 0.3 Au (1 Au = 150 million km, 0.3 Au = 150,000,000 x 0.3 = 45,000,000 km). Do a 360 degree scan, making sure that you have the "Use Overview Settings" box checked.
You should now have a scan of all the POSes at the planet. Narrow your scan range down to about 60 degrees, and use the "alt" key to find the moons in space. Scan each moon, and try to find which moons have POSes. Its very easy to see on your scanner because you have moons on overview, and the POSes should show up along with the moon. If you get several moons and a POS, narrow your range down more and continue scanning to find the moon.
Alternatively, if you have moons on your overview, then you can scan incrementally at each distance at 360 if you know that there's a POS at that planet. For example:
Planet 5 has one POS and three moons:
- Moon 1: 145,362km
- Moon 2: 285,629km
- Moon 3: 426,198km
Scan at 150,000 km 290,000km and 430,000km and you'll find it. I find this easier than the point-and-shoot method of looking at each moon at 60 degrees.
Now you know which moons have POSes, and you know what kind of POSes they are. you still need to know what kind of setups you're looking at, though - are we going to attack a minmatar death star, or just a piddly little research/refinery? No problem, you don't even need to move. Go back to your overview settings, and check everything under the Structures menu. Save the setting as something like "POS Composition". Narrow your scan range down, and using the "alt" key to find moons, point your scanner at one of the POS moons. Hey presto! you now know exactly what you'll be dealing with when the dreads cyno in, and best of all you don't even need to risk your ship or find a covops to do it!
See also: Scouting Intro