Re: Different Scanners
 

In stock (i.e. no mods), yes.

Re: Different Scanners
 

In other words, never bother with Tachyon Sensors. Gravitic Sensors are too expensive too if memory serves, as you will want to do some research in the Hyper Optic tech anyway (it gives you training, and that may be one of the most important things for your warships).

Re: Different Scanners
 

It's kinda what I thought. I just hope that SEV has a little better explanation of all the systems then SEIV has. It probably should be noted somewhere that all these systems perform the same actions toward seeing hidden (cloaked) ships. The way it reads now is that Tachyon sensors are the only ones that can see cloaked ships. Tachyon sensors are the expensive ones.

Re: Long Range Scanners
 

Another use I was just reminded of it the ability of these scanners to see what space based shipyard are building and the time to completion.

Assuming you have some knowlege of ship types and build times, this information can be used to help plan attacks. Capture ships can choose a sector with the turns remaining at two, while saving sectors with turns remaining of 6 till later. You can see if a remote mining base is being built, or warships for the mill.

While not close to the top of the research tree, they can be useful, and I would not put them at the bottom.