Is that all in 1 era? Same for capture 10 relics...

yes its in 1 complete round
u need to get 50 ufos in 1 round

its one of the hardest achivement... I tried to do it, in more then 3 eras... But still undone.

I heard that there is some kind of cheat to get ufos but I don't know how to do it

You must capture all 50 within one era

V-

well, its not much difficult as i know some players having it.

things you should do are,

Play an era Most Probably 1 ticker, (which may give you enough time to do that)

play, actively,

Play, Zooming 100%

keep scrolling map slowly,

Keep an Eagle eye for UFO's...

Thats it......

I put up a cheat for it but cba finding it.

Basically zoom out as far as you can so you can still see everything on the map in detail (so colonies still look like colonies and not yellow blobs). Then pan the map slowly, but quick enough so everything on the map doesn't have time to load (all you will see is the background of the map, if you keep scrolling and don't stop). UFO's don't need a loading time so they will stick out when it's the only visible thing on the map.

I got 50 ufo achievement in around 500 ticks this way on a 2 tick world. Could have been a lot quicker if I'd actually dedicated the era to looking for ufos

viewtopic.php?f=411&t=23677 Found it. This will explain it in a lot more detail with pictures.

I found UFOs by once again zooming out till colony's still look like colony's then go to the top right of the screen and click toggle visibility then you turn everything invisible, then just slowly pan the map till you find them.