Can't get into Varkid Ranch Observatory building

[zaphod]

Went all around, climbed ladder to platform. The only thing I could do from the outside was to shoot the fuse box which had no discernible effect. Been studying it for at least an hour but I must be stupid, blind or both.

[I-Chi]

IIRC there's a tunnel underneath the facility. It's usually blocked by an electric field which should be switched off by shooting the fuse box.

[Bunkyguy]

OK...you did try to disable the electric field using what? Sometimes depends the type of ammo you are using. Try using explosive ammo,which works the best or regular ammo.
If you still have problems, go to You Tube and watch the video how to disable the electric barrier.

[lena]

When you go on the roof, there's a fuse box. Shoot that fuse box. Then, continue to the bottom of the tower, through a tunnel which is usually blocked off by an electric fence, disabled by the fuse box y'shot. Yeah? Ok. Then you can enter. Oh, and a small tip; You can get the XP for discovering the Varkid Ranch Observatory by standing against the door.