Activate astro-viewer in Haven Forest is a mission in Jak 3. Samos Hagai believed the astro-viewer did more than just look at stars, with the Dark Makers having taken over the Southern Haven Forest it would be a fight to even get to the astro-viewer now for Jak.
The PlayStation 3 and Vita versions of this mission are related to a trophy named "Clear Vision", completing this mission will reward you with a bronze trophy.
The objective is to destroy the constant Dark maker reinforcements coming through the odd massive flows on the walls here, they constantly pump out hornets. troopers also spawn every so often, so be once again prepared to use all your best weapons available. You need to take over each of the three Dark Maker turrets spread throughout the forest (they are manned so be careful), this might be difficult due to the firing rate of these massive guns. Using a weapon with a large area of effect or one that does not force you to directly come into their line of fire is useful here, Light Jak's Light Shield is useful too.
Once you have taken over a turret use it to gun down all the flower-things while also maintaining a tab on the many enemies around you. Eventually after destroying them all make a beeline for the pillars in the center, where the next mission starts; "Destroy dark ship shield".