From Binding of Isaac: Rebirth Wiki
Planetariums are special rooms added in The Binding of Isaac: Repentance containing astronomical items.
Name
ID
Icon
Weight
Description
Jupiter
5.100. 594
1
+2 red Heart containers , -0.3 speed . Isaac builds speed while standing still, and releases poison gas clouds when he moves with increased speed.
Luna
5.100. 589
1
Adds an extra Secret Room and Super Secret Room to each floor. Secret Rooms contain a beam of light that increases tears for the current floor and give soul hearts.
Mars
5.100. 593
1
Dash by double-tapping the movement key, becoming invulnerable and damaging enemies. There's a short cooldown before Isaac can dash again.
Mercurius
5.100. 590
1
+0.4 speed . Doors stay open after entering a room, even in rooms with enemies.
Neptunus
5.100. 597
1
While not firing, Isaac builds a massive tears bonus over 3 seconds. The tear bonus falls off rapidly as Isaac fires.
Pluto
5.100. 598
1
Significantly shrinks Isaac, allowing him to squeeze between objects and makes some enemy shots pass over him. Also gives +0.7 tears.
Saturnus
5.100. 595
1
Upon entering a room, a circle of tears orbits Isaac. Enemy tears have a chance to be caught in orbit, turning them friendly.
Sol
5.100. 588
1
Reveals the location of the Boss room . Upon defeating a boss, activates XIX - The Sun , fully recharges Isaac's active item, and grants bonus damage and luck for the rest of the floor.
Terra
5.100. 592
1
Replaces tears with rocks that deal variable damage, have increased knockback , and can destroy obstacles .
Uranus
5.100. 596
1
Isaac shoots ice tears, which slow enemies and freeze monsters they kill. Frozen enemies slide away and explode into ice shards when touched.
Venus
5.100. 591
1
Adds one red Heart container . Enemies near Isaac become charmed .