n medium human humanoid 

Perception +10

Languages Common

Skills Arcana +8, Astronomy Lore +12, Occultism +8

Str +0 Dex +1 Con +2 Int +4 Wis +3 Cha +0

Items astrolabe, spellbook, spell component pouch, staff

Living Sextant If the astronomer is able to see the night sky, they can Sense Direction using a +10 modifier.

AC  15; Fort +6, Ref +5, Will +9

HP 23

Counterspell [R] Trigger A creature Casts a Spell the astronomer has prepared; Effect The astronomer expends a prepared spell to counter the triggering creature's casting of that same spell. The astronomer loses its spell slot as if it had cast the triggering spell. The astronomer then attempts to counteract the triggering spell.

Speed 25 feet

Melee [>] staff +6 (two-hand d8), Damage 1d4 bludgeoning

Gamemastery Guide, page 241.