The Astral Calculus
A meticulous wizard’s star-chart codex holds the key to a vanished observatory and the dangerous spellwork sealed beneath it.
Spellbook · Wizard, School of Evocation · Level 5
The Astral Calculus
A meticulous wizard’s star-chart codex holds the key to a vanished observatory and the dangerous spellwork sealed beneath it.
Ex librisVesper ArclightArcane wizard
At a glance
Level
5
Wizard, School of Evocation
Spells
10
1 cantrip, 2 signature
At the table
A margin note
Plot hook
Spells
10 spellsCantrips
1- A frigid ray deals cold damage on a hit and reduces the target’s speed by 10 feet until the start of your next turn.
- Duration
- Instantaneous
- Target
- One creature
- Components
- V, S
- Save or attack
- Ranged spell attack
- Damage
- cold
- Higher levels
- Damage increases to at character level 5.
- Source
- System Reference Document 5.1
1st level
4- A willing creature not wearing armor has a base AC of 13 + its Dexterity modifier for the duration.
- Duration
- 1 hour
- Target
- One willing creature not wearing armor
- Components
- V, S
- Higher levels
- No additional effect when cast with a higher-level slot.
- Source
- System Reference Document 5.1
- You create three glowing darts of magical force that automatically hit their chosen targets.
- Duration
- Instantaneous
- Target
- One or more creatures you can see
- Components
- V, S
- Save or attack
- None; each dart hits a creature of your choice that you can see
- Damage
- 3 darts, each dealing force
- Higher levels
- One additional dart for each slot level above 1st.
- Source
- System Reference Document 5.1
- You sense magic within 30 feet and can use an action to see a faint aura around a visible magical creature or object and learn its school, if any.
- Duration
- Concentration, up to 1 minute
- Target
- Self; magical effects within 30 feet
- Components
- V, S, M (a tiny strip of white cloth)
- Higher levels
- No additional effect when cast with a higher-level slot.
- Source
- System Reference Document 5.1
- Create a visual illusion of an object, creature, or phenomenon that fits within a 15-foot cube; you can move it and alter its appearance within the spell’s limits.
- Duration
- Concentration, up to 1 hour
- Target
- A point within range
- Components
- V, S, M (a small piece of fleece)
- Save or attack
- Investigation check against your spell save DC to discern the illusion
- Higher levels
- The image’s maximum dimensions increase by 10 feet for each slot level above 1st.
- Source
- System Reference Document 5.1
2nd level
3- Create three rays of fire and make a separate ranged spell attack for each; each hit deals fire damage.
- Duration
- Instantaneous
- Target
- One or more creatures within range
- Components
- V, S, M (a bit of fleece)
- Save or attack
- Ranged spell attack for each ray
- Damage
- force per missile
- Higher levels
- One additional ray for each slot level above 2nd.
- Source
- System Reference Document 5.1
- Create a 20-foot cube of sticky webs that is difficult terrain and lightly obscures its area. Creatures can become restrained; the webs are flammable.
- Duration
- Concentration, up to 1 minute
- Target
- A point within range
- Components
- V, S, M (a pinch of dust, a few drops of water, and a tiny silver loop)
- Save or attack
- Dexterity saving throw when a creature enters the webs or starts its turn there
- Higher levels
- The webs spread to an additional 5-foot cube for each slot level above 2nd.
- Source
- System Reference Document 5.1
- A sudden, painfully loud ringing sound erupts from a point you choose. Creatures in a 10-foot-radius sphere take thunder damage.
- Duration
- Instantaneous
- Target
- Creatures in a 10-foot-radius sphere centered on a point within range
- Components
- V, S, M (a pinch of soot and saltpeter)
- Save or attack
- Constitution saving throw; half damage on a success
- Damage
- thunder
- Higher levels
- Damage increases by for each slot level above 2nd.
- Source
- System Reference Document 5.1
3rd level
2- A bright streak erupts into a 20-foot-radius sphere of flame. Creatures in the area take fire damage.
- Duration
- Instantaneous
- Target
- A point within range
- Components
- V, S, M (a tiny ball of bat guano and sulfur)
- Save or attack
- Dexterity saving throw; half damage on a success
- Damage
- fire
- Higher levels
- Damage increases by for each slot level above 3rd.
- Source
- System Reference Document 5.1
- You attempt to interrupt a creature in the process of casting a spell. On success, that spell fails and has no effect.
- Duration
- Instantaneous
- Target
- A creature casting a spell within range
- Components
- S
- Save or attack
- Automatically interrupts a spell of 3rd level or lower; for a higher-level spell, make an ability check using your spellcasting ability, + the spell's level
- Higher levels
- Automatically interrupts a spell whose level is equal to or lower than the slot used.
- Source
- System Reference Document 5.1
In the margins
4 notes
WarningDo not cast Fireball beneath a low wooden ceiling. Again.
DiaryThe third star in the eastern chain moves when the book is lied to.
FormulaFor the counterspell lattice, reverse the final two strokes only if the hostile working is already formed.
DiagramA rough diagram shows a hand-shaped constellation linked to a silver-ringed eye.
The book itself
The pages are arranged by celestial season rather than spell level.
Silver ink on the diagrams catches the light like distant stars.
The caster
Arcane wizardVesper Arclight
Studies: Evocation, with a strong interest in divination and magical theoryManner: Precise, courteous, and faintly distracted, as if listening for a distant signal.Focus: A brass astrolabe with a cracked lens, used to trace spell patterns in the air.Quirk: Counts prime numbers under her breath whenever a spell goes awry.Wants: To find the vanished observatory’s buried annex and learn what the old star charts were designed to track.Vesper Arclight was an observatory apprentice until a misread celestial conjunction collapsed the tower’s upper library. She salvaged this codex and has spent years reconstructing its scattered formulae.
The book
A compact, midnight-blue codex bound in cracked leather, its silver corner plates etched with constellations. Fine copper wire stitches the spine, and the pages shimmer faintly when opened beneath starlight.
Its wards · GM only
About the book
FormatStar-chart codex
ThemeArcane
Written by aWizard, School of Evocation
Caster level5
SystemGeneric Fantasy
Plot hooks
1A star map hidden beneath the codex’s endpaper points to an abandoned observatory whose central telescope is still tracking something underground.
2The silver ink begins rearranging itself, revealing a constellation that was absent from every known chart.
3A rival scholar claims the codex was stolen from her family archive and demands its return before the next new moon.
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