Astromancy Spells

*Consuming Void

Necromancy cantrip
Casting Time: 1 action
Range: 30 feet
Components: V, S
Duration: Instantaneous
You devour a portion of a creature's potential energy, warding yourself with a sliver of their essence. A target that you can see within range must make a Constitution saving throw or take 1d6 necrotic damage. You then gain temporary hit points equal to the amount of damage dealt until the end of your next turn. Undead and constructs automatically succeed on the saving throw against this effect. This spell’s damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).

Polaris Bolt

Evocation cantrip
Casting Time: 1 action
Range: 60 feet
Components: V, S,
Duration: 1 round
You hurl a twinkling bolt of starlight at a creature you can see within range. The target must make a Dexterity saving throw. On a failed saving throw it takes 1d6 radiant damage and its AC is reduced by 1d4 until the end of your next turn. This spell’s damage increases by 1d6 when you reach certain levels: 5th level (2d6), 11th level (3d6), and 17th level (4d6).

Watchful Eye of Sirius

1st-level enchantment
Casting Time: 1 action
Range: 30 feet
Components: V, S, M (a cat’s eye gemstone)
Duration: 1 hour
Up to three willing creatures within range are enveloped in starlight. They become a beacon of dim light in a 5-foot radius. While they emit this light, the first time each turn that they are struck by a melee attack made within 5 feet of them, the attacking creature takes 1d4 radiant damage. An affected creature can add 1d4 to an attack roll or saving throw they make during the duration. If they do, the spell ends for them.
At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the damage dealt increases by 1d4 for every 2 spell slot levels above 1st.

*Relativity

1st-level enchantment
Casting Time: 1 bonus action
Range: 60 feet
Components: V, S, M (a rabbit's foot and a turtle's shell)
Duration: Concentration, up to 1 minute
You subtly hasten and slow the ambient energy surrounding nearby creatures. A target of your choice within range must make a Wisdom saving throw or have its movement speed reduced by 10 feet for the duration of the spell. If a target fails this saving throw, you can also select a creature within range and increase its movement speed by 10 feet until the spell ends. This effect may not reduce a target's movement speed below 0 nor give movement to a creature beyond the amount of reduced speed. Targets with no movement speed automatically succeed the saving throw.
At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, you can slow and hasten creatures by an additional 10 feet for each slot level above 1st.

Space Twist

1st-level evocation
Casting Time: 1 action
Range: 60 feet
Components: V, S
Duration: Instantaneous
You create a small shimmering distortion in a point within range that you can see, disturbing the course of movement for any creature within 10 feet of it. Creatures within 10 feet of that point must succeed on a Dexterity saving throw or be dealt 2d8 radiant damage and walk the first 10 feet feet of its movement during its next turn in a random direction determined by a d8. If the direction rolled is blocked, the target loses 10 feet of its movement for that turn. The target gains no benefit from cover for this saving throw.
At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d8 for each slot level above 1st.

Stardust Re-Spark

3rd-level abjuration
Casting Time: 1 reaction
Range: 40 feet
Components: V, S, M (a handful of powdered phosphorus)
Duration: Instantaneous
When an ally within range of you drops to 0 hit points and falls unconscious, you can use your reaction to cover them in twinkling light. Any attack against them that would cause them to lose 2 death saving throws causes them to lose only 1. If they are not dead, they become stabilized and at the start of their next turn they come to consciousness with 1 hitpoint.

Lysander’s Aether Burst

3rd-level evocation
Casting Time: 1 action
Range:150 feet
Components: S, M (a vial of stardust)
Duration: Instantaneous
A burst of pulsating light particles and swirling starlight flashes in a 15 foot radius sphere centered on a point within range. Creatures in the area must make a Constitution saving throw or suffer 3d6 radiant and 3d6 force damage and be blinded until the end of their next turn. On a successful save, the damage is halved and the creature is not blinded.
At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 per damage type for every two slot levels above 3rd.

Aurora Borealis

3rd-level enchantment
Casting Time: 1 action
Range: 60 feet
Components: V, S, M (a crystal vial filled with stardust)
Duration: Concentration, up to 1 minute
You create a twisting pattern of colorful polar lights that weaves through the air inside a 30-foot cube within range. Any creature in the aurora’s area must succeed a Dexterity saving throw or be wreathed in scintillating light. For the duration, objects and affected creatures shed dim light in a 10-foot radius. Any attack roll against an affected creature or object has advantage if the attacker can see it and attack rolls against an affected creature deal an additional 2d6 radiant damage. An affected creature or object can't benefit from being invisible.

Pulsar

4th-level evocation
Casting Time: 1 action
Range: 120 feet
Components: V, S
Duration: Concentration, up to 1 minute
A luminous, magnetized star forms in a 20-foot radius sphere centered on a point you can see within range. Each creature in the sphere when it appears or that starts its turn there takes 1d12 bludgeoning damage as they are crushed by the stars intense gravity. The sphere's space is difficult terrain. When you cast this spell, and as a bonus action on each of your turns until the spell ends, you can cause the star to emit a beam of magnetized radiation from the center of the sphere toward one creature you choose within 60 feet of the center. Make a ranged spell attack. You have advantage on the attack roll if the target is in the sphere. On a hit, the target takes force damage equal to 2d12 plus your spellcasting ability modifier. On a hit, the creature must make a Constitution saving throw or suffer one level of exhaustion and emits a dim, silver light in a 5-foot radius. This light makes it impossible for the creature to benefit from being invisible. The light and any levels of exhaustion caused by this spell go away when the spell ends.

Born from Draconis

5th-level abjuration (ritual)
Casting Time: 1 hour
Range: Touch
Components: V, S, M (a pouch containing a lock of your own hair wrapped around a diamond worth 150 gold)
Duration: 8 hours
When you finish a long rest, you touch a willing creature and share the strength of the heavenly bodies with them. Choose one of the following abilities to impart to the creature:
Sun’s Warmth. The creature gains resistance to fire damage and is immune to the blinded condition.
Moon’s Grace. The creature gains resistance to cold damage and is immune to the charmed condition.
Star’s Radiance. The creature gains resistance to radiant or necrotic damage (your choice) and is immune to the frightened condition.
Planetary Might. The creature gains resistance to bludgeoning damage and cannot be knocked prone.
A creature cannot benefit from more than one of these resistances at the same time.

*Wall of Dusk

5th-level illusion
Casting Time: 1 action
Range: 120 feet
Components: V, S, M (a small bottle of ash)
Duration: Concentration, up to 10 minutes
A wall of shadowy gloom appears at a point you choose within range. The wall appears in any orientation you select: horizontally, vertically, or diagonally. It can be free floating, or it can rest on a solid surface. The wall can be up to 60 feet long, 10 feet high, and 5 feet thick. The tenebrous wisps that constitute the wall block line of sight, but creatures and objects can pass through it.
Creatures of your choice that pass through the wall become invisible until the spell ends, as twilight clings to them. Anything the target is wearing or carrying is invisible as long as it is on the target’s person. This invisibility ends for a target that attacks or casts a spell.
Each time a creature gains invisibility from this effect, the wall’s length is reduced by 10 feet. If the wall’s length is reduced to 0 feet in this way, creatures that are invisible due to its effects remain so while you maintain concentration on this spell.
At Higher Levels: When you cast this spell using a spell slot of 6th level or higher, you can increase the length of the wall by 10 feet for each slot level above 5th.

*Magnetic Ward

5th-level abjuration
Casting Time: 1 action
Range: Self
Components: V, S
Duration: Concentration, up to 1 minute
You create a 20-foot radius sphere of repulsing magical energy centered on yourself for the duration. This area is an electromagnetic bubble and only affects objects you select. Creatures of your choice that possess or are wearing metallic objects, such as a metal weapon or armor that come into contact with the sphere’s boundary must make a Strength saving throw or take 4d8 lightning damage and are unable to cross the border. Creatures that succeed take half damage and may move through it. Metal projectiles cannot pass the sphere’s boundary and are deflected away. When a ranged attack is deflected in this way, you can use your reaction to fire a charged projectile back towards the creature that shot it, forcing the creature to make a Dexterity saving throw or take 4d8 lightning damage, or half as much on a successful save.
At Higher Levels: When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d8 for each slot level above 5th.

Event Horizon

5th-level evocation
Casting Time: 1 action
Range: 100 feet
Components: V, S, M (A bar of lead and a dark pearl)
Duration: Instantaneous
You concentrate gravity in a powerful field that is a 30-foot cube. Each creature in that area must make a Strength saving throw. On a failed saving throw, a creature takes 5d10 force damage and is knocked prone. On a successful save, the creature takes half as much damage and isn't knocked prone. Flying creatures in the area make their saving throws with disadvantage and and take an additional 1d6 bludgeoning damage for every 10 feet they fall.
At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the dimensions of the cube increase by 10 feet for every slot above 5th.

Conjunction

6th-level evocation
Casting Time: 1 action
Range: 100 feet
Components: V, S,
Duration: Concentration, up to 1 minute
You fill a 30-foot-radius sphere centered on a point within range with intense gravity which is difficult terrain. Creatures of your choice in that area must make a Strength saving throw. On a failed saving throw, a creature takes 10d6 force damage and is pulled in a straight line toward the center of the sphere, ending in an unoccupied space as close to the center as possible where it is restrained (even if that space is in the air). On a successful save, the creature takes half as much damage and isn't pulled or restrained. A restrained creature can repeat the save at the end of each of its turns, ending the effect on itself on a success. As a bonus action on following turns, you can deal 2d6 force damage to creatures restrained within the sphere.
At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, the initial damage and the bonus action damage increases by 1d6 for every slot above 6th.

Astral Transformation

7th-level transmutation
Casting Time: 1 bonus action
Range: Self (60-foot cone)
Components: V, S, M (an astronomy tool worth at least 500 gp)
Duration: Concentration, up to 1 minute
Imbuing yourself with the power of the cosmos, you are transformed into a starry avatar of their power. You shed bright light in a 10-foot radius and dim light for another 10-feet. You gain the following benefits until the spell ends:

Parallax. When you would be struck by an attack you can see, you can roll a d6 (no action required). On a roll of 5 or 6, the attack misses and you can choose to be displaced 5 feet to an unoccupied space (this does not provoke opportunity attacks).

Cosmic Flare. When you cast this spell, and as a bonus action on subsequent turns for the duration, you can expel a torrent of starfire and light in a 60-foot cone. Each creature in that area must make a Dexterity saving throw, taking 6d8 force damage on a failed save, or half as much damage on a successful one.

Flight. You gain a flying speed of 60 feet.

Lysander’s Astral Cannon

7th-level evocation
Casting Time: 1 action
Range: Self (60-foot line)
Components: V, S, M (a crystal vial filled with stardust)
Duration: Instantaneous
You extend your hand outward in a clenched fist as stars and glowing rings surround you. A beam of celestial energy blasts out from you in a 60-foot line that is 10-feet wide. Each creature in the line must make a Dexterity saving throw. A creature takes 5d8 force damage and 5d8 radiant damage on a failed save, or half as much damage on a successful one. The AC of a creature that fails this save is reduced by 1d4+1 until they take a short or long rest as starlight clings to them.
At Higher Levels: When you cast this spell using a spell slot of 8th level or higher, the damage increases by 1d8 for each damage type for every two spell slots used above 7th.

Laxius' Eclipsing Jaunt

7th-level conjuration
Casting Time: 1 action
Range: 10 feet
Components: V
Duration: Instantaneous
You and up to five other creatures or objects teleport as per the Teleport spell. However, your arrival in your new location causes the area within 10 miles of you to become night even if it is daytime. This night lasts for 24 hours, or until you cancel it as an action.

Aether Storm

8th-level evocation
Casting Time: 1 action
Range: 150 feet
Components: V, S
Duration: Instantaneous

You tear a portal through the dimensional veil between your location and the Astral Plane, allowing a portion of an astral storm to spill into the material plane in a torrent of star fire, silvery gossamer, and shimmering auroras in a location you choose within range. The area of the storm consists of up to seven 10-foot cubes, which you can arrange as you wish. Each cube must have at least one face adjacent to the face of another cube. Each creature in the area must make a Dexterity saving throw. It takes 12d6 force damage on a failed save, or half as much damage on a successful one.

The storm clouds linger until the end of your next turn when they dissipate leaving no trace. Until then, the clouds fill the spaces they appeared in and lightly obscure those areas. When a creature starts their turn in this area, they must make a Wisdom saving throw or it can't take reactions until the end of their next turn. A creature that fails this saving throw must also roll a d10 to determine how the storm affects them as shown on the Aether Storm Effects table.

d10	Aether Storm Effects
1-2	Enchanting Borealis. The creature is stunned until the end of the turn.
3-5	Visions of Madness. The creature uses its action to make an attack against a randomly determined creature within its reach. If there is no creature within its reach, the creature does nothing this turn.
6-8	Hurl Though Space. The creature is teleported, along with everything it is wearing and carrying, up to 30 feet to an unoccupied space of your choice that you can see. The target lands prone on the ground.
9-10	Nebula Burst. The creature suffers 4d6 psychic damage from the storms after current.

Brightness of the Fifth Star

8th-level evocation
Casting Time: 1 action
Range: Self (40-foot radius)
Components: V, S
Duration: Concentration, up to 1 minute
You call upon Vega, the brightest star in the constellation of the Harp, to flare in the sky above you, eclipsing all other light. Its power surrounds you even where the sky can’t be seen, and even on other planes. You manifest an area of bright silver-blue light in a 40-foot radius around you. The light dispels any darkness in its area that was created by a spell. When you create this area, you can choose any number of creatures within it. While they are in the area, they make saving throws with advantage and cannot be charmed or frightened.
Additionally, hostile creatures that enter the area for the first time on a turn or start its turn there must make a Constitution saving throw. The creature takes 8d10 radiant damage on a failed save, or half as much damage on a successful one. A creature reduced to 0 hit points by this damage is disintegrated. A disintegrated creature and everything it is wearing and carrying, except magic items, are reduced to a pile of fine gray dust.

Collapsing Star

8th-level evocation
Casting Time: 1 action
Range: 300 feet
Components: V, S, M
Duration: Instantaneous
You create a 20-foot radius sphere of crushing void and celestial light centered on a point you can see within range. Creatures within the sphere must make a Constitution saving throw or suffer 5d10 cold damage and 5d10 force damage, halved on a save. A creature not reduced to 0 hit points by this damage must then make a Wisdom saving throw or be teleported 1d100 miles away in a random direction. If the creature is not on its home plane, it is returned to a random location on its home plane.

*The Celestial Void

9th-level evocation
Casting Time: 1 action
Range: 1000-feet
Components: V, S
Duration: Concentration, up to 1 minute
You tear open a gateway to the crushing expanse of space, creating a microcosm of blinding magical starlight in a 20-foot-radius sphere centered on a point you can see within range. No sound can be created within or pass through the sphere's area. Any creature or object entirely inside the sphere is immune to thunder damage, and creatures are deafened, blinded, and cannot be seen from outside the sphere while entirely inside it. Casting a spell that includes a verbal component is impossible within its area. The sphere emits bright light in a 50-foot radius and dim light for another 50-feet. For the spell's duration, the sphere and any space within 100 feet of it are difficult terrain, and nonmagical objects fully inside the sphere are destroyed if they aren't being worn or carried.
When the sphere appears and at the start of each of your turns until the spell ends, unsecured objects within 100 feet of the sphere are pulled toward the sphere's center, ending in an unoccupied space as close to the center as possible.
A creature that starts its turn within 100 feet of the sphere must succeed on a Strength saving throw or be pulled straight toward the sphere's center, ending in an unoccupied space as close to the center as possible. A creature that enters the sphere for the first time on a turn or starts its turn there takes 5d10 force damage and is restrained until it is no longer in the sphere. If the sphere is in the air, the restrained creature hovers inside the sphere. A creature can use its action to make a Strength check against your spell save DC, ending this restrained condition on itself or another creature in the sphere that it can reach. A creature reduced to 0 hit points by this spell is annihilated, along with any nonmagical items it is wearing or carrying.

Credit

Spells marked with an asterisk (*) are not spells of my creation. They were taken from one of the below sources, or are official pre-existing spells that I've simply renamed for flavor.
https://www.dndbeyond.com/subclasses/97455-chronomancer
https://www.dmsguild.com/product/234311/Stargazer-Class-DD-5e https://drive.google.com/file/d/1FO2-ci0Fsa8VIdOy8ba000Flt3sDexBX/view
https://homebrewery.naturalcrit.com/share/Hk1pqInWm
https://www.reddit.com/r/UnearthedArcana/comments/fqvv75/the_revised_astromancer_class_for_5e_v3_includes/
https://www.gmbinder.com/share/-M3CbZu0R4G7CbVcmMqN