Book 2 - The Celestial Almanac

The Astromundi Cluster’s secrets await your perusal between the covers of this volume.

Where The Astrogator’s Guide provided a vital overview of Clusterspace for use by players, this book contains detailed information intended for the DUNGEON MASTER’ only.


Chapter One describes the physical makeup of the Cluster. Here you’ll find information concerning:

Chapter Two deals with the economic aspects of a campaign based in the Shattered Sphere. Each of the major powers has its own methods of trade and piracy, and these are explained. In this chapter you’ll find information that details trade routes and the various exportable commodities found in or around the important settlements in the Cluster.

Chapter Three, the main portion of this book, covers the various ports, cities, and mysterious asteroids that make up the Cluster. This chapter includes a variety of NPCs who figure prominently in the Cluster and may find their way into a campaign.

Chapter Four contains information about sun-magic, including new spells and two Sun Mage magic items; a description of a crystal citadel; and a couple of tanar’ri MONSTROUS COMPENDIUM’ sheets for your use should the Arcane prove successful in their plot.

The Crystal Sphere

The crystal sphere that houses Clusterspace is a very strange one. The sphere is resistant to any spells that could be used to open portals from within, but its interior wall can be breached simply by touching it with a living spelljamming craft, such as those used by the elves. These living ships may pass through the sphere’s inner surface with no difficulty, but no other ship can, even if towed by a living ship.

Note that there is no other way to breach the interior of the crystal sphere.

With the ability to leave the Cluster at will, the elves have gained power disproportionate to their numbers. Other races must bow to the demands of the elves if they want to journey beyond the sphere, and the elves have used this advantage mercilessly. The elves have also kept the secret of why they can leave the crystal sphere, knowing that their power will end as soon as someone else discovers that the living ships are the key.

From the outside, the Cluster’s crystal sphere is as easy to pass through as a wall of mist. Ships approaching the crystal sphere will pass through quickly and with no difficulty — only to find they cannot escape.

Wizshades (SPELLJAMMER® MC 7) are behind the selective egress” aspect of the crystal sphere. There are several such creatures within the Astromundi Cluster, and they are intimately tied to the sphere itself (see The Sundeath chapter in Adventures in the Shattered Sphere for more information). The wizshades knew of the tanar’ri plot to conquer the Cluster and invested the sphere with a portion of their sentience. This allows the sphere to screen those beings who wish to leave the Cluster, thereby preventing a tanar’ri conquest of the Prime Material Plane.

Other Planes

The Astromundi Cluster resides within a crystal sphere that has a unique relationship with the other planes of existence. While most crystal spheres are firmly rooted in the Prime Material Plane, Clusterspace bobs within a boundary region where the barriers between the various planes are quite weak. Thus, it is possible for creatures to pass through the Inner Planes with relative ease in and around the Astromundi Cluster. This has allowed a number of evil creatures to come into the Cluster from other planes, but also allows the entrance of good creatures who may serve as allies to the characters.


For purposes of game mechanics, the following rules apply to characters or creatures interacting with the various planes of existence.

First, characters traveling in the phlogiston within 1,000 miles of the crystal sphere can travel to the Ethereal Plane by concentrating on their desire to do so for no less than two turns. Of course, not many people are going to be moving through the phlogiston and suddenly decide they want be in the Ethereal Plane! The elves know this secret, but, as with all elven secrets, they aren’t telling.

Second, spells or items that interact with the other planes of existence operate at double efficiency. At the DM’s option, this increase can affect any aspect of a spell or item, and need not remain constant. That is, a spell’s range or area of effect, damage or duration could be doubled if used within the Cluster. One time it could be duration, the next range, depending on the whim of the DM. After all, there’s no telling just how the magical nature of Clusterspace will react at a given time.

Third, the Second Cataclysm caused certain barriers to be erected against the Outer Planes, and the Abyss in particular. Contact with the Outer Planes is very difficult, and spells that attempt to converse with a creature of those or travel outside of the Prime Material Plane will fail 25% of the time, —5%/level of the caster above 15th. Contact with the Abyss is virtually impossible. The barriers which keep characters from making contact with the Outer Planes also make it impossible for creatures of the Abyss to contact or come to this Plane (unless aided by Arcane servitors) and very difficult for other Outer Planar creatures to enter the Cluster.

Though very powerful, these planar barriers do not affect the spell-granting powers of the gods. The wizshades who erected the barriers had neither the power nor the inclination to separate the gods from those that worshipped them. Unfortunately for clerics, contacting a god is still restricted as above. Thus, priests have no difficulty receiving spells from their deity, but may not be able to contact such divine beings due to the barriers which seal the Cluster off from the Outer Planes.

Fourth and last, any characters who exit the Shattered Sphere via the other planes of existence and subsequently return to the Prime Material Plane will find themselves back within the Cluster. The wizshades used their combine power to create a powerful spell which binds the essence of those within the Cluster to the Prime Material Plane.

While a character may be able to move into planes other than the Prime Material, when he exits, he will always be in the exact location within the Cluster from which he left the Prime Material. In other words, if a character used a spell such as plane shift, and managed to successfully cast the spell (abiding by the penalties listed above) he could exit the Prime Material Plane and enter another. But no matter how far that character moved on that other plane and no matter how many other planes the character moved through, when he returns to the Prime Material Plane he will come back to the exact spot from which he had departed. Such is the nature of the crystal sphere surrounding the Astromundi Cluster.

Planetary Movement

The Cluster is a big place with scores of asteroids, planetoids, and other celestial bodies. The major celestial bodies are shown on the Planetary Display Map in their standard orbital patterns. DMs who desire simplicity can assume that all of the bodies represented on this map are locked into a synchronous orbit. That is, their distance and locations relative to one another do not change. This eliminates the need to keep track of planetary movement, easing that bit of the DM’s workload. It also allows easy calculation of distances and travel times.

It does not, however, give the flavor of a living, moving universe for the characters. DMs who desire a bit more complexity may use the following system to track the movements of the planets on the planetary display map.

The starting position of each of the celestial bodies must be determined at the start of the campaign. This is done using the method defined on p. 71 of The Concordance of Arcane Space included in the SPELLJAMMER® boxed set. Now, the DM should roll 1d4 for each body shown. On a roll of 1 or 2, that body moves in a clockwise direction around the primary sun, Firefall. On a roll of 3 or 4, the body moves in a counter-clockwise direction relative to the primary. Some celestial bodies have erratic orbits, and these are explained in Chapter Three.

Those celestial bodies on the outer track move approximately one space every 4 cycles. Since each space on the outer track is 400 million miles, variations in orbital speed are not a major factor.

Bodies on the inner track move somewhat quicker, averaging one space (30 million miles) every 10 days. Orbital speed variations matter here, so if the DM opts to alter the speed at which bodies orbit, he is advised to make note of the change.

Keeping track of where bodies are can be done with markers, or the DM can simply note down the location of planets at various dates in a notebook and refer to the notebook when celestial locations are important. The latter method requires more bookkeeping, but allows the players to use the planetary movement display for ship placement without revealing to them the location of every celestial body in the Cluster.

Ship movement is as detailed in the Concordance of Arcane Space, p. 72. Encounters are handled in the manner described in that book. DMs should note that characters within the Inner Ring have a –1 modifier to wildspace encounter checks because of the level of activity within the Inner Ring. Also, the entirety of Clusterspace is considered to be a system with extensive spelljamming, so all encounter checks receive another –1 to the roll (-2 total for all wildspace encounter checks in the Cluster). These modifiers are in addition to any other modifiers that may apply.

On Card #21 in this set is an encounter table suitable for use in the majority of the Cluster. Some modifications may be necessary if the characters are in heavily or very sparsely populated areas. If an encounter check calls for an encounter, roll percentile dice and consult that table.

Of course, this table does not contain every sort of encounter the characters could happen upon. In fact, it covers a scant handful of those encounters that could come to pass in the Cluster. DMs who wish to make changes or additions to this table should feel free to do so. After all, in the depths of wildspace, anything can happen.

Asteroids of the Cluster

The Astromundi Cluster has thousands upon thousands of asteroids scattered throughout. There are many different types of these celestial bodies, some of which are described below.

Animate Asteroids

An asteroid field

The Astromundi Cluster has always been a sphere high in both violence and magical activity. The combination of these two often results in the creation of undead beings, either as an indirect result of magical battles or because a mage needs a large supply of disposable troops in a hurry. In many cases, these undead are either forgotten or misplaced by their creators and left to fend for themselves. This has led to the scattering of undead, alone or in small groups, throughout the Cluster.

These undead often float through space, clinging to one another in an attempt to find solid ground and continue their tasks. After weeks or months, the group coalesces into a tight bundle of undead creatures. Dust and small rocks coat the group of undead, and they eventually become dormant.

Such animate asteroids can be extremely dangerous if approached. The skeletons and zombies may become active at any time and will attack anyone who is too near them when they do. Animate asteroids are also called dead rocks” by experienced sailors. Though rare, the animate asteroids have led to a standard practice of firing harpoons or other projectiles into any asteroid that a spelljammer wants to approach. Of course, this led to some disagreements with living asteroids (see below).

Bone Clusters

There are a great many creatures in wildspace that are of massive dimensions. Such creatures typically live far out away from civilization and die the same way. Sometimes the bones of these creatures are so large that they become celestial bodies of their own. Typical bone clusters are less than a hundred feet across, but some are the result of several great creatures and can be thousands of feet across. Bone clusters are very useful because they are both lightweight and durable, making them ideal platforms for floating towns or outposts. And all that talk about the spirits of the dead haunting them is just talk, right?


Occasionally, gases will coalesce around a solid core of a rock or ice asteroid. These gasteroids are dangerous to investigate, because quite often the gases they are composed of are hazardous to intelligent life. Those that are comprised of beneficial gases, however, are highly prized and sought after. Two types of gas that may be found are listed below.

Flame gas

Flame gas is, as its name suggests, a highly flammable, volatile substance. It can be contained in pottery or glass containers. A rag is then wrapped around the container, lighted, and the whole is thrown toward an enemy. When the container strikes an opponent or the ground, it breaks. The gas comes into contact with the flames and a cloud of flame 5’ in diameter is the result. Anyone caught within the radius of the flame takes 1d6 points of damage. The main advantage of these weapons is not anti-personnel, but their ability to set fires to spelljamming ships. Flame gas appears as a murky brown vapor which smells of tar.

Growth gas

Growth gas doubles the speed at which plants reach maturity and bear fruit, but has no effect on living things other than plants. If used against plant-type monsters, the growth gas will heal 1d10 points of damage each round for 1d6 rounds, after which the gas dissipates. This healing can take the monster over its hit point maximum, as it causes rapid growth of the creature’s body.

Remote settlements will pay highly for containers of this gas which can help them survive without relying on outside sources of food. An uncompressed one gallon container can be planted deep within the soil, and as the gas slowly leaks into the soil a one acre plot of land will be affected. Growth gas is colorless and odorless.

Many other types of gas are possible, limited only by the imagination and desires of the DM.


Occasionally, abandoned spelljamming hulks drift in or near a gravity well (see Navigational Hazards, below). These wrecked vessels compress so tightly that they become essentially one mass. They are home to all manner of strange creatures, and large numbers of undead among the wrecks are not uncommon.

Dangerous as they are, Hulkships (as these accumulations of space detritus are known) also have a tendency to hold great, lost treasures, some dating as far back as pre-Cataclysmic times. Such prizes are naturally avidly sought after, making it quite likely that adventurers will find work exploring these ship graveyards.

Ice Asteroids

These are highly prized asteroids comprised of frozen water. Though they litter the Fringe, they are rare within the asteroid belts nearer to the suns. Because they represent one of the few natural supplies of water, ice asteroids are enormously expensive and the Thoric have a near-monopoly on their sale and transport.

Fortunately for the Thoric, there is little possibility of exhausting this resource: between the Glacier and the Fringe, there is enough ice to supply the Cluster for several thousand years at least. The expense of the ice is due to the difficulty of transporting it without losing half of it in the process (it has a tendency to melt and leave a trail of pretty, but worthless, water droplets).

Living Asteroids

There is nothing stranger in the Cluster than the mysterious living asteroids. They are apparently congregations of powerful psionicists who have retreated into a shell of rock and ice and become a single organism. They are normally content to float through space, exploring the interiors of their own minds and ignoring the presence of all others. However, if they are approached, it is possible to convince them to awaken and dispense their words of wisdom.

This has become harder and harder to do, mainly because some of these living asteroids have been hit by harpoons when paranoid sailors believed them to be animate asteroids. For a description of a living asteroid, see Phalangilon, in Chapter 3.

Rock Asteroids

Most asteroids are comprised of basic rock. They may contain minerals, or some pockets of ice or frozen gases, but for the most part, they’re just plain old rock. These are useful for building on, and if large enough, make good atmosphere anchors for floating colonies. Rock asteroids that contain mineral elements are the home of buzzjewels and, if large enough, dwarves or even the rare grav colony (see MC 9).

Navigational Hazards

The Astromundi Cluster is not your average crystal sphere, so it stands to reason that the wildspace of the Cluster is a bit stranger than the norm. Because of the Cataclysms and planar stresses the Cluster has experienced, traveling through wildspace has a number of hazards. Below, the most important of these hazards are described.

Gravity Wells

When the Cataclysms broke the planets apart, they also created a number of vortices that spin to this day. These vortices are gravity centers, and venturing too near to them can cause great difficulty for the unwary spelljammer.

Fortunately, gravity wells are not that hard to spot. Depending on the size and intensity of the well, they can often be seen from miles away, appearing as great swirling masses of space debris. When seen from afar, they are easy to navigate around. If they are not avoided, they can cause severe damage to a spelljamming craft.

Gravity wells come in three basic sizes. Small wells are less than a hex in size. Small wells cannot be seen until a ship is almost in the well itself. An Intelligence check at —3 is required to see a small gravity well that lies in the ship’s course. Medium wells are between one and two hexes in size and can be seen from quite a distance, requiring an Intelligence check to spot before a vessel actually enters the well’s area of effect. Large wells can run anywhere from three to five hexes in area and are almost impossible to miss; characters need only make an intelligence check at +2 to notice the swirling cloud of debris around the well before they are in its area of effect.

While the size of a well is important in seeing and steering around it, it is not so much the well’s size, but its intensity that determines the danger it presents to spelljamming craft and their crews. Ships that cross a well of any size at spelljamming speeds will be forced to slow to tactical speeds by the well.

Gravity well intensities are rated as either light, moderate, or severe. Wells with a light intensity have very little effect on a spelljamming craft, but they will force a drop in speed, reducing a ship’s SR by 1 for as long as the craft is in the well. If a vessel for some reason stops within a light gravity well’s area of effect, it may have some difficulty moving out.

A ship must have an SR of at least 2 (after the —1 modification for the effect of the gravity) in order to escape from the well. With that rating it will take 5 rounds to move out of the gravity well’s area of affect and proceed with normal spelljamming travel. Each additional point of SR lowers the time it takes to reach escape velocity” by 1 round. Gravity wells of light intensity are too weak to hold a dangerous amount of debris within their area of affect.

Medium intensity gravity wells are somewhat more hazardous, as they often have large chunks of debris swirling down into their centers. Such chunks have a tendency to impact with unwary spelljamming ships that enter the well’s area of affect. A craft that unwittingly finds itself within a gravity well of moderate intensity will have its SR reduced by 2 as long as it is within the well. During the time the ship is in the well, it will be attacked” by debris. Treat the debris impacts as light catapult attacks with a THACO of 16 and standard chance of a critical hit. The ship will be attacked by one such missile a round, reflecting the danger of whirling debris within the gravity well.

Spelljamming vessels that enter a medium intensity gravity well have their SR reduced by 2 during their time in the well. Ships that stop in a gravity well’s center will have to spend 7 rounds attempting to pull out of the well’s center. This assumes a ship with an SR of 2 (after the —2 modifier for the strength of the well), ships with a lower modified SR will be unable to escape the well. Ships with higher SR ratings reduce the time needed to escape the clutch of gravity by one round per point of SR above 2.

Severe intensity gravity wells are incredibly dangerous to the unwary. Should a vessel enter a severe gravity well, it will find itself hard-pressed to remain in one piece. The intensity of the well reduces the SR of any ship by 3 for as long as the vessel remains within the well.

The amount of debris present within a well of this intensity makes it very likely that ships will take significant damage. Every round that the craft is in the well it will be pummeled by celestial debris. To simulate this merciless pounding, for each round that a craft is within the well, roll an attack against it as if a heavy catapult with THACO of 17 were firing against it. A critical hit occurs on a roll of 18+.

Infinity Vines

The elves of the Astromundi Cluster use infinity vines as a major defense for their colonies. As a result, many ships which attack the elves become entangled in the vines. When these vessels pull away, large chunks of vine remain attached to the ships. The crews of these ships generally scrape the stuff off out in wildspace, leaving large patches of infinity vine scattered throughout the Cluster. Most of these are easy to spot and avoid, but a new strain of vine is much harder to detect.

Infinity Vines

Though much the same as a standard infinity vine for game purposes, the so-called midnight vines have begun to grow in as black as the depths of wildspace, making them very difficult to spot. Lookouts aboard spelljamming ships will have to make an Intelligence check at —6 in order to spot the stuff in time to avoid it. Otherwise, ships will sail directly into the vine and become entangled in its leathery tendrils.

The elves find all of this to be quite amusing and are rumored to be cultivating the midnight vine for their own use. Fortunately, the vine is still rare and is much more difficult to maintain than a standard infinity vine, which limits its usefulness to the elves.


Nothing is more frustrating than having your ship’s helm conk out, especially in the deeps of wildspace. And that is precisely why the Navigator’s Guild will pay huge fees to those who manage to chart the location of a new sargasso.

Sargassos are places of null magic, where the motive force of spelljamming does not function. They are invisible to the naked eye and are rarely marked on star charts. The Sargasso of Skulls is one of the few Sargassos with visible boundaries, though it is unknown just who marked it off from the surrounding areas of wildspace.

DMs should feel free to litter Sargassos about wildspace, though these areas should not become too common. When a ship enters a sargasso, its spell-jamming engines immediately die” and the ship drifts one tactical hex for every point of SR it had before the helm quit. This inertial effect places the character’s vessel well within a sargasso, making it very difficult to fly back out. Unprepared sailors caught in a sargasso will spend their final days there.

Escaping from a sargasso can be as simple as being spotted by another ship, which then fires a tow cable out to the unfortunates (often for a hefty fee), or as complex as tearing the helm loose from the ship, tying a rope to it and catapulting it and a mage out of the sargasso so that he can pull the ship free. The last method is quite extreme, and although it will work it will also reduce the SR of the ship by 2 (to a minimum of 1) until reseated by a trained professional.

Some Sargassos are nastier than the common type, and go by the moniker of Magekillers. Magekillers randomly drain a spell per hour from mages stranded within them, and when all the spells are gone they start in on the mage’s hit points, deducting 1d4 every eight hours the mage spends within the sargasso. Clerics are affected in the same way, though their spells are much easier to replace than a mage’s, as mages cannot study new spells while within a Magekillers sargasso.

Typical Sargassos are between 5 and 15 hexes across at their widest points, though some are much larger. Magekillers Sargassos are fortunately quite rare, but they are also much larger, ranging from 10 to 20 hexes or even larger.

Temporal Fugues

Everyone has heard the tale of Gilly Oldfellow, that intrepid explorer who ventured into a nebula and reappeared fifty years later, looking just the same as when he’d left. The tale of Gilly is more than nonsense, however, because such nebulae do indeed exist.

If a group of characters enter a temporal fugue, they will be moved forward in time, sometimes being transported through decades in the blink of an eye.

Characters that fall prey to these temporal glitches often feel disoriented and extremely tired while they remain within the fugue. For every hour that the characters spend in a fugue, 1d10 years pass in the outside world. If a group sleeps within a fugue, their dreams will invariably be of time passing them by, or of people they know in the outside world aging and dying before their eyes. But other than the time that passes in the outside world, characters suffer no ill effects from time spent in the fugue.

It is virtually impossible to detect a physical or visual difference between temporal fugues and nebulae. A detect magic or similar spell will reveal the sorcerous nature of these phenomenon from within, but there is no reliable way to detect a temporal fugue from the outside.

DMs should be cautioned about putting characters through such time distortions. Characters who jump forward in time may find themselves in a sphere ruled by illithids or tanar’ri — without ever having a chance to thwart the creatures’ plans!


Those undead that do not form themselves into animate asteroids may find a nice piece of asteroid to call home. Such undead sometimes grow in intelligence and cunning, often finding ways to disguise their asteroid to attract unsuspecting spelljammers that are then eaten. These asteroids are highly prized by necromancers, who seek them out to gain a quick army of relatively intelligent undead which can be used for a variety of nefarious purposes.


Occasionally someone tries to escape the Astromundi Cluster through the use of plane-breaching sorcery. Occasionally these attempts do work, but more often the inherent magic of the Cluster works to manipulate the magic to its own ends. Thus, there are many one-way vents into the Astromundi Cluster. These portals allow creatures from other spheres and other planes of existence (though never the Abyss) one way-access to the Astromundi Cluster.

Vents are dangerous to characters because there’s just no telling what sort of nasty critter will crawl out. Things coming out of a vent are in danger because the intelligent races of the Shattered Sphere are liable to attack anything that crawls out of the vent and worry about whether it was hostile or not later.

Vents appear as pale blue ovals that seem to wink in and out. When active (that is, when something is passing through them), background scenes from various planes of existence can be seen through them. Unlike a wrinkle, (see below) there is space in a vent, and they can often take several days to travel through. Such journeys are surreal and unnerving as those within the vent are witness to scenes taking place in the planes they move through.

Wild Zones

Some areas of wildspace are also areas of wild magic (see FORGOTTEN REALMS® Adventures and Tome of Magic).

These operate just as they do in a groundling campaign, including wild surges. The difference in a spelljamming campaign is that characters in a spelljamming helm are essentially using magic constantly. Such characters cause a wild surge every turn they travel through a wild zone, making life aboard the ship quite chaotic. Wild zones seem to shimmer a bit from the outside, but once a character or group of characters are within the zone their surroundings appear normal. Most wild zones are 3 to 6 hexes across at their widest point.


The existence of these particular navigational hazards is not common knowledge. The illithids believe that they exist and the Arcane know that wrinkles exist, but few others have a clue.

Wrinkles are distortions of space and time that tie two distant points together. Entering a wrinkle from either end will immediately transport you to the other, often making a long trip extremely short. While it seems that these would be ideal trade routes, wrinkles are extremely hard to detect. Many travelers have passed right through a wrinkle and not realized it, until they checked their star charts and found themselves millions of miles off course. Another quirk of wrinkles is that they are not all permanent, and some move from one area to another. Also, a wrinkle that works one way may not work the other, stranding characters in the far reaches of wildspace.

Arcane theorists suppose that a reason the wrinkles are so hard to find is that many of them have their exits in the heart of Firefall, Denaeb, or in other hazardous areas. Thus, explorers may have found many wrinkles and simply never lived to tell about them.

These strange portals vary widely in their appearance, from fiery holes in space to innocuous shimmering veils. In most cases, there is no space between the two ends of a wrinkle. That is, when a craft enters a wrinkle, it is already coming out the other side with no sensation of time spent within the wrinkle itself.

Wrinkles are a DM’s toy, a way to get characters from one place to another quickly and without letting them know exactly what is going on. They can also serve as the focus of several adventures as characters are charged with tracking down wrinkles and charting their paths for the illithids or Arcane.

There’s no telling what the characters may find on the ends of some of these twisted little time/​space tunnels, so here’s a chance for DMs to really go all out!

Other hazards are surely present within the sphere, but are not as common as those listed above. DMs are encouraged to come up with mysterious danger zones of their own, keeping an aura of mystery about the Cluster and keeping the players on their toes.


Right-click and choose "Save link target as" for the .markdown files.