Athasian Disk Calendar

 

Athasian Disc Calendar. 

Dropbox link to pdf:

 https://www.dropbox.com/s/ebbme5hyvh069qs/print%20to%20pdf%20athas%20disc%20calendar%20v1.31.pdf?dl=0

 This calendar could be something you would find on Athas that people would use to keep track of dates, years, and phases of the moons.  This calendar in an amalgam of the Merchant’s Calendar and many of the other astronomical data presented in Dark Sun. It also serves as an improved version of the Two Moon Calendar mentioned in Trade Lords, allowing players to quickly calculate when moons are full or new to help with planning night-time activities. 

 

It is based on a 125-day Guthay cycle and a 33-day Ral cycle as presented in the Merchant Calendar program. Found here:

http://www.athas.org/articles/the-merchant-s-calendar

No official 2e Dark Sun product ever detailed out the periods of the phases of the moons, and I think the author of that program did a nice job of it. It seems to be the most widely accepted program for that purpose, so I patterned my calendar after it somewhat. (Even though I believe there could be other acceptable periods of the moons.)  I like the program because it is based on physics for plausible cycles of the two moons

 

When operated correctly this disk calendar should follow the Merchant Calendar program very closely. Think of it as an actual useable calendar that an Athansian could use. I may have a few lines slightly off centered and whatnot, but if you check my calendar with what is presented there you will find a close agreement. 

 

The calendar consists of three different discs: a Base Disc, a Ral Moon Disc, and a Sofean cycle Indicator disc.  It also includes two needles.

 

Operating the calendar:

It is usually easiest to keep the High Sun at the top of the disc to first orient yourself. It is also helpful to think as though you are standing in the middle of the ring and then rotate the whole disc to the desired month/moon phase/constellation/date so that it is now at the top. Also, note all moons are assumed to wax from the right side to the left. (i.e. Waxing the right side is light up, waning the left side is light up.)  Ergo, this assumes a northern hemisphere location for the cities Athas. Sorry, I did not make this consistent for those who may be used to a southern hemisphere / moon-in-the-north-sky / upside-down-moon/ opposite-waxing and waning-moon. That may be my northern hemisphere privilege showing through. (Though admittedly, I am under the assumption that when the creators of Dark Sun designed it, they did so with a northern hemisphere location in mind.)

Though many lunar calendars in Earth’s history start on a new moon, and not a full moon, this calendar system starts the calendar system with two full moons that are in conjunction on the same day as the summer solstice (High Sun). This cycle repeats every 11 years.

Listed in order from outer most edger to inside

BASE DISC

This disc is made of several concentric rings that have various pieces of information detailed throughout. 

Month Ring – This ring has the names of all 15 months of the Merchant’s Calendar aligned with the days of the years they fall on.

Day of Month Ring – This ring has every 5^th day identified of each month. It includes all 375 days – (I wasn’t going to identify all 375 of these so I only did every 5^th day.)

Day of Year Ring – This ring has every 5^th day of the year marked of 375 days. Again, I didn’t want to detail all 375 of them so I did every 5^th.  This is useful to subtract two dates from each other to know how many days apart they are.

Constellation Name Ring – This ring contains all the names of the constellations corresponding to when they fall in the year. This was taken from The Ivory Triangle. This ring also has part of the indicator for Sun Ascending, Sun Descending, High Sun, and Low Sun. Please also notice that High Sun is placed above the line and Low Sun is placed below the line. And the equinoxes are placed on the line.

Constellation Pattern Ring – Has all the shapes of the constellations in the Zodiac. The idea here is that if you know what constellation is in the sky you should be able to figure out the month and day you are in by the phases of the moons.

Guthay Phases Ring – has the phases of Guthay throughout the year. Since Guthay has an exact 125 days between full moons, it means that there are exactly 3 full moons of Guthay in a year on Athas.

Inner Ring – this is the interior portion of the base ring and will mostly be covered by the top discs except for where the upper discs have cutout. The left side includes the names of the Endlean cycles. They are also numbered 1-11.  Each has an arrow that is lined up with the arrow on the Ral Disc depending on the cycle you are in. – more on that in the Ral Disc.

This ring also includes the information for the Free Year that corresponds to the equivalent year of the Sofean cycle. Starting with FY 1, in Priest’s Defiance, the 77 unique combinations of Endlean and Sofean that correspond to the Free Year are found here. I started with FY1 since I figured that most campaigns will want to start at or around FY1.  It is possible to convert to other years prior to FY1 by just adding or subtracting 77 from the number listed on the disc.  I.e 77 becomes FY 0.  76 become FY -1. 

Alternatively, if you want the corresponding King’s Age/Year, you can add 25 to the number displayed on the disc.

The other items on there is an image of the two moons in conjunction (occultation) which will be revealed every 11 years, i.e. every time there is a year of Ral in the Endlean cycle. There also is two images of the comet the Messenger, which appears in the year of FY7 and FY52.

It would be possible to have other base discs created or at least this portion that match other periods in the game, but hopefully this is the most useful time period.

 

RAL MOON DISC

This disc has the phases of the moon Ral for an entire year. The indicator at the top with the arrow is aligned with the specific Endlean cycle. This ring will rotate counter-clockwise each year to a new cycle and then at the end of the eleventh year will return to the first year.  Reading of the moons follows a clockwise direction as the year progresses.

Because the number of full moons in a year is not exactly divisible into a year, when the last full moon on this disc is reached, you jump down to the lower portion and follow it until the year is completed.  The phase of the moon, Ral, at the beginning of the year will always be initially indicated by the outer phases of the ring. Starting with the one that is aligned with line running from the center of the ring to Highest Sun.  

Eclipse indicator.

I may add other info to the disc later.

SOFEAN CYCLE DISC.

This disc includes the names of the Sofean cycle that correspond to the Free Year.  More detail needed.

Messenger indicator for the two years that it occurs between FY1 and FY77

NEEDLES

Used to provide a straight line from the center of the map to the edge of the map.  Using the day of the year ring, one can be subtracted from another to determine how many days away an event is.

If the needle is pointed to the correct day, the edge of the needle (colored edge, running to the center brad) will indicate the phase of  Guthay.  If the Ral ring is set to the correct Endlean cycle, then the edge of the needle will also indicate the correct phase of Ral.    

ASSEMBLING THE CALENDAR

You will need:

8.5 x 11 card stock. 2 pages to print it on.

A small brad or pin.  I’ve used the smallest Brad I could find. If you use a pin, you may need some backer board or something to stick it in.

Scissors to make all the cutouts of the hatch marks

A standard paper hole punch. –

Assemble them in from largest on the bottom to smallest on top with the two needles last.

I had some problems printing it and it is a tight fit on an 8.5 x 11 page.  I recommend printing it with cardstock or photopaper.  Cutting it will scissors and an exacto knife and using a three hole punch for the small holes.  you will need a pin or a small brad for the middle that goes through the exact center of each circle.  if it is punched correctly the circles will line up.