Anyone an Astronomy/Math major? [Archive] - Wizards Community

Anyone an Astronomy/Math major? [Archive] - Wizards Community

Post/Author/DateTime Post
davethebrave371
10-07-05, 09:54 PM When, based on the Eberron Cosmology (http://www.wizards.com/default.asp?x=dnd/ebwe/20041129a) would there last have been all new moons, and when was there the most new moons in the last 150 years? I'd figure it out, only I don't know how. I'm an English and History major.
Tarionz_Cousin
10-07-05, 11:49 PM One of my players might be able to do this. He loves math and astronomy.

However, :thinks: I won't see him for a week or two, so someone else might be able to give you an answer before then.

--T, English and Education
davethebrave371
10-08-05, 01:23 PM One of my players might be able to do this. He loves math and astronomy.

However, :thinks: I won't see him for a week or two, so someone else might be able to give you an answer before then.

--T, English and Education

Well, when and if he can get on the boards or tell you, that'd be swell and a half! Also, I plan to teach English and History in high school, what are you doing with your Education degree?
Tarionz_Cousin
10-09-05, 11:34 AM I taught "Language Arts," which is essentially English for grades 7-8 for a while. For most of the past 6 years I've been a Business Trainer. I've taught classroom and individual style for companies.

Right now I'm working in Accounting, using my math skills. But I'm working toward being a Writer or Trainer at my current company.

Good luck teaching.

I'll talk to my Astronomy/Math player this week and see what he can come up with.
DanjaNinja
10-09-05, 04:44 PM I can tell you how to do it, but I have no inclination to do it myself. First, figure out the period of all twelve moons (that is, how many days it takes for the moon to go from full to new to full again). I'll call each individual period P1, P2, P3, etc... Next, choose an arbitrary starting point (1 Zarantyr 998, for example) and figure out how many days into their periods each moon is. I'll call these C1, C2, C3, etc (it's important that each C and each P correspong to the same moon, BTW)... Okay, now set up an equation as follows:

(|x-C1| mod P1) - (|x-C2| mod P2) - (|x-C3| mod P3) ... = 0
|x| means the absolute value of x, and mod is the modulo operator (http://en.wikipedia.org/wiki/Modulo_operation). Solve for x to find when all the moons were full. A negative x is days before the starting point, and a positive x is days after. The best way is probably to graph the above equation (there's many free graphing utilities hanging around in the web) and find the x-intercepts (there will be more than one).

Edit: I fixed a glaring error in my original equation. :embarrass
davethebrave371
10-09-05, 05:58 PM I can tell you how to do it, but I have no inclination to do it myself. First, figure out the period of all twelve moons (that is, how many days it takes for the moon to go from full to new to full again). I'll call each individual period P1, P2, P3, etc... Next, choose an arbitrary starting point (1 Zarantyr 998, for example) and figure out how many days into their periods each moon is. Add that all up (I'll call the sum S). Okay, now set up an equation as follows:

S - (|x| mod P1) - (|x| mod P2) - (|x| mod P3) ... = 0
|x| means the absolute value of x, and mod is the modulo operator (http://en.wikipedia.org/wiki/Modulo_operation). Solve for x to find when all the moons were full. A negative x is days before the starting point, and a positive x is days after. The best way is probably to graph the above equation (there's many free graphing utilities hanging around in the web) and find the x-intercepts (there will be more than one).

...wow. Uhhh...I really don't know what any of that means. Thank you for the info, for sure. But I haven't done math since Grade 11. I really don't know what any of that means.
DanjaNinja
10-09-05, 06:19 PM Could you be a little more specific about what's confusing you? I'm assuming it's not the part about finding the periods and taking sums, but rather the actual equation itself.

What's the highest level of math you took, and rougly how much of it do you remember?
davethebrave371
10-09-05, 06:59 PM Could you be a little more specific about what's confusing you? I'm assuming it's not the part about finding the periods and taking sums, but rather the actual equation itself.

What's the highest level of math you took, and rougly how much of it do you remember?

In my high school, there were 3 levels of Math: Essentials, Applications and Principles. Essentials was essentially for troubled kids, the mentally handicapped and ESL students who couldn't keep up with Applications or Principles. I took Essentials, because Math is not a prereq to anything I take in College or University, and I knew that at the time. So, essentially, the highest level of math I took was Math 9, because that was harder than Essentials 11. And I don't remember any of it all that well. I got an A, but it was an A due to the insane ease of the course, not because it taught me anything.

As for what I don't understand, everything past "twelve moons" is confusing to me.
DanjaNinja
10-09-05, 07:17 PM Ah, sorry then. I mean, it's not a terribly difficult problem, just a little heavy on the arithmetic (I'd do it if I weren't so lazy). If you think you're up to it, I'd recommend brushing up on algebra and familiarizing yourself with GraphCalc (http://www.graphcalc.com/).
Thomar_of_Uointer
10-09-05, 07:55 PM You would take the Lowest Common Denominator of the orbital periods (find the lowest factors of all the periods, throw out anything if it shows up a second time, then multiply it all). As a DM, you have control over when it happened last and when it happens next. However, I can't seem to find any actual numbers for the orbital periods...
DanjaNinja
10-09-05, 10:16 PM You would take the Lowest Common Denominator of the orbital periods (find the lowest factors of all the periods, throw out anything if it shows up a second time, then multiply it all). As a DM, you have control over when it happened last and when it happens next. However, I can't seem to find any actual numbers for the orbital periods...
That's actually the Least Common Multiple. :)
And you couldn't throw out periods of equal amounts unless both moons happened also to be at the same spot in their period. Also, this would tell you how many days between each occurence there was, but not when it would next (or last) happen.
davethebrave371
10-10-05, 03:26 PM That's actually the Least Common Multiple. :)
And you couldn't throw out periods of equal amounts unless both moons happened also to be at the same spot in their period. Also, this would tell you how many days between each occurence there was, but not when it would next (or last) happen.

See, this is why I can't do this stuff!
Tom McCarthy
10-11-05, 11:07 AM I've done the math, many months ago. You'll never find a date when all the moons are new. You'll rarely find many of them new. You can find them all full, but that was way back on New Year's Day of the year the first dragonmarks appeared.
cmanos
10-11-05, 12:51 PM I believe a couple of the moons are on diametrically opposed schedules, so one will be full when the other is new...always....need to check this
davethebrave371
10-12-05, 12:29 AM I've done the math, many months ago. You'll never find a date when all the moons are new. You'll rarely find many of them new. You can find them all full, but that was way back on New Year's Day of the year the first dragonmarks appeared.

Never? Are you sure? That seems...almost impossible.
Streamweaver
10-12-05, 10:49 AM Never? Are you sure? That seems...almost impossible.

It stands to reason that if there is a period where all moons can be full then there is a period where all moons will be new.
Dragonmann
10-12-05, 12:22 PM You can also look at the Web Enhancement they did, which has the eberron calandar, moon phases, and plane positions plotted out.

http://wizards.com/default.asp?x=dnd/ebwe/20041129a

It takes some clicking, but you can fins out if it is possible or not.
mefron
10-12-05, 12:37 PM I've already done all the calculations. Here is a message I posted on my campaign's site:

As another point of interest, the next time all the moons will be full at the same time is on 6-28-5305 and this event should last about three days.

I'm beginning to see a pattern. It looks like 6-28 is a special day because many lunar events happen on this day.

Actually since year 0 the first ever 12 full moon event will be on 6-28-5305. What a special day that will be.

As for when there will be all new moons, I have searched from 0YK upto 100,000 YK and have found no date in which all the moons are new. In fact at most I found only seven new moons (and in 100,000 years only 52 such days occur).
slainethehornedgod
10-12-05, 12:59 PM Actually since year 0 the first ever 12 full moon event will be on 6-28-5305.

Wouldn't it make sense that all new moons would be directly in the middle of the full moon pattern? So sometime in 2652?
mefron
10-12-05, 01:09 PM Wouldn't it make sense that all new moons would be directly in the middle of the full moon pattern? So sometime in 2652?

No, not nescessarily. Feel free to look for yourself but such a day does not exist. Besides you would want the middle of times when the moons were full. The moons were not all full in year 0 (or 1). You would have to use the last time they were full as your starting point.

I expenaded my search to upto 1,000,000 YK and still I can only find at most seven simultaneous new moons.
slainethehornedgod
10-12-05, 01:34 PM Oh, I looked at the luner cycles a bit more closely and it appears that not all the moons are on a 28 day cycle. For example, Therendor is full for 4 days every 42 days. The moons Olarune, Eyre, Vult, Zarantyr, Aryth, Dravago, Lharvion and Barrakas also appear to not be monthly and I'd be willing to bet they are all on slightly different cycles. I hadn't realized that.

With that in mind I would think the chance that all the moons would naturally come into the same phase at the same time would be pretty remote. If non-existant.

Of course as a DM you could simply make it how you want. Or have a NPC use some kind of eldrich machine or magic ritual to do it.
mefron
10-12-05, 01:38 PM I've proven it mathematically (to myself), it is impossible for all the moons to be new at the same time. The main reason for this is that all the moons have periods which are perfect and are multiples of seven (28, 35, 43, 49, 56, 63, 70, 77, 84, 91, 98, and 105). When doing the math you end up with something like:
28 * K1 - 35 * K2 = 3.5 where K1 and K2 are integers. Obviously there is no solution for K1 and K2.
davethebrave371
10-12-05, 08:53 PM I've proven it mathematically (to myself), it is impossible for all the moons to be new at the same time. The main reason for this is that all the moons have periods which are perfect and are multiples of seven (28, 35, 43, 49, 56, 63, 70, 77, 84, 91, 98, and 105). When doing the math you end up with something like:
28 * K1 - 35 * K2 = 3.5 where K1 and K2 are integers. Obviously there is no solution for K1 and K2.

For my own curiosity, and because I'm horrible at math, could you answer me this question, please?

When is the date where the most moons are new between the years 863-885, and how many moons is that?
mefron
10-13-05, 10:09 AM For my own curiosity, and because I'm horrible at math, could you answer me this question, please?

When is the date where the most moons are new between the years 863-885, and how many moons is that?

There are five days where five of the moons are new in the period you asked about:

865 YK:
Vult 16: Nymm Rhaan Eyre Zarantyr Barrakas
Vult 18-19: Sypheros Rhaan Eyre Zarantyr Barrakas

869 YK:
Dravago 25-26: Sypheros Olarune Zarantyr Lharvion Barrakas

Dravago in 869 is a very dark month and if that's what you're looking for than that's your best choice.
davethebrave371
10-13-05, 09:30 PM There are five days where five of the moons are new in the period you asked about:

865 YK:
Vult 16: Nymm Rhaan Eyre Zarantyr Barrakas
Vult 18-19: Sypheros Rhaan Eyre Zarantyr Barrakas

869 YK:
Dravago 25-26: Sypheros Olarune Zarantyr Lharvion Barrakas

Dravago in 869 is a very dark month and if that's what you're looking for than that's your best choice.

Thank you very much! One of the characters in my group wanted his birthday on a moonless or mostly moonless night, and this works great. As his DM, I like to be able to seem all-knowing about some things, but I just couldn't find it on the calendar! Thanks again!
Streamweaver
10-13-05, 10:16 PM Having Mefron as a player in my game I'm lucky to have his math skills available for such questions as well. I keep prodding him for some more details and sometime I think we intend to put up some kind of expanded version of an Eberron Lunar utility on our campaign site. Then if we did everything we wanted and even planned to do, we'd be a game publishing house in our own right. Hope our desire always outpaces our time and all but so many good things, so little time.
mefron
10-14-05, 12:32 PM Here are the moons, and the number of days each spends in a particular phase.

Here's the key to the phases:
N New
XC Waxing Crescent
FQ First Quarter
XG Waxing Gibbous
F Full
WG Waning Gibbous
LQ Last Quarter
WC Waning Crescent

Moon Period N XC FQ XG F WG LQ WC
Zarantyr 77 8.25 11 8.25 11 8.25 11 8.25 11
Olarune 56 6 8 6 8 6 8 6 8
Therendor 42 4.5 6 4.5 6 4.5 6 4.5 6
Eyre 63 6.75 9 6.75 9 6.75 9 6.75 9
Dravago 91 9.75 13 9.75 13 9.75 13 9.75 13
Nymm 28 3 4 3 4 3 4 3 4
Lharvion 98 10.5 14 10.5 14 10.5 14 10.5 14
Barrakas 105 11.25 15 11.25 15 11.25 15 11.25 15
Rhaan 49 5.25 7 5.25 7 5.25 7 5.25 7
Sypheros 35 3.75 5 3.75 5 3.75 5 3.75 5
Aryth 84 9 12 9 12 9 12 9 12
Vult 70 7.5 10 7.5 10 7.5 10 7.5 10

Forgive the formatting. BBCode doesn't allow tables or pre-formatted sections.
davethebrave371
10-14-05, 01:34 PM Here are the moons, and the number of days each spends in a particular phase.

Here's the key to the phases:
N New
XC Waxing Crescent
FQ First Quarter
XG Waxing Gibbous
F Full
WG Waning Gibbous
LQ Last Quarter
WC Waning Crescent

Moon Period N XC FQ XG F WG LQ WC
Zarantyr 77 8.25 11 8.25 11 8.25 11 8.25 11
Olarune 56 6 8 6 8 6 8 6 8
Therendor 42 4.5 6 4.5 6 4.5 6 4.5 6
Eyre 63 6.75 9 6.75 9 6.75 9 6.75 9
Dravago 91 9.75 13 9.75 13 9.75 13 9.75 13
Nymm 28 3 4 3 4 3 4 3 4
Lharvion 98 10.5 14 10.5 14 10.5 14 10.5 14
Barrakas 105 11.25 15 11.25 15 11.25 15 11.25 15
Rhaan 49 5.25 7 5.25 7 5.25 7 5.25 7
Sypheros 35 3.75 5 3.75 5 3.75 5 3.75 5
Aryth 84 9 12 9 12 9 12 9 12
Vult 70 7.5 10 7.5 10 7.5 10 7.5 10

Forgive the formatting. BBCode doesn't allow tables or pre-formatted sections.

You sir, are a gem for any gaming group to place in it's crown. :bow:
mefron
10-14-05, 01:56 PM Here is the revised chart. I engineered it to perfectly match the Eberron calendar posted online although careful examinination of this data will reveal strange lunar behavior.

The numbers in the columns represent the day of that moon's cycle it will become the given phase. For example Zarantyr is new on days 1 through 7 of its phase and full on days 27 through 39 of its phase.

The seed number is the day in phase on 1/1/998. Other seed values can easily be computed for any other day.

To use this chart just keep track of twelve numbers (one for each moon) incrementing them (by one) for each game day. Set the numbers back to 1 whenever you exceed that moon's period. Refer to this chart to translate those numbers into phases.

Moon Period Seed N XC FQ XG F WG LQ WC N
Zarantyr 77 16 1 8 20 27 40 47 59 66 78
Olarune 56 34 1 6 14 19 31 36 44 49 57
Therendor 42 25 1 5 11 15 23 27 33 37 43
Eyre 63 14 1 7 17 23 32 38 48 54 64
Dravago 91 87 1 9 23 31 48 56 70 78 92
Nymm 28 16 1 4 8 11 15 18 22 25 29
Lharvion 98 96 1 10 26 35 49 58 74 83 99
Barrakas 105 61 1 10 26 35 56 65 81 90 106
Rhaan 49 19 1 5 13 17 25 30 38 42 50
Sypheros 35 19 1 4 10 13 17 21 27 30 36
Aryth 84 45 1 9 23 31 41 49 63 71 85
Vult 70 38 1 7 19 25 34 41 53 59 71

A more realistic chart would look like this (the same rules and seed numbers apply):

Moon Period N XC FQ XG F WG LQ WC
Zarantyr 77 1 9 20 28 39 47 58 67 78
Olarune 56 1 7 15 21 29 35 43 49 57
Therendor 42 1 5 11 16 22 26 32 37 43
Eyre 63 1 7 16 23 32 39 48 55 64
Dravago 91 1 10 23 33 46 56 69 79 92
Nymm 28 1 4 8 11 15 18 22 25 29
Lharvion 98 1 11 25 36 50 60 74 85 99
Barrakas 105 1 12 27 38 53 64 79 91 106
Rhaan 49 1 6 13 18 25 30 37 43 50
Sypheros 35 1 4 9 13 18 22 27 31 36
Aryth 84 1 10 22 31 43 52 64 73 85
Vult 70 1 8 18 26 36 43 53 61 71

Use whichever set you want.
davethebrave371
10-14-05, 02:22 PM Here is the revised chart. I engineered it to perfectly match the Eberron calendar posted online although careful examinination of this data will reveal strange lunar behavior.

The numbers in the columns represent the day of that moon's cycle it will become the given phase. For example Zarantyr is new on days 1 through 7 of its phase and full on days 27 through 39 of its phase.

The seed number is the day in phase on 1/1/998. Other seed values can easily be computed for any other day.

To use this chart just keep track of twelve numbers (one for each moon) incrementing them (by one) for each game day. Set the numbers back to 1 whenever you exceed that moon's period. Refer to this chart to translate those numbers into phases.

Moon Period Seed N XC FQ XG F WG LQ WC N
Zarantyr 77 16 1 8 20 27 40 47 59 66 78
Olarune 56 34 1 6 14 19 31 36 44 49 57
Therendor 42 25 1 5 11 15 23 27 33 37 43
Eyre 63 14 1 7 17 23 32 38 48 54 64
Dravago 91 87 1 9 23 31 48 56 70 78 92
Nymm 28 16 1 4 8 11 15 18 22 25 29
Lharvion 98 96 1 10 26 35 49 58 74 83 99
Barrakas 105 61 1 10 26 35 56 65 81 90 106
Rhaan 49 19 1 5 13 17 25 30 38 42 50
Sypheros 35 19 1 4 10 13 17 21 27 30 36
Aryth 84 45 1 9 23 31 41 49 63 71 85
Vult 70 38 1 7 19 25 34 41 53 59 71

A more realistic chart would look like this (the same rules and seed numbers apply):

Moon Period N XC FQ XG F WG LQ WC
Zarantyr 77 1 9 20 28 39 47 58 67 78
Olarune 56 1 7 15 21 29 35 43 49 57
Therendor 42 1 5 11 16 22 26 32 37 43
Eyre 63 1 7 16 23 32 39 48 55 64
Dravago 91 1 10 23 33 46 56 69 79 92
Nymm 28 1 4 8 11 15 18 22 25 29
Lharvion 98 1 11 25 36 50 60 74 85 99
Barrakas 105 1 12 27 38 53 64 79 91 106
Rhaan 49 1 6 13 18 25 30 37 43 50
Sypheros 35 1 4 9 13 18 22 27 31 36
Aryth 84 1 10 22 31 43 52 64 73 85
Vult 70 1 8 18 26 36 43 53 61 71

Use whichever set you want.

Danke once again.

Post/Author/DateTime	Post
davethebrave371 10-07-05, 09:54 PM	When, based on the Eberron Cosmology (http://www.wizards.com/default.asp?x=dnd/ebwe/20041129a) would there last have been all new moons, and when was there the most new moons in the last 150 years? I'd figure it out, only I don't know how. I'm an English and History major.
Tarionz_Cousin 10-07-05, 11:49 PM	One of my players might be able to do this. He loves math and astronomy. However, :thinks: I won't see him for a week or two, so someone else might be able to give you an answer before then. --T, English and Education
davethebrave371 10-08-05, 01:23 PM	One of my players might be able to do this. He loves math and astronomy. However, :thinks: I won't see him for a week or two, so someone else might be able to give you an answer before then. --T, English and Education Well, when and if he can get on the boards or tell you, that'd be swell and a half! Also, I plan to teach English and History in high school, what are you doing with your Education degree?
Tarionz_Cousin 10-09-05, 11:34 AM	I taught "Language Arts," which is essentially English for grades 7-8 for a while. For most of the past 6 years I've been a Business Trainer. I've taught classroom and individual style for companies. Right now I'm working in Accounting, using my math skills. But I'm working toward being a Writer or Trainer at my current company. Good luck teaching. I'll talk to my Astronomy/Math player this week and see what he can come up with.
DanjaNinja 10-09-05, 04:44 PM	I can tell you how to do it, but I have no inclination to do it myself. First, figure out the period of all twelve moons (that is, how many days it takes for the moon to go from full to new to full again). I'll call each individual period P1, P2, P3, etc... Next, choose an arbitrary starting point (1 Zarantyr 998, for example) and figure out how many days into their periods each moon is. I'll call these C1, C2, C3, etc (it's important that each C and each P correspong to the same moon, BTW)... Okay, now set up an equation as follows: (\|x-C1\| mod P1) - (\|x-C2\| mod P2) - (\|x-C3\| mod P3) ... = 0 \|x\| means the absolute value of x, and mod is the modulo operator (http://en.wikipedia.org/wiki/Modulo_operation). Solve for x to find when all the moons were full. A negative x is days before the starting point, and a positive x is days after. The best way is probably to graph the above equation (there's many free graphing utilities hanging around in the web) and find the x-intercepts (there will be more than one). Edit: I fixed a glaring error in my original equation. :embarrass
davethebrave371 10-09-05, 05:58 PM	I can tell you how to do it, but I have no inclination to do it myself. First, figure out the period of all twelve moons (that is, how many days it takes for the moon to go from full to new to full again). I'll call each individual period P1, P2, P3, etc... Next, choose an arbitrary starting point (1 Zarantyr 998, for example) and figure out how many days into their periods each moon is. Add that all up (I'll call the sum S). Okay, now set up an equation as follows: S - (\|x\| mod P1) - (\|x\| mod P2) - (\|x\| mod P3) ... = 0 \|x\| means the absolute value of x, and mod is the modulo operator (http://en.wikipedia.org/wiki/Modulo_operation). Solve for x to find when all the moons were full. A negative x is days before the starting point, and a positive x is days after. The best way is probably to graph the above equation (there's many free graphing utilities hanging around in the web) and find the x-intercepts (there will be more than one). ...wow. Uhhh...I really don't know what any of that means. Thank you for the info, for sure. But I haven't done math since Grade 11. I really don't know what any of that means.
DanjaNinja 10-09-05, 06:19 PM	Could you be a little more specific about what's confusing you? I'm assuming it's not the part about finding the periods and taking sums, but rather the actual equation itself. What's the highest level of math you took, and rougly how much of it do you remember?
davethebrave371 10-09-05, 06:59 PM	Could you be a little more specific about what's confusing you? I'm assuming it's not the part about finding the periods and taking sums, but rather the actual equation itself. What's the highest level of math you took, and rougly how much of it do you remember? In my high school, there were 3 levels of Math: Essentials, Applications and Principles. Essentials was essentially for troubled kids, the mentally handicapped and ESL students who couldn't keep up with Applications or Principles. I took Essentials, because Math is not a prereq to anything I take in College or University, and I knew that at the time. So, essentially, the highest level of math I took was Math 9, because that was harder than Essentials 11. And I don't remember any of it all that well. I got an A, but it was an A due to the insane ease of the course, not because it taught me anything. As for what I don't understand, everything past "twelve moons" is confusing to me.
DanjaNinja 10-09-05, 07:17 PM	Ah, sorry then. I mean, it's not a terribly difficult problem, just a little heavy on the arithmetic (I'd do it if I weren't so lazy). If you think you're up to it, I'd recommend brushing up on algebra and familiarizing yourself with GraphCalc (http://www.graphcalc.com/).
Thomar_of_Uointer 10-09-05, 07:55 PM	You would take the Lowest Common Denominator of the orbital periods (find the lowest factors of all the periods, throw out anything if it shows up a second time, then multiply it all). As a DM, you have control over when it happened last and when it happens next. However, I can't seem to find any actual numbers for the orbital periods...
DanjaNinja 10-09-05, 10:16 PM	You would take the Lowest Common Denominator of the orbital periods (find the lowest factors of all the periods, throw out anything if it shows up a second time, then multiply it all). As a DM, you have control over when it happened last and when it happens next. However, I can't seem to find any actual numbers for the orbital periods... That's actually the Least Common Multiple. :) And you couldn't throw out periods of equal amounts unless both moons happened also to be at the same spot in their period. Also, this would tell you how many days between each occurence there was, but not when it would next (or last) happen.
davethebrave371 10-10-05, 03:26 PM	That's actually the Least Common Multiple. :) And you couldn't throw out periods of equal amounts unless both moons happened also to be at the same spot in their period. Also, this would tell you how many days between each occurence there was, but not when it would next (or last) happen. See, this is why I can't do this stuff!
Tom McCarthy 10-11-05, 11:07 AM	I've done the math, many months ago. You'll never find a date when all the moons are new. You'll rarely find many of them new. You can find them all full, but that was way back on New Year's Day of the year the first dragonmarks appeared.
cmanos 10-11-05, 12:51 PM	I believe a couple of the moons are on diametrically opposed schedules, so one will be full when the other is new...always....need to check this
davethebrave371 10-12-05, 12:29 AM	I've done the math, many months ago. You'll never find a date when all the moons are new. You'll rarely find many of them new. You can find them all full, but that was way back on New Year's Day of the year the first dragonmarks appeared. Never? Are you sure? That seems...almost impossible.
Streamweaver 10-12-05, 10:49 AM	Never? Are you sure? That seems...almost impossible. It stands to reason that if there is a period where all moons can be full then there is a period where all moons will be new.
Dragonmann 10-12-05, 12:22 PM	You can also look at the Web Enhancement they did, which has the eberron calandar, moon phases, and plane positions plotted out. http://wizards.com/default.asp?x=dnd/ebwe/20041129a It takes some clicking, but you can fins out if it is possible or not.
mefron 10-12-05, 12:37 PM	I've already done all the calculations. Here is a message I posted on my campaign's site: As another point of interest, the next time all the moons will be full at the same time is on 6-28-5305 and this event should last about three days. I'm beginning to see a pattern. It looks like 6-28 is a special day because many lunar events happen on this day. Actually since year 0 the first ever 12 full moon event will be on 6-28-5305. What a special day that will be. As for when there will be all new moons, I have searched from 0YK upto 100,000 YK and have found no date in which all the moons are new. In fact at most I found only seven new moons (and in 100,000 years only 52 such days occur).
slainethehornedgod 10-12-05, 12:59 PM	Actually since year 0 the first ever 12 full moon event will be on 6-28-5305. Wouldn't it make sense that all new moons would be directly in the middle of the full moon pattern? So sometime in 2652?
mefron 10-12-05, 01:09 PM	Wouldn't it make sense that all new moons would be directly in the middle of the full moon pattern? So sometime in 2652? No, not nescessarily. Feel free to look for yourself but such a day does not exist. Besides you would want the middle of times when the moons were full. The moons were not all full in year 0 (or 1). You would have to use the last time they were full as your starting point. I expenaded my search to upto 1,000,000 YK and still I can only find at most seven simultaneous new moons.
slainethehornedgod 10-12-05, 01:34 PM	Oh, I looked at the luner cycles a bit more closely and it appears that not all the moons are on a 28 day cycle. For example, Therendor is full for 4 days every 42 days. The moons Olarune, Eyre, Vult, Zarantyr, Aryth, Dravago, Lharvion and Barrakas also appear to not be monthly and I'd be willing to bet they are all on slightly different cycles. I hadn't realized that. With that in mind I would think the chance that all the moons would naturally come into the same phase at the same time would be pretty remote. If non-existant. Of course as a DM you could simply make it how you want. Or have a NPC use some kind of eldrich machine or magic ritual to do it.
mefron 10-12-05, 01:38 PM	I've proven it mathematically (to myself), it is impossible for all the moons to be new at the same time. The main reason for this is that all the moons have periods which are perfect and are multiples of seven (28, 35, 43, 49, 56, 63, 70, 77, 84, 91, 98, and 105). When doing the math you end up with something like: 28 * K1 - 35 * K2 = 3.5 where K1 and K2 are integers. Obviously there is no solution for K1 and K2.
davethebrave371 10-12-05, 08:53 PM	I've proven it mathematically (to myself), it is impossible for all the moons to be new at the same time. The main reason for this is that all the moons have periods which are perfect and are multiples of seven (28, 35, 43, 49, 56, 63, 70, 77, 84, 91, 98, and 105). When doing the math you end up with something like: 28 * K1 - 35 * K2 = 3.5 where K1 and K2 are integers. Obviously there is no solution for K1 and K2. For my own curiosity, and because I'm horrible at math, could you answer me this question, please? When is the date where the most moons are new between the years 863-885, and how many moons is that?
mefron 10-13-05, 10:09 AM	For my own curiosity, and because I'm horrible at math, could you answer me this question, please? When is the date where the most moons are new between the years 863-885, and how many moons is that? There are five days where five of the moons are new in the period you asked about: 865 YK: Vult 16: Nymm Rhaan Eyre Zarantyr Barrakas Vult 18-19: Sypheros Rhaan Eyre Zarantyr Barrakas 869 YK: Dravago 25-26: Sypheros Olarune Zarantyr Lharvion Barrakas Dravago in 869 is a very dark month and if that's what you're looking for than that's your best choice.
davethebrave371 10-13-05, 09:30 PM	There are five days where five of the moons are new in the period you asked about: 865 YK: Vult 16: Nymm Rhaan Eyre Zarantyr Barrakas Vult 18-19: Sypheros Rhaan Eyre Zarantyr Barrakas 869 YK: Dravago 25-26: Sypheros Olarune Zarantyr Lharvion Barrakas Dravago in 869 is a very dark month and if that's what you're looking for than that's your best choice. Thank you very much! One of the characters in my group wanted his birthday on a moonless or mostly moonless night, and this works great. As his DM, I like to be able to seem all-knowing about some things, but I just couldn't find it on the calendar! Thanks again!
Streamweaver 10-13-05, 10:16 PM	Having Mefron as a player in my game I'm lucky to have his math skills available for such questions as well. I keep prodding him for some more details and sometime I think we intend to put up some kind of expanded version of an Eberron Lunar utility on our campaign site. Then if we did everything we wanted and even planned to do, we'd be a game publishing house in our own right. Hope our desire always outpaces our time and all but so many good things, so little time.
mefron 10-14-05, 12:32 PM	Here are the moons, and the number of days each spends in a particular phase. Here's the key to the phases: N New XC Waxing Crescent FQ First Quarter XG Waxing Gibbous F Full WG Waning Gibbous LQ Last Quarter WC Waning Crescent Moon Period N XC FQ XG F WG LQ WC Zarantyr 77 8.25 11 8.25 11 8.25 11 8.25 11 Olarune 56 6 8 6 8 6 8 6 8 Therendor 42 4.5 6 4.5 6 4.5 6 4.5 6 Eyre 63 6.75 9 6.75 9 6.75 9 6.75 9 Dravago 91 9.75 13 9.75 13 9.75 13 9.75 13 Nymm 28 3 4 3 4 3 4 3 4 Lharvion 98 10.5 14 10.5 14 10.5 14 10.5 14 Barrakas 105 11.25 15 11.25 15 11.25 15 11.25 15 Rhaan 49 5.25 7 5.25 7 5.25 7 5.25 7 Sypheros 35 3.75 5 3.75 5 3.75 5 3.75 5 Aryth 84 9 12 9 12 9 12 9 12 Vult 70 7.5 10 7.5 10 7.5 10 7.5 10 Forgive the formatting. BBCode doesn't allow tables or pre-formatted sections.
davethebrave371 10-14-05, 01:34 PM	Here are the moons, and the number of days each spends in a particular phase. Here's the key to the phases: N New XC Waxing Crescent FQ First Quarter XG Waxing Gibbous F Full WG Waning Gibbous LQ Last Quarter WC Waning Crescent Moon Period N XC FQ XG F WG LQ WC Zarantyr 77 8.25 11 8.25 11 8.25 11 8.25 11 Olarune 56 6 8 6 8 6 8 6 8 Therendor 42 4.5 6 4.5 6 4.5 6 4.5 6 Eyre 63 6.75 9 6.75 9 6.75 9 6.75 9 Dravago 91 9.75 13 9.75 13 9.75 13 9.75 13 Nymm 28 3 4 3 4 3 4 3 4 Lharvion 98 10.5 14 10.5 14 10.5 14 10.5 14 Barrakas 105 11.25 15 11.25 15 11.25 15 11.25 15 Rhaan 49 5.25 7 5.25 7 5.25 7 5.25 7 Sypheros 35 3.75 5 3.75 5 3.75 5 3.75 5 Aryth 84 9 12 9 12 9 12 9 12 Vult 70 7.5 10 7.5 10 7.5 10 7.5 10 Forgive the formatting. BBCode doesn't allow tables or pre-formatted sections. You sir, are a gem for any gaming group to place in it's crown. :bow:
mefron 10-14-05, 01:56 PM	Here is the revised chart. I engineered it to perfectly match the Eberron calendar posted online although careful examinination of this data will reveal strange lunar behavior. The numbers in the columns represent the day of that moon's cycle it will become the given phase. For example Zarantyr is new on days 1 through 7 of its phase and full on days 27 through 39 of its phase. The seed number is the day in phase on 1/1/998. Other seed values can easily be computed for any other day. To use this chart just keep track of twelve numbers (one for each moon) incrementing them (by one) for each game day. Set the numbers back to 1 whenever you exceed that moon's period. Refer to this chart to translate those numbers into phases. Moon Period Seed N XC FQ XG F WG LQ WC N Zarantyr 77 16 1 8 20 27 40 47 59 66 78 Olarune 56 34 1 6 14 19 31 36 44 49 57 Therendor 42 25 1 5 11 15 23 27 33 37 43 Eyre 63 14 1 7 17 23 32 38 48 54 64 Dravago 91 87 1 9 23 31 48 56 70 78 92 Nymm 28 16 1 4 8 11 15 18 22 25 29 Lharvion 98 96 1 10 26 35 49 58 74 83 99 Barrakas 105 61 1 10 26 35 56 65 81 90 106 Rhaan 49 19 1 5 13 17 25 30 38 42 50 Sypheros 35 19 1 4 10 13 17 21 27 30 36 Aryth 84 45 1 9 23 31 41 49 63 71 85 Vult 70 38 1 7 19 25 34 41 53 59 71 A more realistic chart would look like this (the same rules and seed numbers apply): Moon Period N XC FQ XG F WG LQ WC Zarantyr 77 1 9 20 28 39 47 58 67 78 Olarune 56 1 7 15 21 29 35 43 49 57 Therendor 42 1 5 11 16 22 26 32 37 43 Eyre 63 1 7 16 23 32 39 48 55 64 Dravago 91 1 10 23 33 46 56 69 79 92 Nymm 28 1 4 8 11 15 18 22 25 29 Lharvion 98 1 11 25 36 50 60 74 85 99 Barrakas 105 1 12 27 38 53 64 79 91 106 Rhaan 49 1 6 13 18 25 30 37 43 50 Sypheros 35 1 4 9 13 18 22 27 31 36 Aryth 84 1 10 22 31 43 52 64 73 85 Vult 70 1 8 18 26 36 43 53 61 71 Use whichever set you want.
davethebrave371 10-14-05, 02:22 PM	Here is the revised chart. I engineered it to perfectly match the Eberron calendar posted online although careful examinination of this data will reveal strange lunar behavior. The numbers in the columns represent the day of that moon's cycle it will become the given phase. For example Zarantyr is new on days 1 through 7 of its phase and full on days 27 through 39 of its phase. The seed number is the day in phase on 1/1/998. Other seed values can easily be computed for any other day. To use this chart just keep track of twelve numbers (one for each moon) incrementing them (by one) for each game day. Set the numbers back to 1 whenever you exceed that moon's period. Refer to this chart to translate those numbers into phases. Moon Period Seed N XC FQ XG F WG LQ WC N Zarantyr 77 16 1 8 20 27 40 47 59 66 78 Olarune 56 34 1 6 14 19 31 36 44 49 57 Therendor 42 25 1 5 11 15 23 27 33 37 43 Eyre 63 14 1 7 17 23 32 38 48 54 64 Dravago 91 87 1 9 23 31 48 56 70 78 92 Nymm 28 16 1 4 8 11 15 18 22 25 29 Lharvion 98 96 1 10 26 35 49 58 74 83 99 Barrakas 105 61 1 10 26 35 56 65 81 90 106 Rhaan 49 19 1 5 13 17 25 30 38 42 50 Sypheros 35 19 1 4 10 13 17 21 27 30 36 Aryth 84 45 1 9 23 31 41 49 63 71 85 Vult 70 38 1 7 19 25 34 41 53 59 71 A more realistic chart would look like this (the same rules and seed numbers apply): Moon Period N XC FQ XG F WG LQ WC Zarantyr 77 1 9 20 28 39 47 58 67 78 Olarune 56 1 7 15 21 29 35 43 49 57 Therendor 42 1 5 11 16 22 26 32 37 43 Eyre 63 1 7 16 23 32 39 48 55 64 Dravago 91 1 10 23 33 46 56 69 79 92 Nymm 28 1 4 8 11 15 18 22 25 29 Lharvion 98 1 11 25 36 50 60 74 85 99 Barrakas 105 1 12 27 38 53 64 79 91 106 Rhaan 49 1 6 13 18 25 30 37 43 50 Sypheros 35 1 4 9 13 18 22 27 31 36 Aryth 84 1 10 22 31 43 52 64 73 85 Vult 70 1 8 18 26 36 43 53 61 71 Use whichever set you want. Danke once again.