Seth_Zaw wrote:

What if someone did this:

when green flag clicked
ask [Enter a holiday and I'll calculate the month.] and wait
say (date [month v] of (answer) :: sensing)

Today is February 30th :: boolean operator

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

((((days since 2000) - (6)) mod (29.53059)) / (29.53059))

fdreerf wrote:

I made one.

((((days since 2000) - (6)) mod (29.53059)) / (29.53059))

This gives the lunar phase as a percentage, where 0 is a new moon, 0.5 is a full moon and it cycles forever.
I subtracted 6 because that's the closest new moon to January 1st was on the 6th.

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

chrdagos wrote:

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

nope.
the moon is drifting away from the earth, which means the moon's orbit will take longer and longer.

chrdagos wrote:

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

nope.
the moon is drifting away from the earth, which means the moon's orbit will take longer and longer.

scramaso wrote:

So, new moon is 0, full is 0.5 and 1 is new too?

fdreerf wrote:

chrdagos wrote:

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

nope.
the moon is drifting away from the earth, which means the moon's orbit will take longer and longer.

Fun fact: the moon drifts at 3.8 cm on average per year. In 500 years, it would've moved only 19 meters. Spoiler alert: everyone alive today will be dead.

fdreerf wrote:

the moon drifts at 3.8 cm on average per year

scramaso wrote:

fdreerf wrote:

chrdagos wrote:

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

nope.
the moon is drifting away from the earth, which means the moon's orbit will take longer and longer.

Fun fact: the moon drifts at 3.8 cm on average per year. In 500 years, it would've moved only 19 meters. Spoiler alert: everyone alive today will be dead.

exactly

private static DateTime Easter(int year) {
    int a = year%19;
    int b = year/100;
    int c = (b - (b/4) - ((8*b + 13)/25) + (19*a) + 15)%30;
    int d = c - (c/28)*(1 - (c/28)*(29/(c + 1))*((21 - a)/11));
    int e = d - ((year + (year/4) + d + 2 - b + (b/4))%7);
    int month = 3 + ((e + 40)/44);
    int day = e + 28 - (31*(month/4));
    return new DateTime(year, month , day);
}

imfh wrote:

scramaso wrote:

fdreerf wrote:

chrdagos wrote:

fdreerf wrote:

Wait, couldn't you create a workaround with some magic math formula, using 29.53059 (a synodic month) to get the lunar phases forever?

nope.
the moon is drifting away from the earth, which means the moon's orbit will take longer and longer.

Fun fact: the moon drifts at 3.8 cm on average per year. In 500 years, it would've moved only 19 meters. Spoiler alert: everyone alive today will be dead.

exactly

So, you could use that to simplify the code below to and find Easter? If so, I am surprised I haven’t seen a formula which has already uses it. I don’t think that magic number is accurate enough to get Easter reliably.

private static DateTime Easter(int year) {
    int a = year%19;
    int b = year/100;
    int c = (b - (b/4) - ((8*b + 13)/25) + (19*a) + 15)%30;
    int d = c - (c/28)*(1 - (c/28)*(29/(c + 1))*((21 - a)/11));
    int e = d - ((year + (year/4) + d + 2 - b + (b/4))%7);
    int month = 3 + ((e + 40)/44);
    int day = e + 28 - (31*(month/4));
    return new DateTime(year, month , day);
}

Source

fdreerf wrote:

So, all we need to do is calculate the first Sunday after the first full moon on or after 21 March. (Thanks Wikipedia!) I can't say I can use the code imfh gave us because I can't understand C# and it looks like even those who do are confused, so I'm making my own thing. As of now, the hardest part seems to be when to detect the day of the week.

imfh wrote:

private static DateTime Easter(int year) {
    int a = year%19;
    int b = year/100;
    int c = (b - (b/4) - ((8*b + 13)/25) + (19*a) + 15)%30;
    int d = c - (c/28)*(1 - (c/28)*(29/(c + 1))*((21 - a)/11));
    int e = d - ((year + (year/4) + d + 2 - b + (b/4))%7);
    int month = 3 + ((e + 40)/44);
    int day = e + 28 - (31*(month/4));
    return new DateTime(year, month , day);
}

imfh wrote:

fdreerf wrote:

So, all we need to do is calculate the first Sunday after the first full moon on or after 21 March. (Thanks Wikipedia!) I can't say I can use the code imfh gave us because I can't understand C# and it looks like even those who do are confused, so I'm making my own thing. As of now, the hardest part seems to be when to detect the day of the week.

You can detect the day of week with the current [ v] block.

fdreerf wrote:

imfh wrote:

fdreerf wrote:

So, all we need to do is calculate the first Sunday after the first full moon on or after 21 March. (Thanks Wikipedia!) I can't say I can use the code imfh gave us because I can't understand C# and it looks like even those who do are confused, so I'm making my own thing. As of now, the hardest part seems to be when to detect the day of the week.

You can detect the day of week with the current [ v] block.

Yes, but what I'm doing spits out the the nth day of the year Easter falls on. It's hard to figure out the day of the week with only “99” and “2020” to work with.
Also, I tried the C# way and it didn't work.