An ANCHOR is a mnemonic for calculating the day of the week for any
date in history, at least since the advent of the Gregorian
calendar, which occurred in the American colonies on September 2,
1752.
For example, the ANCHOR for the year 2008 is FRIDAY. That means
that all of the following easy-to-remember dates in 2008 are
Fridays:
4/4, 6/6, 8/8, 10/10, 12/12
5/9, 7/11, 9/5, 11/7 (I work 9 to 5 at the 7-11)
1/4 in leap years, 1/3 in non-leap years (1/4 every four years,
1/3 the other three)
And finally, March 0 (in other words, the last day of
February, which in 2008 is 2/29, a leap day, the date this cache
was hidden).
Days of the week for other dates can be found by working off the
ANCHOR for that month.
Now, how do we find the anchor for other years?
For our purposes, let's just use the facts that
- the ANCHOR for a year repeats every 28 years
- if you move ahead into a non-leap year, the ANCHOR moves ahead
one day
- if you move ahead into a leap year, the ANCHOR moves ahead two
days.
Here is a table for you to use.
| + |
2000 |
1700 |
1800 |
1900 |
| 00 |
TU |
SU |
FR |
WE |
| 85 57 29 01 |
WE |
MO |
SA |
TH |
| 86 58 30 02 |
TH |
TU |
SU |
FR |
| 87 59 31 03 |
FR |
WE |
MO |
SA |
| 88 60 32 04 |
SU |
FR |
WE |
MO |
| 89 61 33 05 |
MO |
SA |
TH |
TU |
| 90 62 34 06 |
TU |
SU |
FR |
WE |
| 91 63 35 07 |
WE |
MO |
SA |
TH |
| 92 64 36 08 |
FR |
WE |
MO |
SA |
| 93 65 37 09 |
SA |
TH |
TU |
SU |
| 94 66 38 10 |
SU |
FR |
WE |
MO |
| 95 67 39 11 |
MO |
SA |
TH |
TU |
| 96 68 40 12 |
WE |
MO |
SA |
TH |
| 97 69 41 13 |
TH |
TU |
SU |
FR |
| 98 70 42 14 |
FR |
WE |
MO |
SA |
| 99 71 43 15 |
SA |
TH |
TU |
SU |
| 72 44 16 |
MO |
SA |
TH |
TU |
| 73 45 17 |
TU |
SU |
FR |
WE |
| 74 46 18 |
WE |
MO |
SA |
TH |
| 75 47 19 |
TH |
TU |
SU |
FR |
| 76 48 20 |
SA |
TH |
TU |
SU |
| 77 49 21 |
SU |
FR |
WE |
MO |
| 78 50 22 |
MO |
SA |
TH |
TU |
| 79 51 23 |
TU |
SU |
FR |
WE |
| 80 52 24 |
TH |
TU |
SU |
FR |
| 81 53 25 |
FR |
WE |
MO |
SA |
| 82 54 26 |
SA |
TH |
TU |
SU |
| 83 55 27 |
SU |
FR |
WE |
MO |
| 84 56 28 |
TU |
SU |
FR |
WE |
Launched:
- A: USS Minneapolis (CA-36)
- B: USS Essex (War of 1812 sailing frigate)
- C: USS Milwaukee (CL-5)
- D: USS Saint Paul (former passenger liner)
- E: SS Gopher State (T-ACS-4)
- F: USS Saint Paul (CA-73)
- G: USS Wisconsin (BB-64)
- H: USS Columbus (ship of the line)
- I: USS Fort Snelling (LSD-30)
- J: USS Duluth (CL-87)
- K: USS Minneapolis-Saint Paul (SSN-708)
- L: USS Monitor (Civil war ironclad)
1=Sunday
N44 54.(A+B)(C+D)(E+F)
W93 03.(G+H)(I+J)(K+L)
ignore tens digit
You can check your answers for this puzzle on
Geochecker.com.