Playing with stardates

tng-stardate.rkt

@@ -0,0 +1,48 @@
+#lang racket/base
+
+(require racket/date)
+
+;; http://trekguide.com/Stardates.htm
+
+;; There are three ways to produce stardates, of which I'm choosing
+;; TNG's approach.
+
+
+;; http://en.memory-alpha.org/wiki/Stardate
+
+
+;; According to:
+;;
+;;     http://megiddo.wikidot.com/stardate
+;;
+;; we can compute the number of stardate units per day with this calculation.
+
+;; http://www.enotes.com/science/q-and-a/what-exact-number-days-one-year-179507
+(define days-per-year (/ 146097 400))
+
+(define stardate-units-per-year 1000)
+
+(define stardate-units-per-day (/ stardate-units-per-year
+                                  days-per-year))
+(define stardate-units-per-second
+  (/ stardate-units-per-day
+     (* 60 ;; 60 seconds per minutes
+        60 ;; 60 minutes per hour
+        24 ;; 24 hours per day
+        )))
+
+
+;; Season 1 was in the 41000's
+;; Season 2 was in the 42000's
+;; ...
+
+
+;; Season 1 Episode 1, Encounter at Farpoint was on April 13, 1987:
+;; http://en.memory-alpha.org/wiki/Encounter_at_Farpoint_(episode)
+;; Stardate 41153.7
+
+(define seconds-at-jan-1-1987 (find-seconds 0 0 0 1 1 1987 #f))
+(define seconds-at-april-13-1987 (find-seconds 0 0 0 13 4 1987 #f))
+
+(+ 41000 (* stardate-units-per-second (- seconds-at-april-13-1987
+                                         seconds-at-jan-1-1987)))