All you need is to know the current phase, a time-synced clock (most modern OSes do that) and a chart of when the phases happen relative to new moon. Code: +00:00 New Moon Blood River +08:45 Waxing Crescent Solace Bridge +17:30 First Quarter Highvale +26:15 Waxing Gibbous Brookside +35:00 Full Moon Owl's Head +43:45 Waning Gibbous Westend +52:30 Third Quarter Brittany Graveyard +61:15 Waning Crescent Etceter +70:00 The weird trick is that because the entire lunar cycle is a multiple of ten minutes, the seconds and ones of minutes will always be the same!* So if the current phase is Full Moon, and the current time is :48:00 into the hour, that means the current phase started at :45:00 into the hour, and the next phase will be at :53:45 into the hour, so the next phase (to Westend) happens in just over five minutes, and the next next one (to Brittany Graveyard) just under 9 minutes after that at :02:30. So print the chart and tape it to your monitor. *Note that this chart only works for full-hour time zones. If you live in a half-hour time zone, you will need to make a different table.