What does a yellow porch light mean? Yellow porch lights are bug lights. By bug light I mean they are not supposed to attract bugs as bad as regular light bulbs.
GPS Week Number Rollover. The GPS Week Number count began at approximately midnight on the evening of 05 January 1980 / morning of 06 January 1980. Since that time, the count has been incremented by 1 each week, and broadcast as part of the GPS message. The GPS Week Number field is modulo 1024. This means that at the completion of week 1023, the GPS week number rolled over to 0 on midnight GPS Time of the evening of 21 August 1999 / morning of 22 August 1999. Note that this corresponded to 23:59:47 UTC on 21 August 1999.
In the Gregorian calendar, we have seven days of the week and, depending on the month, anywhere from 28 to 31 days. The Tzolk'in calendar is made up of a set of 20 day names, symbolized by images called glyphs, and 13 numerals called tones. The days are numbered one through 13, and the names are also given in sequence.