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# Day Numbers

After the invention of the computer it became important to number days by individual numbers. Astronomers use Julian Day Numbers. This website uses AA Numbers. Both show up in all date reports. What are they, how do they count?

There are many places where days are best known by a simple counting number. This is awkward for people since running math on very large numbers is not particularly easy, but since the invention of the computer this is not a problem.

## Julian Day Numbers

These numbers assign day numbers to individual days. For example, consider the following date report for today.

Today
Fri13004/4/24 AA24 May 2013 NS11 May 2766 AUCAAN: 4743594
3504/4/24 FE 11 May 2013 OS11 May 2013 ADJDN: 2456437

The field labeled JD: is the Julian Day number for today.

This day is defined as start at Noon, GMT and running through Noon the next day. This day definition is is NOT considered in the various reports because the current hour is not considered in the computations. If it was it would only confuse the charts since it would not reliably correlate with the other fields.

These numbers have an epoch at JD number 0. The following is the report:

Julian Day Number 0, the Julian Epoch
Mon6270/9/17 AA24 Nov -4713 NS19 Sep 4789 BAUCAAN: 2287157
-3230/9/17 FE 1 Jan -4713 OS19 Sep 5542 BCJDN: 0

January 1, -4713 OS is the defined starting epoch, day 0, on the JDN system, in agreement with other online JDN number calculators. Auditing this aspect of the Auditable Date Report.

## AA Numbers

The Julian epoch is not old enough for the purposes of computing Biblical dates while keeping the Julian day number positive.

To provide a similar day counting system this website uses "AA Numbers." This stands for "After Adam Numbers" which start with day number 1 assigned to 1/1/1 AA. The following report shows the AA Number epoch:

AA Number Epoch
Thu1/1/1 AA17 Nov -10975 NS7 Apr 12312 BAUCAAN: 1
-9499/1/1 FE 9 Feb -10975 OS7 Apr 13065 BCJDN: -2287156

Technically speaking these AANumber days align with the Bible Calendar days. By assigning an Epoch here, all days since the first day of the first year of Adam are numbered with a positive number. This is handy for human calculations and audit purposes across the time line and throughout the charts.

## Zero

Of course both day number counting systems have a day zero allowing days to be counted back past the epoch. The negative Julian Day number for the AA Number epoch can be seen in the previous report.

## Dynamic Range

Day numbers on this system are allowed in the range -2,000,000,000 <= DayNumber <= 2,000,000,000. This is sufficient for most uses.

The following report shows the first and last days using this day range.

First and Last Reliable days
First Day
Fri-5482456/12/10 AA11 Nov -5486789 NS15 Oct 6591260 BAUCAAN: -2000000000
-5491956/12/10 FE 13 Jul -5486676 OS15 Oct 6592013 BCJDN: -2002287157
Last Day
Mon5482457/3/20 AA21 Nov 5464839 NS6 Sep 5465480 AUCAAN: 2000000000
5472957/3/20 FE 6 Sep 5464727 OS6 Sep 5464727 ADJDN: 1997712843