Starting the Elaion Facebook group, I hoped to have it be a medium for seekers to ask questions. Not 24 hours in, the first question has been asked, and I figured it would be good to share it with you. The question is: 'Is there a calendar that puts important dates onto a Julian-type calendar?', and the inferred question: 'How do I read it?' 

On Baring the Aegis, I have made available an overview of the monthly as well as yearly calendars. These are the festival dates I adhere to, and many were taken from the HMEPA calendar which can be found here. It is important to note that the ancient Hellenes started a new day at sundown the day before. Instead of starting a new day at midnight--or in the morning--like we do today, they started it at sundown of the previous day. This means that when looking at the HMEPA calendar, one ancient Hellenic day is stretched out over two modern days; from sundown on day one, to sundown on day two, when a new day began.

In the example above, the 12th ancient Hellenic day of the month (this month, in this case, Hekatombaion) stretches from (dusk on) the 20th of July, to (dusk on) the 21th of July. Next year, this date will be different, because the ancient Hellenic months were either twenty-nine or thirty days in length, since the moon orbits the earth in roughly 29.5 days. Hollow months had twenty-nine days, full months had thirty. The ancient Hellenes chose not to alternate the hollow and full months according to a set schedule ("Hekatombaion is a hollow month"), but instead, the duration of each month was declared just before month's end. The thirtieth day was always included; in a hollow month, the twenty-ninth day was left off of the calendar

A full lunar year is 354 days long. Because the earth rotates around the sun in roughly 365 days, an extra month was inserted into the calendar every few years--usually every third year. This month was usually a repeat of the previous month, most frequently Poseideon, but there are references to repeats of Hekatombaion, Metageitnion, Gamelion, and Anthesterion. It is unknown if the festivals which fell in this month were repeated as well, if other festivals were held, or if no festivals were celebrated at all. How long this month was, depended on the previous years. The ancient Hellenes had a tendency to repeat days to suit their needs, usually to postpone the arrival of a certain date. Assembly meetings, for example, were not held on festival days, so if the meeting was urgent, the previous day was repeated and the festival day postponed. A standard extra month would have been thirty-three days long, but it rarely was.

Long story short: if you know the ancient date of a festival, you can use the HMEPA calendar to find the appropriate modern day equivalent, but you need to do this every year, as the lunar nature of the ancient Hellenic calendar causes the dates to shift.

To make it a little easier, I also maintain a public Google Calendar which has all the festivals and monthly worship cycles I use for the Baring the Aegis calendar. Events stretch over two modern days, just like they would in ancient Hellas. Hopefully, this will help keep track of where we are in the ancient Hellenic month.

On the top left of this blog, right below the small bio is a small box with today's modern date, and the dates that would have fallen on this modern date if the ancient Hellenic calendar was still used. In the case of the example on the left, 'Middle First' is the eleventh day in the Hellenic month Hekatombaion, and this day started on July 19, at sundown. It lasts until sundown on the 20th of July, and then 'Middle Second', or the twelfth day of the Hellenic month Hekatombaion, starts. This lasts until sundown on July 21.

Hopefully, this will help you keep track of the festival days, and demystify the HMEPA calendar.