Rev. Herbert A. Phinney described a system for describing Vatican postmarks without reproducing it graphically in Vatican Notes back in 1961.¹ The V.P.S. cancellation list uses a record layout much as Rev. Phinney described with a few modifications aided with the display of graphic images as modern-day computers allow. This system is primarily for circular postmarks such as the two pictured above. The outer and inner circles form the top and bottom spaces of the postmark, with some sort of a separator, which are usually stars. The space inside the inner circle is referred to as the “moon” having an upper, center, and lower spaces.

Non-circular postmarks are also included in the V.P.S. cancellation list using the same record fields as appropriate.

The V.P.S. Cancellation Record consists of the following fields:

• Year – four-digit year of the postmark
• PM Date – postmark date, format YYYY-MM-DD
• Cancel Type – postmark type, either “Special” or “Every-Day”
• Top Inscription – postmark inscription usually “Citta Del Vaticano” or something simular
• Separation – generally 5, 6, pointed 8 pointed stars, sometimes asterisks, or a Maltese cross
• Bottom Inscription – sometimes “Poste”, “Posta Aerea” or "Poste Vaticane"
• Upper Moon – usually numeric number thought to be the number of the postmark canceling device
• Center – postmark date format, sometimes with the hour
• Lower Moon – thought indicate where the cancel as applied (C – Central Post Office, F-philatelic usage)
• Diameter (of the circles) – measured in mm
• Image – the filename of jpg photo image of the postmark, stored in the V.P.S. postmark directory
• Cover – the jpg filename of the stamp cover, stored in the V.P.S. stamp cover directory
• Notes – a free text field for descriptive notes

References:
¹ Phinney, Rev. Herbert A. “Cancellation Research Project” Vatican Notes, Vol. X, No 3, Nov-Dec 1961, Pages 7-8 (click here)