The Dialist's Companion is an MS-DOS program (compatible with all versions of Windows) that calculates a wide range of data elements of interest to dialists and others who are concerned with phenomena associated with solar time. These data elements are presented in a dynamic format, changing each second with the tick of the user's system clock. The user can define any latitude and longitude as the platform for his observations, and explore any time or date between 1 A.D. and 2999 A.D. The program further adapts to the user's preferences through the use of start up options and user defined configuration files which can be saved and retrieved.

The program provides three different screens which present the output in different formats. The screens can be switched at a keystroke, and consist of the Main Screen, the Clock Screen, and the Equation Chart.

The Main Screen contains tabular output of the various computed values. These values are described and discussed in the program's User's Guide, which is provided in both on-line and printable versions.

The Clock Screen displays two digital clocks which can be set individually to any of the seven times systems calculated by the program. The display is designed to show selected times with maximum visibility for field use. An alarm can be set to either clock or independently to local apparent noon.

The Equation Chart presents the Equation of Time and the sun's declination in a monthly format.

Click a screen to view: [[ Main Screen || Clock Screen || Equation Chart ]]

The program date and time can be manipulated in two ways, either by direct entry or by incremental changes from the keyboard. The program clock can also be paused, permitting examination of an instant. At any point, a keystroke will return the program to the system date and time.

Dates between 1 A.D and 2999 A.D. (inclusive) are permitted. Dates before Oct 15, 1582 are based on the Julian calendar; dates after October 4, 1582 are based on the modern Gregorian calendar.

The following is a list of the included data elements. All values can be viewed simultaneously. Dynamic elements are updated every second.

• Solar Ephemeris
  • Sunrise and Sunset
  • Altitude and Azimuth
  • Declination
  • Equation of Time
  • Zodiac

• Time Systems
  • Local Standard Time
  • Greenwich Mean Time
  • Dial Time
  • Sidereal Time
  • Julian Day Number
  • Babylonian and Italian Hours
  • Temporal Hours

• Factors affecting a specific sundial
  • Longitude Correction
  • Refraction Correction
  • Total Correction

• Other Useful Data
  • Solar Noon
  • Shadow

• Mottos
  • If all of the above isn't enough, the program also randomly displays a series of 23 appropriate sundial mottos.

The Dialist's Companion is written for DOS platforms and requires 336k of disk space and a VGA monitor. It runs well under Windows but Vista users have reported problems with the graphical Clock Screen.

The program was originally released as part of the North American Sundial Society's Digital Compendium as one of the many benefits of NASS membership. It is now being released to non-members as Shareware. The registration fee is $15 US, and may be sent to Fred Sawyer at the address above. (Please make checks payable to NASS.)

If you choose to join NASS, the registration fee may be applied to your first year's dues. Basic dues are $25, but there are options. See the Join NASS link at:

History of Releases

Version 1.1b   Released May 2003
               Updated authors' email addresses and NASS website URL.
               Converted DIALIST.DOC to plain text
               and renamed to DIALIST.TXT
               
Version 1.1    Released January 1997
               Fixed a bug which occurred only in latitudes south
               of the Equator, when the Refraction Correction option
               was selected.

Version 1.0    First Released September 1996 as a Digital Bonus to
               The NASS Compendium Vol. 3 Number 3.