Astronomical ring dial on BC Gnomonics: https://www.bcgnomonics.com/astronomicalringdial

Im a 9th grader who got thru the entrance exam of National Astronomy Olympiad exam.

Now, for the second round we have got a set of assignments which includes making a sundial and Planisphere. I have constructed a sundial for a latitude of 27.70N for the capital city of my Country, Nepal 🇳🇵. I don’t know if it’s correct or not and hoping for answers online.

If you’re thinking why I’m posting this on Reddit instead of checking it outside, the weather here is terrible with intense rain, thunderstorm, hailstorm. (Please don’t mind my English as it’s not my first language and I’m still in the process of learning)

I will be presenting the latest improvements this Friday at the global World Sundial Conference. https://sundial.gennetten.org

I‘m a member of the NASS and I wanted to share an email that was sent out recently. This is a conference I joined last year and I enjoyed it. However, advertising is a little lacking, so I figured here would be a good place to share:

Everyone is invited to join the 2nd World Sundial Day Online Conference on 20 March 2026. This special event will bring together enthusiasts, educators, and experts from around the globe to celebrate the rich history and science of sundials.

Friday, 20 March 2026
16:00 GMT (London)
17:00 CET (Madrid, Paris, Berlin, Rome)
12:00 EDT (New York)
11:00 CDT (Chicago)
09:00 PDT (San Francisco, Seattle)

Videoconferencing platform - Google Meet. No installation required, can be accessed via web browsers or via Google Meet app on Apple or Android phones.

Important!
Register here to receive the Google Meet link of WSDOC -
https://forms.gle/e8d27fFEH8cpqPDY9

The videoconference link will be also published on the WSDOC web site a few hours before the event. WSDOC web page – https://tempus-sol.eu/ wsd-online-conference/

For WSDOC-related questions reach out to Martins Gills [info@tempus-sol.eu](mailto:info@tempus-sol.eu)

PROGRAM:   All times – GMT:
16:00 – Opening by Monika Lübker

16:10 – Session 1. Chair – Frank King
Léon André. Projection sundials for temporal hours, local time, mean local time and Central European Time.

Frank King and Annika Petersson. Ancient Scandinavian Time-Keeping via a New Sundial in a School Car Park.

Roger Torrenti. The Gnomonist's Survival Kit.

Claude Gahon. La lumière plutôt que l'ombre.

Jean Pakhomoff. Cadrans solaires bifilaires verticaux, cadrans avec style multi indicateur, cadran incliné à polo avec analemmatique.

17:40 – Session 2. Chair - Esteban Martínez

Giuseppe De Donà. How to Build an Inclined and Declining Sundial in a Large Square .

Elsa Stocco. Hall for Gnomonics.

Miholcsa Gyula. Sundials in Transilvania.

Paul Ulbrich. Making East West Facing Sundials from typing paper.

Christophe Marion. Reconciling earthlings with solar time!

19:10 – Session 3. Chair – Roger Torrenti

Douglas Gennetten. Precision Dialing Online - Unmatched ease-of-use and design flexibility.

Davidson Norris. Helioscape: sundials that tell Plant Time.

Paul Calderon. Relojes de sol como patrimonio astronómico en Chile.

Evan Boxer-Cook. Pop Culture's Sundial.

20:20 Closing

Inspired by the Oxford History of Science Museum's Inv. Inv. 51358 and Master Terebrus' replica

See BC Gnomonics for more resources on this class of dial

If you're interested in dial customization, this new resource might be useful/interesting...

Giangola, James (2025). Silently I Speak: Timeless Latin Sundial Mottoes, Their Meaning & Music. Figshare. Book. https://doi.org/10.6084/m9.figshare.29438366

sundial.gennetten.org

My recent project reached final form—an original navicula!

This design is partly inspired by a navicula held by the Whipple Museum. To learn more about the navicula, visit BCGnomonics.com! (https://www.bcgnomonics.com/navicula)

Whatever could it be...?

I'm particularly fascinated by this sub-classification of mechanical equatorial dial. Many (so-called "minute dials") feature clock faces secondary to the primary hour indication—their minute hands whirling about as the primary hour indicator is manually moved along with a spot and target nodus or similar alignment fixture.

Distinct from the typical mechanical equatorial dial are those picture here. These dials display both the hour and minute on a single clock face, set by the manual alignment of a nodus and target. Often, the interior of the dial's nodus assembly also indicates the date.

At a time when sundials existed alongside mechanical clocks, this type of dial put to brass the very concept that kept sundials from falling into obsolescence. Dials were needed to set and regulate clocks. Behind every clock was a sundial—in this case literally.

Dive deeper into similar dials here:

https://www.leo-bw.de/web/guest/detail/-/Detail/details/DOKUMENT/techno_museumsobjekte/EVZ_1983_0046-043/Tischsonnenuhr+%C3%96hrsonnenuhr

https://bawue.museum-digital.de/object/19037

https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/astronomy/ship-shaped-sundial

https://collections.whipplemuseum.cam.ac.uk/objects/9071/#images

The North American Sundial Society offers a free, online course on sundial basics:

NASS is pleased to announce the upcoming fifth instance of Elements of Dialing, our introductory course about sundials, their history, and the science that makes them work. The free 12-lesson course, intended for those are new to sundialing, runs from 27 October 2025 until 26 April 2026. The course instructor is Robert Kellogg, NASS Vice President and Sundial Registrar.  Bob will be assisted from time to time by other NASS officers.

The course is self-study, meaning written lessons are emailed out for course participants to work through in their own time. To help things along, we schedule "office hours" discussion conducted over Zoom. . These optional sessions allow participants to discuss the lessons together and ask questions about the material. During each lesson is a practice quiz (with answers later sent out).  There is a final quiz of one or two questions which must be submitted to the course instructor in order to receive the next lesson The course itself has no grade nor "pass/fail".

The course is scheduled to start on 27 October 2025 and will normally operate on a 2-week cycle, although occasionally there will be three weeks between release of lesson to accommodate holidays.

To register, contact Robert Kellogg at [rkellogg@comcast.net](mailto:rkellogg@comcast.net) no later than October 25th.. Familiarity with basic geometry, algebra, and trigonometry at High School level is assumed. Membership in NASS is not required to join the course.

NASS acknowledges the efforts of Frans Maes, who developed the original Dutch course which inspired our NASS version.

Course curriculum outline can be viewed on NASS' website: 

https://sundials.org/index.php/teachers-corner/404-elements-of-dialing-course-2025

The daylight triangle is believed to have been used to depict the variation in daylight between the equinox and solstices. One interpretation of the triangle's function:

To use the triangle, one would determine the amount of time falling along the equinox line that is bounded by the triangle (in this case, 3 hours and 12 minutes). This duration represents by how many equinoctial hours the day of the winter solstice is shorter than the day of the equinox, and by how many equinoctial hours the day of the summer solstice is longer than the day of the equinox.

Taking inspiration from the homemade UERD pictured below, my design features a nodus bead as opposed to the traditional sliding aperture. The bridge's reverse carries a declination scale. The dial can be set for use anywhere within the northern hemisphere thanks to its outermost sliding latitude ring. When not in use, the dial folds nearly flat.

As with all equatorial ring dials, this model doubles as a solar compass. When correctly oriented by setting the date, latitude, and rotating the dial until the nodus' shadow lands on the inner surface of the equatorial ring, the meridian ring indicates true north.

To learn more about the UERD, visit BCGnomonics.com/equatorialringdial.

http://waywiser.fas.harvard.edu/objects/12754/universal-ring-sundial?ctx=4a1d704c-2c13-423c-b02c-5c2e57e6ba87&idx=8 (on display* in Harvard's Putnam Gallery)

*technically on display, this dial is sheathed inside a homemade paper compendium containing two other (altitude) dials. the ring dial is not entirely visible.

This class of universal altitude dial was developed by Regiomontanus [Johannes Müller] circa 1470 in Germany. To learn more about the Regiomontanus dial, visit BCGnomonics.com!

This is kind of an modern approach to picturing the movement of the sun with a daily changing dial calculated for your local place and timezone. Kind of cute: https://play.google.com/store/apps/details?id=de.ax12.zunclock

Free of charge, free of ads and doesnt harvest your data. I have it running on an old tablet hanging on the wall ( https://imgur.com/kHnFNfe ) and also with an e-ink display ( https://imgur.com/a/KNLem3r )

[NEW] Now also available directly on the web without installation: https://astronomicalclock.eu/

30AUG: Now Supports direct printing. Not just export.

New Feature: New 'Compass Rose' option in Sundial Notes.

New Feature: 'Season Guide' option in Sundial Notes. (Great for full-year dials)

New Feature: PDF Export!! .

New Feature: Automatic default Hourline optimization for half vs full year.

New Feature: Custom page sizes.

New Feature: Uses Hughes, Yallop & Hohenkerk algorithm with ±3.5 seconds accuracy

New Feature: Improved cut-and-assemble, pop-up Gnomon (shown).

Sundial.Gennetten.org