No. 1 - 145_4539_r1.jpg
Upper dial face, facing south.
An equatorial sundial is actually a reduced model of the Earth, similar to a globe with its upper and lower halves removed: the dial plate represents the plane of the Earth's Equator; the gnomon represents the Earth's axis of rotation.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:34:04 |
| Exposure Time: | 1/8 sec |
| F-Number: | f/7.1 |
| Lens Aperture: | f/7.1 |
| Exposure Bias: | 2/3 |
| Flash: | No Flash |
| Focal Length: | 10.19 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1644 |
| Image Height: | 2226 |
No. 2 - 145_4529_r1.jpg
Lower dial face, facing north.
The gnomon is the part of a sundial that casts the shadow used to tell time. For equatorial sundials, the gnomon is a pole (or rod) of varying thickness. The gnomon shadow falls on the upper dial face from the MAR Equinox to SEP Equinox; the gnomon shadow falls on the lower dial face from the SEP Equinox to MAR Equinox.
The apparent discrepancy between solar time and standard time is caused
by: 1) the Equation of
Time (EoT);
2) the difference
in longitude between the location of the sundial and the Standard Time
Meridian (STM) for the Mountain Time Zone (MTZ STM = 105°W); and 3) Daylight Saving
Time.
- Date/Time Original: 2003:11:08 / 16:29:36
(~4:30 p.m. MST) - Gnomon shadow = ~4:45 to 4:47 Local Apparent Time (L.A.T.)
- Equation of Time (EoT) = -16.3m
- ~4:46 L.A.T. - 16.3m EoT = ~4:30 p.m. MST
(same time indicated by photo metadata)
Note: In this case, the difference in longitude between the sundial location and MTZ STM is negligible.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:29:36 |
| Exposure Time: | 1/50 sec |
| F-Number: | f/3.5 |
| Lens Aperture: | f/3.5 |
| Exposure Bias: | 0/3 |
| Flash: | No Flash |
| Focal Length: | 20.69 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1637 |
| Image Height: | 2106 |
No. 3 - 145_4567_r1.jpg
Close-up side view, facing west.
The gnomon of a properly oriented equatorial sundial points toward the Celestial North Pole.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:49:37 |
| Exposure Time: | 1/50 sec |
| F-Number: | f/4.0 |
| Lens Aperture: | f/4.0 |
| Exposure Bias: | -2/3 |
| Flash: | No Flash |
| Focal Length: | 28.81 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1704 |
| Image Height: | 2272 |
No. 4 - 145_4550_r1.jpg
Side view, facing east.
The gnomon should be parallel to the Earth's axis, inclined at an angle equal to the latitude of the observer. The dial plate should be parallel to the plane of the Earth's Equator (perpendicular to the gnomon), inclined at an angle equal to the complement of the observer's latitude. This angle is also known as the colatitude. The Brighton, CO sundial gnomon angle of inclination = ~40 degrees; dial plate angle of inclination = ~50 degrees.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:42:02 |
| Exposure Time: | 1/80 sec |
| F-Number: | f/2.5 |
| Lens Aperture: | f/2.5 |
| Exposure Bias: | -2/3 |
| Flash: | No Flash |
| Focal Length: | 17.59 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1625 |
| Image Height: | 2196 |
No. 5 - 145_4545_r1.jpg
Garmin GPSmap 76S.
Wrist strap of GPS receiver looped around sundial gnomon, upper dial face. Note: Location inscribed on sundial is nearly identical to location displayed by GPS receiver (see photo No. 6).
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:38:08 |
| Exposure Time: | 1/6 sec |
| F-Number: | f/6.3 |
| Lens Aperture: | f/6.3 |
| Exposure Bias: | 2/3 |
| Flash: | No Flash |
| Focal Length: | 9.09 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1557 |
| Image Height: | 2267 |
No. 6 - 145_4548_r1.jpg
Close-up, GPS receiver.
Close-up, Garmin GPSmap 76S GPS receiver showing exact location of sundial (+/- ~15 ft).
- Elevation: 5030 ft
- Accuracy: 14.8 ft
- Date/Time: 08 NOV 03 / 16:38:57 MST
- Latitude: N 39.92538°
- Longitude: W104.87789°
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:39:13 |
| Exposure Time: | 1/8 sec |
| F-Number: | f/6.3 |
| Lens Aperture: | f/6.3 |
| Exposure Bias: | 2/3 |
| Flash: | No Flash |
| Focal Length: | 20.69 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1666 |
| Image Height: | 2244 |
No. 7 - 145_4576_r1.jpg
Upper dial face.
Upper dial face as viewed from the north (facing south). The upper dial face represents the Northern Hemisphere; the lower dial face represents the Southern Hemisphere.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:54:14 |
| Exposure Time: | 1/10 sec |
| F-Number: | f/2.5 |
| Lens Aperture: | f/2.5 |
| Exposure Bias: | 2/3 |
| Flash: | No Flash |
| Focal Length: | 17.59 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1563 |
| Image Height: | 2115 |
No. 8 - 145_4582.jpg
Close-up, upper dial face inscription.
Close-up of text, upper dial face (northern side of sundial). Transcript of inscription:
read this side
Tempus Fugit - Time Flies
This equatorial Sun dial was erected for
your enjoyment on November 21, 2000.
Funds provided by Adams County Cultural Council,
Adams County Historical Society,
and Scientific and Cultural Facilities District.
Brighton, Colorado
Longitude W104.8, latitude N40.0
7 hrs. west of Grenwich [sic] England
Note: The Prime Meridian is located in Greenwich, England (pronounced, 'gre-nich').
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Sensing Method: | One-Chip Color Area |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:57:59 |
| Exposure Time: | 1 sec |
| F-Number: | f/7.1 |
| Lens Aperture: | f/7.1 |
| Exposure Bias: | 2/3 |
| Maximum Lens Aperture: | f/2.2 |
| Metering Mode: | Pattern |
| Flash: | No Flash |
| Focal Length: | 9.09 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 2272 |
| Image Height: | 1704 |
No. 9 - 145_4569_r1.jpg
Tempus Fugit: Time Flies!
Lower dial face (southern side of sundial). Transcript of inscription:
read this side
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:50:50 |
| Exposure Time: | 1/20 sec |
| F-Number: | f/3.0 |
| Lens Aperture: | f/3.0 |
| Exposure Bias: | -2/3 |
| Flash: | No Flash |
| Focal Length: | 28.81 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1554 |
| Image Height: | 1896 |
No. 10 - 145_4572_r1.jpg
Lower dial face, facing northeast.
View from the southwest (facing northeast).
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:52:11 |
| Exposure Time: | 1/15 sec |
| F-Number: | f/3.0 |
| Lens Aperture: | f/3.0 |
| Exposure Bias: | -2/3 |
| Flash: | No Flash |
| Focal Length: | 28.81 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 1505 |
| Image Height: | 2022 |
No. 11 - 145_4540.jpg
Graph, Equation of Time (MAR-SEP).
Graph, Equation of Time (EoT) used to correct solar time for standard time. Transcript of inscription:
left edge of shadow in p.m. Add or subtract number of
minutes shown on chart for current date. The results
will be standard watch time for this area. Subtract [sic] one hour
for Daylight Savings [sic] Time.
Note: Add one hour for Daylight Saving Time.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Sensing Method: | One-Chip Color Area |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:35:17 |
| Exposure Time: | 1/8 sec |
| F-Number: | f/7.1 |
| Lens Aperture: | f/7.1 |
| Exposure Bias: | 0/3 |
| Maximum Lens Aperture: | f/2.2 |
| Metering Mode: | Pattern |
| Flash: | No Flash |
| Focal Length: | 10.19 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 2106 |
| Image Height: | 1683 |
No. 12 - 145_4577.jpg
Graph, Equation of Time (SEP-MAR).
Graph, Equation of Time (EoT) used to correct solar time for standard time. Transcript of inscription:
right edge of shadow in p.m. Add or subtract number of
minutes shown on chart for current date. The results
will be standard watch time for this area. Subtract [sic] one hour
for Daylight Savings [sic] Time.
Note: Add one hour for Daylight Saving Time.
| Equipment Make: | Canon |
| Camera Model: | Canon PowerShot G3 |
| Camera Software: | Adobe Photoshop CS Windows |
| Sensing Method: | One-Chip Color Area |
| Image Orientation: | Top, Left-Hand |
| Horizontal Resolution: | 180 dpi |
| Vertical Resolution: | 180 dpi |
| Image Created: | 2003:11:08 16:56:18 |
| Exposure Time: | 1 sec |
| F-Number: | f/7.1 |
| Lens Aperture: | f/7.1 |
| Exposure Bias: | 0/3 |
| Maximum Lens Aperture: | f/2.0 |
| Metering Mode: | Pattern |
| Flash: | No Flash |
| Focal Length: | 7.19 mm |
| Color Space Information: | Uncalibrated |
| Image Width: | 2081 |
| Image Height: | 1549 |