Photo Descriptors - The Brookside Gardens Botanical Sundial ROW 1 No. 1 - BGMD_MVC-001F3.jpg Facing northeast. The Brookside Gardens Botanical Sundial (BGBS) is a classic horizontal sundial with a distinctive spin--some of its parts are made of plants and flowers! A horizontal sundial consists of a horizontal dial plate and polar-pointing gnomon. No. 2 - BGMD_MVC-003F.jpg Facing east. The gnomon is the part of a sundial that casts the shadow used to tell time. Typically, horizontal sundials have a triangle-shaped gnomon. The upper edge of the gnomon is known as the 'style.' (Note: The BGBS has two styles, since its gnomon is one foot wide.) The gnomon (or style) of a properly oriented horizontal sundial points toward the Celestial North Pole, inclined at an angle equal to the observer's latitude. The BGBS gnomon angle of inclination = ~39 degrees. No. 3 - BGMD_MVC-005F3.jpg Facing west. The dial face is 21 feet in diameter. The gnomon is 10 feet in length, 8.115 ft. in height, and 1 ft. in width. Elena Scire, Fairfax County Master Gardener, shown for vertical scale. Ms. Scire is 62.5 inches (158.75 cm) tall. The gnomon is made of a 3/8" plywood sheathing on top of a wooden frame of pressure-treated 2x2s. The curved part of the gnomon is made of Luan wood; the style is made of exterior-grade MDO plywood. The gnomon has louvers for ventilation (see lower-left and right corners of gnomon) and is painted with a faux marble finish. The gnomon is light-weight by design, bolted to an underground steel frame for ease of installation/removal. ROW 2 No. 4 - BGMD_MVC-002F.jpg The hour lines are made of two varieties of Alternantha, a low-growing plant. For each hour line, the plants are arranged in alternating segments of darker and lighter shades of green. No. 5 - BGMD_MVC-005F.jpg The darker-green plant is Alternantha 'Red Crinkle Leaf.' Common name: Joseph's Coat. Yellow plastic Arabic numerals are mounted on a plywood base (painted black) that is attached to a pedestal made of PVC pipe, buried in the soil so that it is not easily removed. No. 6 - BGMD_MVC-001F2.jpg The lighter-green plant is Alternantha 'Snow Queen.' Common name: Joseph's Coat. ROW 3 No. 7 - BGMD_MVC-002F3.jpg The shadow of the gnomon (or style), cast among the hour lines on the dial face, shows the time. Sun shadows fall in the opposite direction as the Sun, therefore morning times are located on the western side of the gnomon (right side with respect to the photo), afternoon times are on the eastern side. During the morning, time is told by reading the left edge of the gnomon shadow; the right edge is used during the afternoon. No. 8 - BGMD_MVC-003F3.jpg The BGBS is designed to show Daylight Saving Time. Accordingly, the sundial is displayed from the first Sunday in April through the last Sunday in October, roughly equivalent to the duration of the growing season in Washington, D.C. No. 9 - BGMD_MVC-004F3.jpg Sundials must be corrected for longitude as well as the Equation of Time (EoT) so that Solar Time reads the same as Standard Time. Solar Noon occurs approximately eight minutes later in Wheaton, MD (~77dW) than it does on the Standard Time Meridian (STM) for the Eastern Time Zone (75dW); the EoT may be as much as 16 min. fast or 14 min. slow. The BGBS features a built-in correction for the longitudinal offset from the STM; add or subtract the EoT as appropriate. Monday, 26 July 2004. Time shown = ~1:26 p.m. EDT. ROW 4 No. 10 - BGMD_MVC-001F.jpg The BGBS is located in the 'Trial Garden,' alongside the Conservatories at Brookside Gardens (shown background). The sundial and surrounding gardens are planted with a beautiful array of colorful flowering plants. No. 11 - BGMD_MVC-004F.jpg The lower part of the dial face is planted with Portulaca 'Sundial Mix'; later in the growing season, Chrysanthemum replaces the Portulaca. In late-October, the gnomon is removed and stored for the winter; the circular bed is cleared and planted with tulip bulbs for the spring. After the tulips finish blooming in the spring (about the time Daylight Saving Time goes into effect), the gnomon is reinstalled for the summer. No. 12 - BGMD_MVC-002F2.jpg Rudbeckia hirta 'Cherokee Sunset.' Common name: Black-eyed Susan. Other flowers: Petunia hybrida 'Tidal Wave Silver' (lower-left corner, lavendar). ROW 5 No. 13 - BGMD_MVC-003F2.jpg Sunflowers (shown background). Other flowers: Cleome hasslerana - Spider Flower (lower-left, lavendar); Pennisetum setaceum Rubrum - Purple Fountain Grass (upper-right, spike-y grass); Tithonia 'Fiesta Del Sole' - Mexican Sunflower (lower-right, orange); Petunias (extreme lower-left corner, mix of colors). No. 14 - BGMD_MVC-004F2.jpg Close-up photo, Sunflowers. Other flowers: Catharanthus roseus var. - Vinca (lower-left corner, magenta); Lagerstroemia - Crepe Myrtle (upper-left, lavendar); Helianthus annus - Sunflower (upper-right); Celosia plumosa 'New Look Red' (lower-right, red spike-y flowers). No. 15 - BGMD_MVC-005F2.jpg Petunia hybrida 'Tidal Wave Silver' and Ipomoea batatas 'Marguerite.' Common name: Sweet Potato Vine (a member of the same genus as Morning Glory). Other flowers: Scaevola (upper-left, purple).