"The worst thing in the world would be to have half the battlefield go out during the ceremony," Beltowski said.
The design is so effective that some years, some of the candles were still burning the morning after the event and clean-up volunteers have had to stamp them out, Charles said.
Beltowski said it takes at least a "good week" to manufacture the Antietam candles each year, with a two- to three-week turnaround time for the order.
"Once we have it (machinery) running and pressing them, it's not that terribly time consuming," she said.
But manufacturing the candles is only the beginning of the preparations for the event. Event coordinators also need 22 tons of sand, 24,000 little cups, and 24,000 paper bags -- brown, not white, because of the warm glow brown creates, organizers said. The cups and the bags come from Weiss Bros., a paper company in Hagerstown, said the battlefield's chief ranger, Ed Wenschhof.
More than 100 volunteers worked to pack the candles and sand into bags last month at the Washington County Agricultural Education Center, Charles said.
On Saturday, organizers will be at the battlefield before 7 a.m. to start unloading candles and dividing the battlefield into 35 quadrants, Charles said.
An army of volunteers will begin checking in at 8:30 a.m., she said. At least 1,200 are registered, but organizers expect the final number will be more than 1,400, Charles said.
The volunteers will use ropes, lasers and other methods to arrange the candles 15 feet apart in straight lines, she said. The process takes about four hours, with each volunteer placing an average of 22 to 26 candles, she said.
Some of the volunteers come from church groups, Scout troops and re-enactment groups, while others participate as individuals or families. They do it as a sign of respect and honor for the soldiers who died, she said.
"I have asked them for years, 'Why do you do this?'" Charles said. "Their reply is, 'We do not feel complete if we do not participate.'"
"It's very simple," she said. "It's from the heart."
If you go...
What: 20th annual Antietam National Battlefield Memorial Illumination
When: 6 p.m. to midnight, Saturday, Dec. 6
Where: Antietam National Battlefield near Sharpsburg. Vehicles begin the tour at the battlefield entrance on Md. 34, east of Sharpsburg (see map).
Cost: Free; donations accepted at the entrance.
Tips for visitors
Following are tips for attending the Antietam National Battlefield Memorial Illumination from an event official and the National Park Service Web site at www.nps.gov/anti/planyourvisit/luminary.htm:
o Vehicles tend to begin lining up as early as 1 p.m.
o Be prepared to wait in line for up to two hours.
o Plan to arrive with a full tank of gas.
o The wait tends to get shorter as the evening goes on, with the line beginning to move faster sometime between 8:30 p.m. and 11 p.m., event founder and chairwoman Georgene Charles said. The tour will stay open as long as there are vehicles in line, she said.
o Drivers are asked to use parking lights only and drive through slowly without stopping.
o Visitors are discouraged from walking the tour route on foot.
o The tour is about 5 miles long.
o There are no bathrooms along the route.
o If there is inclement weather, call 301-432-5124 to find out if the event has been postponed. If postponed, the illumination will be rescheduled for Dec. 13.