David W. Latham, senior lecturer on Astronomy, and Owen Gingerich, Professor of Astronomy, once hired an airplane to tow a banner over the yard during shopping period to advertise their Core course, "Science A-17: The Astronomical Perspective."

But Latham says most students didn't seem to notice the moving billboard.

"The bottom line is I think the effort got us one student," he says.

As shopping period gets underway this week, some professors say they find the Harvard tradition to be a nuisance because they have to sell their classes to students in jam-packed, frenzied conditions.

Still others, however, say they are in support of shopping period because it offers students a valuable time to find the classes that best suit their interests.

Latham says whether or not he tries to sell his course depends on how many students show up during shopping period.

"It depends on whether I've got too many or too few students," he said. "Also it depends on how many T.F.s [teaching fellows] we're committed to."

Jay M. Harris, Wolfson Professor of Jewish Studies, says he usually feels pressure to sell his departmental course offerings to students.

"[I try to sell] department classes, since I am in a department that attracts limited students," he says.

But Harris, whose Core class, "Moral Reasoning 54: `If There Is No God, All Is Permitted," was standing-room only yesterday, says he does not have the same concern with Cores.

In fact, shopping period may necessitate some reorganization.

"In any event, enrollment will be higher than the Core office allowed me to plan for," he says.

Harris and other faculty members say there are some negative aspects to shopping period, such as overcrowding, lack of handouts and students leaving mid-lecture.

It is difficult to convey the merits of an entire course in only a few lectures, Harris says.

"[Shopping]does not tell people what they need to know, since so many of us feel that essential material cannot be presented then or at least not until the last day [of shopping period," he says.