Despite a series of deadline confusions, the residents of Observatory Hill last night persisted in voicing their support of a down-zoning petition which they hope will halt construction of the proposed Radcliffe athletic facility.

The Cambridge Planning Board last night heard the arguments for and against the petition for the second time since a similar hearing occured last November. The board then recommended to the city council that the property be down-zoned from a C-2 zoning to a C-1 zoning, reducing the building height restriction from 75-35 feet.

The residents requested in September that the property be down-zoned for residential use.

Confusion concerning the time limitation on the petition resulted in expiration of the request in December, so the residents must repeat their efforts to restrict Harvard's building space.

The residents' arguments in favor of the petition emphasized the "character and "charm" of the neighborhood. About 25 neighbors attended the hearing, most of them voicing support of the petition, citing such reasons as the importance of preserving open space in the mostly residential section of north Cambridge.

"Children fly their kites there, people walk their dogs there, students sit in the park, and it must stay that way," John Coolidge, a resident of the area, said last night.

Donald C. Moulton, assistant vice-president for community affairs, said at the meeting Radcliffe has not yet requested a building permit for the facility.

Moulton added, "The cloud of down-zoning is still hanging over us."

Burton I. Wolfman, administrative dean of Radcliffe College, told members of the planning board last night that Radcliffe opposed the petition, adding that Radcliffe would like to complete construction of the athletic facility by the Radcliffe Centennial, which will be celebrated next June.