The Rotation and Mass of NGC 1084.

The rotation-curve of NGC 1084 was obtained from measures of the Ha and [N ii] X 6583 emission lines on spectra taken at the prime focus of the 82-inch telescope with a long slit. The rotation-curve extends to about 55" from the center; in this region the curve has flattened and is beginning to turn over. An integral equation was solved for the mass distribution under the assumption that the equidensity surfaces are similar spheroids. For assumed values of c/a ranging from T1 to 1 the total mass is 1.6 X 1010 M0. The mass-to-light ratio from the photographic magnitude is 0.8.