THE IMAGING VECTOR MAGNETOGRAPH AT HALEAKALA

We describe an instrument we have built and installed at Mees Solar Ob servatory on Haleakala, Maui, to measure polarization in narrow-band s olar images. Observations in Zeeman-sensitive photospheric lines have been made for nearly all solar active regions since the instrument beg an operations in 1992. The magnetograph includes a 28-cm aperture tele scope, a polarization modulator, a tunable Fabry-Perot filter, CCD cam eras and control electronics. Stokes spectra of a photospheric line ar e obtained with 7 pm spectral resolution, 1 are sec spatial resolution over a field 4.7 are min square, and polarimetric precision of O.1%. A complete vector magnetogram observation can be made every eight minu tes. The flexibility of the instrument encourages diverse observations : besides active region magnetograms we have made, for example, compos ite Vector magnetograms of the full solar disk, and H alpha polarizati on movies of flaring regions.