MEASUREMENT OF HIGH-DEGREE SOLAR OSCILLATION FREQUENCIES

We present m-averaged solar p- and f-mode oscillation frequencies over the frequency range 1.8 < nu < 5.0 mHz and the spherical harmonic degree range 100 less than or equal to l less than or equal to 1200 from full-disk, 1000 x 1024 pixel, Ca II intensity images collected 1993 June 22-25 with a temporal cadence of 60 s. We itemize the sources and magnitudes of statistical and systematic uncertainties and of small frequency corrections, and we show that our frequencies represent an improvement in accuracy and coverage over previous measurements. Our frequencies agree at the 2 mu Hz level with Mount Wilson frequencies determined for l less than or equal to 600 from full-disk images, and we find systematic offsets of 10-20 mu Hz with respect to frequencies measured from Big Bear and La Palma observations. We give evidence that these latter offsets are indicative of spatial scaling uncertainties associated with the analysis of partial-disk images. In comparison with theory, our p-mode frequencies agree within 10 mu Hz of frequencies predicted by the Los Alamos model but are as much as 100 mu Hz smaller than frequencies predicted by the Denmark and Yale models at degrees near 1000. We also find systematic differences between our n=0 frequencies and the frequencies closely agreed upon by all three models.