Eliminating the Coriols Effect in Liquid Mirrors

If uncorrected, the Coriolis force due to the rotation of the Earth causes significant aberration of images produced by large liquid-mirror telescopes. We show that this problem can be eliminated by a fixed compensating tilt of the liquid-mirror rotation axis. The required tilt angle, which is a function of latitude and mirror rotation rate, is of order 10 arcsec for current telescopes. This result removes the last fundamental obstacle to achieving diffraction-limited performance with large liquid mirrors.Comment: 8 pages 1 figure, submitted to PAS

A Survey of Galaxy Redshifts from Low-Resolution Slitless Spectra: Suggestion of Large-Scale Structures at Z ~0.1

We have conducted a galaxy survey based on low-resolution slitless spectra taken from the automated CFHT-Laval survey. We present redshift distributions for 522 galaxies distributed in 4 distinct regions of the sky. Redshifts are determined from the shifted positions of the 4000 A. stellar break using an automated break-finding algorithm. The redshifts so obtained have a precision of < 3000 km s-1, good enough to trace the large-scale distribution of galaxies. The most striking feature of the survey is an apparent excess of galaxies at z ~ 0.1 in 8 of the 10 fields probed. Although the statistical significance of the peaks appears marginal (~ 2.5s per field) after taken in account the small-scale galaxy clustering, the peaks may nevertheless reveal the existence of large-scale structures at z ~ 0.1, indicating that the known large structures in the local universe are not unusual.Comment: 28 pages + 4 figures, uuencoded-compressed-Postscript, EFB0829