417 research outputs found
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
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