We carried out a search for companions to B stars using the adaptive optics system of the Advanced Electro-Optical System 3.6 m telescope. We observed 70 B stars in the I band, finding 16 companions, 10 of which are newly discovered companions. For each system with a detected companion we give its measured astrometry and differential magnitude. We then put the observation in context of the system's known multiplicity and provide a somewhat crude estimate of its spectral type based on the single differential magnitude measurement. The separations range from 0.2 00 to 7.31 00 , and the differential magnitudes range from 1:41 AE 0:01 to 10:1 AE 0:5. Finally, we present a list of the null detections and discuss the implications of null detections of selected stars.

We present a statistical analysis of r 0 and 0 measurements collected over the last 2 decades at 18 different sites. Although the site altitudes varied from sea level to 3 km, the major distinguishing feature between average r 0 values was the presence or absence of a turbulent, atmospheric boundary layer above the surface. For locations without a strong boundary-layer inversion, the mean coherence length, r 0 , was 93 Ϯ 6 mm and the mean isoplanatic angle, 0 , was 9.4 Ϯ 0.5 rad. Where a boundarylayer inversion was present, the corresponding values for r 0 and 0 were 53 Ϯ 2 mm and 6.5 Ϯ 0.5 rad, respectively.

We have investigated the temporal variability and statistics of the "instantaneous" Strehl ratio. The observations were carried out with the 3.63-m AEOS telescope equipped with a high-order adaptive optics system. In this paper Strehl ratio is defined as the peak intensity of a single short exposure. We have also studied the behaviour of the phase variance computed on the reconstructed wavefronts. We tested the Maréchal approximation and used it to explain the observed negative skewness of the Strehl ratio distribution. The estimate of the phase variance is shown to fit a three-parameter Gamma 1 Based on data from the Maui Space Surveillance System, which is operated by Detachment 15 of the U.S. Air Force distribution model. We show that simple scaling of the reconstructed wavefronts has a large impact on the shape of the Strehl ratio distribution.

Haleakala is the site for numerous telescopes, but the amount of published information on summit conditions is small. We seek to rectify that by presenting several years' worth of data on weather (cloud statistics, relative humidity, temperature, wind speed, and wind direction) and seeing conditions. We also examine the dependence of seeing on wind. Our goal is to provide observers with information that will help them better choose the timing of their observations, and to build up a climatological record for the site.

Abstract:An understanding of wind speed and direction as a function of height are critical to the proper modeling of atmospheric turbulence. We have used radiosonde data from launch sites near significant astronomical observatories and created mean profiles of wind speed and direction and have also computed Richardson number profiles. Using data from the last 30 years, we extend the 1977 Greenwood wind profile to include parameters that show seasonal variations and differences in location. The added information from our models is useful for the design of adaptive optics systems and other imaging systems. Our analysis of the Richardson number suggests that persistent turbulent layers may be inferred when low values are present in our long term averaged data. Knowledge of the presence of these layers may help with planning for adaptive optics and laser communications.