EVALUATION OF MAUNA KEA, HAWAII, AS AN OBSERVATORY SITEMorrison, D.; Murphy, R. E.; Cruikshank, D. P.; Sinton, W. M.; Martin, T. Z.
doi: 10.1086/129449pmid: N/A
Data are presented describing the qualities of Mauna Kea as an observatory site. Based on four years of experience, an average of 56% of nights are photometric and another 20% are spectroscopic. The median seeing is between 1 and 1.5 arc seconds, and the sky is very dark. Because of its altitude (4200 m), the site is dry and has high transparency and low sky brightness in the infrared. The median 17- to 28- m extinction coefficient is 0 '34 air mass-1. Data obtained as part of the NASA 10- m sky noise survey indicate that low noise conditions prevail at almost all times that the sky is photometric. Key words: observatory site - Hawaii - infrared - seeing - photometry
A MULTICHANNEL SPECTROPHOTOMETERRodgers, A. W.; Roberts, R.; Rudge, P. T.; Stapinski, T.
doi: 10.1086/129450pmid: N/A
A 33-channel spectrophotometer used at the Cassegrain focus of the 74-inch reflector at Mount Stromlo is described. The instrnment status and data system are under remote interactive computer control. The photomultiplier cooling which is accomplished by circulating dry nitrogen at -65 C through the cold boxes results in high thermal stability at the cathedes. The performance of the spectrophotometer under observing conditions is described. Key words: instrnmentation - spectrometer
THE AUREOLE OF A STAR IMAGEPiccirillo, John
doi: 10.1086/129452pmid: N/A
Telescope star-image profiles for various observing conditions are compared. Effects of mirror realuminization, secondary support diffraction spikes, and atmospheric haze are shown. A modification to the previously found inverse-square aureole is discussed. Key words: star image profile
LUMINOSITY AND VELOCITY DISTRIBUTION OF HIGH-LUMINOSITY RED STARS,NEAR THE SUN. I. THE VERY YOUNG DISK POPULATION.Eggen, O. J.
doi: 10.1086/129456pmid: N/A
The luminosities and space motions of the very young disk-population red stars near the sun are discussed on the basis of UBVRI photometry and accurate apparent motions. The sample includes all stars brighter than VE = 5" O as well as some objects apparently fainter because of interstellar reddening. The FK 4 system of proper motions, with corrections to Newcombe's precessional constant, is found to be preferred to the N 30 system. Very young disk stars are defined by the velocity distribution of the early B-type stars and about one-third of the sample of luminous red stars in this population belong to the Pleiades group. Approximately half of the remaining stars in the sample are probably members of another group with V = -18 km sec-1. The Pleiades group also contains the clusters NGC 2287 and NCC 2516 in addition to the a Persei cluster while the group with V = - 18 km sec -1 contains the clusters Collinder 121 and IC 2391. The very young disk population in this sample appears to be divided between objects of 5 and 9 solar masses in the ratio 3/2 with a half dozen stars of higher mass. Key words: stellar population - space motions - photometry
OAO-2 AND MARINER 9 ULTRAVIOLET OBSERVATIONS OF Δ PERSEIMolnar, Michael R.
doi: 10.1086/129457pmid: N/A
The star 8 Per is identified as a variable star from OAO-2 photometry although the data are insufficient to determine the period or the exact nature of the photometric variations. The Mariner 9 spectrometer observations show a strong variable emission feature at Al 650, tentatively identified as Ca ii (UV1 multiplet). Key words: variable stars- ultraviolet stellar spectra - ultraviolet photometry