O occultations observed at Boston
O occultations of Aldebaran at Altona
O pendulum experiments
O random walk de Lévy aplicado aos mapas de variâncias
O several double stars
O small variable star in Serpens
O some instruments invented by him
O sopro do magnetar
O Stars and OB Associations Observed from EINSTEIN.
O stars and supergiants south of declination -53.0 .
O stars and the interstellar medium
O Stars as a Probe of Gas Densities in the Low-Density Interstellar Medium
O Stars as Probes of the Interstellar Medium
O Stars in Transition. I. Optical Spectroscopy of Ofpe/WN9 and Related Stars
O Stars in Transition. II. Fundamental Properties and Evolutionary Status of Ofpe/WN9 Stars from Hubble Space Telescope Ultraviolet Observations
O telescópio remoto do Observatório Abrahão de Moraes - Obelix
O terrestrial refractions
O the adoption of a standard of optical power
O the appearance of stars on the moon's disc
O the application of a camera lucida to a telescope