The month was well above the average for observing. 123 plates were secured on 27 nights with a total observing time of 145.6 hours. The ten-year average for the month shows 131 plates on 21 nights with a total of 104.5 hours. Approximately 1486 persons visited the observatory during the week.
Director J. S Plaskett compiled B-type velocities and computation of the constants of galactic rotation and K term for different groups of O and B stars. Handled the usual administrative work and correspondence.
[Plaskett and Harper spoke to the RASC on May 1, 1930 on some unknown aspects of the DAO telescope. This included being challenged on the bills for “rock candy” used during the sivering process, Ed.]
Assistant Director W. E. Harper worked 6 nights obtaining 58 plates. Measured for radial velocity 53. Some work revising periods of earlier binaries. Gave one seminar talk and prepared our portion of Departmental report.
Astronomer J. A. Pearce spent the month in computing. The 870 O- and B-type stars for which we have reliable values of the radial velocity were divided into various groups of types and magnitudes. Least-squares solutions were performed to yield values of the Rotation Term and K Term.
Astronomer C. S. Beals worked 8 nights obtaining 13 plates of faint stars. Measured 21 plates for wave length and radial velocity. Computed velocity for IS camera and wave-length reduction tables in red for ISS. Gave one seminar talk.
Assistant Astronomer R. O. Redman obtained 21 plates on 7 nights. Measured 50 plates for K ‘giant’ programme. Gave one seminar talk.
Assistant Astronomer A. Pannekoek worked 6 nights, securing 31 plates. Preparing method for impressing comparison on plates in study of line intensities.
[Prof. Pannekoek was visiting the observatory from the Astronomical Institute of the University of Amsterdam, Ed.]
Article on the visit by Prof. Pannekoek to the DAO
Computer S. N. Hill prepared two velocity curves of 103 Tauri for publication. Computational and other related work on B stars.
Senior Clerk-Stenographer L. M. Blake handled correspondence, reports and accounts. Library assistance and card catalogue of publications brought up to date. Envelopes for spectrograms.
Instrument Maker Foreman T. T. Hutchison assisted in observing on 19½ nights/ Made some new connections to telescope and kept it in running order.