VLBI Observations of ALSEP Transmitters

The technique of differential very-long-baseline inteferometry (VLBI) Apollo Lunar Surface Experiments Package was used to measure the relative positions of the (ALSEP) transmitters at the Apollo 12, 14, 15, 16, and 17 lunar landing sites with uncertainties less than 0.005 sec of the geocentric arc. These measurements yielded improved determinations of the selenodetic coordinates of the Apollo landing sites, and of the physical libration of the moon

Analysis of lunar laser ranging data for Earth dynamics applications

The effects of elasticity and of tidal friction within the Moon were incorporated into the numerical model of the Moon's rotation which was used in an effort to determine the axial rotation of the Earth, as measured by Universal Time. Some 2,651 normal points representing ranges measured to Lunokhod 2, and to the Apollo 11, 14, and 15 retroflectors were analyzed. Smoothed estimates derived from the lunar rangefinding were compared with smoothed values published by the International Bureau of Time, in the 1968 and 1969 systems. The derived values at the observation sight were connected to corresponding values at the Conventional International Origin, using the BIH data for polar motion. Differences are discussed

Precision selenodesy and lunar libration through VLBI observations of ALSEPs

Data from 500 observation series, each one representing about five hours' continuous observation of a pair of ALSEPs by differential very long baseline interferometers (VLBI) have been compiled on magnetic tape. The theoretical models used to calculate the rotation of the earth, the orbit of the moon, the libration of the moon, and the basic VLBI observable were improved substantially. Analysis of data from long spans of VLBI observations was begun

Miniature interferometer terminals for earth surveying

A system of miniature radio interferometer terminals was proposed for the measurement of vector baselines with uncertainties ranging from the millimeter to the centimeter level for baseline lengths ranging, respectively, from a few to a few hundred kilometers. Each terminal would have no moving parts, could be packaged in a volume of less than 0.1 cu m, and would operate unattended. These units would receive radio signals from low-power (10 w) transmitters on earth-orbiting satellites. The baselines between units could be determined virtually instantaneously and monitored continuously as long as at least four satellites were visible simultaneously

Applications to Earth physics: Very-long-baseline interferometry and data analysis

A range of very long baseline interferometry experiments applied to Earth physics are covered

Analysis of the Capability and Limitations of Relativistic Gravity Measurements Using Radio Astronomy Methods

The uses of radar observations of planets and very-long-baseline radio interferometric observations of extragalactic objects to test theories of gravitation are described in detail with special emphasis on sources of error. The accuracy achievable in these tests with data already obtained, can be summarized in terms of: retardation of signal propagation (radar), deflection of radio waves (interferometry), advance of planetary perihelia (radar), gravitational quadrupole moment of sun (radar), and time variation of gravitational constant (radar). The analyses completed to date have yielded no significant disagreement with the predictions of general relativity

European immigrant designers and their influence on American graphic design: 1920-1950

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Supporting the success of online students who are deaf: Lessons presented at #SWDE2017

Guest post for the "Teaching & Learning in Social Work: Exploring Ways to Enhance Life-Long Learning for Professional Practice" blog by Laurel Hitchcock. (2017, June 23). Post available at http://www.laureliversonhitchcock.org/2017/06/23/supporting-the-success-of-online-students-who-are-deaf-lessons-presented-at-swde2017

Reflection Journals - Examples of using this powerful tool to help students synthesize course content

For new and experienced online instructors, or those who work with them, this interactive session will share examples of well received reflection journal assignments from online courses at Columbia University. The presenters will open by touching on research on the value of reflection journals, sample uses of reflection journal assignments, and how to provide instructor feedback and grading to deepen student work on future journal entries while maintaining a feasible instructor workload. Next, the presenters will share examples of reflection journal assignment instructions, grading rubrics, and lessons learned from two online courses. Finally, the presenters will facilitate a chat-based discussion to encourage the session participants to share their experiences, advice, and questions. Most learning management systems, including Blackboard and Canvas, include a journal tool. This session will help instructors share and spark ideas of ways to use this tool effectively in their own online courses, regardless of the course topic or academic discipline. The presenters will be Beth Counselman Carpenter, Assistant Professor, Southern Connecticut State University's School of Health and Human Services; and Matthea Marquart, Director of Administration, Online Campus, and Lecturer, Columbia University School of Social Work