December 1969 Brief 69-10776

NASA TECH BRIEF

NASA Teèh Briefs are issued to summarize specific innovations derived from the U.S. space program, to encourage their commercial application. Copies are available to the public at 15 cents each from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151.

Solar Activity History Model

A solar activity model has been devised to provide 25.38 days. The solar and reference meridian information on solar activity history. The model in- provide the origin for heliographic and longi- cludes data for plages, sunspots, filaments, and flares. tude. The purpose of the model is to enable scheduling Notes: which will indicate the time periods when solar ex- I. This information may be of interest to astronomers periments can be conducted. and meteorologists. Data were collected at various locations throughout 2. Requests for further information may be directed the world and recorded on tape for the computer. The to: motion of sunspots and pJages around the is de- Technology Utilization Officer pendent on their solar latitude. A reference coordinate Marshall Space Flight Center system was defined. The solar axis is defined to be in- Huntsville, Alabama 35812 dined 7.25 degrees from the pole of the ecliptic and Reference: TSP69-10776 to be oriented so that the ascending node of the solar Patent status: equator is 73.667 degrees + 50.25t seconds, where t is No patent action is contemplated by NASA. the time in years since 1850. The reference (0 degree) Source: Paul McKowen of meridian is the meridian that passed through the as- Martin Marietta Corporation cending node of the solar equator at mean Janu- under contract to ary 1, 1854, and whose interaction with the solar Marshall Space Flight Center equator moves around the equator with a period of (MFS-20529)

Category 01

This document was prepared under the sponsorship of the National Government assumes any liability resulting from the use of the Aeronautics and Space Administration. Neither the United States information contained in this document, or warrants that such use Government nor any person acting on behalf of the United States will be free from privately owned rights.