Magnetogram Users Group Role of the MUG –Charge –Functioning –Agenda Scientific Objectives & Functional Requirements –One person's noise is another’s signal GONG 101 –What it is now & how we got here

MUG Charge The GONG Magnetogram Users’ Group [MUG] provides a forum for the users of the GONG magnetograms to give feedback and advice to the GONG Program on the functionality, priorities, data processing specifications, etc. for the production of scientifically useful GONG magnetograms Members are appointed by the GONG Director to represent all of the scientific uses of the magnetograms. The MUG will meet at least once a year and prepare a meeting report, which will be publicly available.

Structure of the Meetings Executive Sessions Exit Interview Written Report Chair – provide an external focal point, develop agenda, coordinate report Tel/Video/Online Conf’s – as needed Other activities; e.g. “Hare & Hounds”

NSO Mission Statement The mission of the National Solar Observatory is to advance knowledge of the Sun, both as an astronomical object and as the dominant external influence on Earth, by providing forefront observational opportunities to the research community. The mission includes the operation of cutting edge facilities, the continued development of advanced instrumentation both in- house and through partnerships, conducting solar research, and educational and public outreach. NSO accomplishes this mission by: providing leadership for the development of new ground-based facilities that support the scientific objectives of the solar and solar-terrestrial physics community; advancing solar instrumentation in collaboration with university researchers, industry, and other government laboratories; providing background synoptic observations that permit solar investigations from the ground and space to be placed in the context of the variable Sun; providing research opportunities for both undergraduate and graduate students, helping develop classroom activities, working with teachers, and mentoring high school students; innovative staff research.

GONG Mission Statement The mission of GONG is to conduct a detailed study of the internal structure and dynamics of the Sun - as the prototypical star and as the source of the variable solar input to the Earth. GONG accomplishes this mission by Obtaining, and providing unfettered access to the scientific community of, the best possible imaged ground-based helioseismic data Conducting this program through at least a solar cycle Supporting both global and local helioseismology with significant analysis of the data. Obtaining magnetic field measurements for their correlative, as well as intrinsic, value Innovative staff research

Scientific Advisory Committee Sarbani Basu (Yale) Peter Gilman (HAO) Janet Luhmann (U. California-Berkeley) Robert Noyes* (Harvard-Smithsonian CfA) Philip Scherrer (Stanford) Mike Thompson (Sheffield U.) Alan Title* (Lockheed-Martin) Juri Toomre (U. Colorado/Chair) Roger Ulrich* (UCLA) *Charter Member Overall scientific guidance to the program

Data Users Committee [ DUC ] Thierry Appourchaux ( Institut d’Astrophysique Spatiale ) Sarbani Basu ( Yale ) Doug Braun ( Northwest Research Associates ) Thierry Corbard ( Obs de la Côte d’Azur ) Sylvain Korzennik ( Harvard-Smithsonian CfA ) Ed Rhodes ( USC ) Jesper Schou ( Stanford/Chair ) Philip Stark ( U. California-Berkeley )

Magnetogram Objectives, Characteristics, & Science Original –Provide a mask to remove effect of magnetic field on the oscillations  Once per hour GONG+ –Remove gap in time series  Continuous –What science can the GONG mags uniquely enable?

The Network

GONG “Classic” 256  256 pixels [  180, rectangular pixels  8” ] 60 s cadence Magnetograms once per hour at each site [shifted by 20 minutes between adjacent sites ] Mid-1996 through mid-2001

GONG  1024 pixels [ square, diameter  800,  2.5” ] 60 s cadence [ 30s & 16s available ] 90% duty cycle Optimized for intermediate scale velocity “Fourier Tachometer” [ Amplitude, Phase, & Mean of sine wave with /4  line width ] Magnetogram  Difference of velocity in opposite circular polarizations

Project  Program Magnetograms a full-fledged component What science can GONG magnetograms contribute to most effectively? What are the requirements to achieve that science?