Synoptic observations are indispensable in studies of long-term effects pertinent to variation in solar radiative output, space weather and space climate, as well as for understanding the physics of global processes taking place on our nearest star. Synoptic data also allow putting the Sun in the context of stellar evolution. Historically, the main-stay of such observations has been ground-based, although the improving longevity of space-borne instruments puts some space missions into the category of synoptic facilities. Space- and ground-based (synoptic) observations are complementary to each other; neither is inferior or superior to the other. Ground-based facilities can have a long-term (50 years+) operations horizon, and in comparison with their space-based counterparts, they are less expensive to operate and have fewer restrictions on international collaboration and data access. The instruments can be serviced, upgraded, and cross-calibrated to ensure the continuity and uniformity of long-term data series. New measurements could be added in response to changes in understanding the solar phenomena. Some drawbacks such as day-night cycle and the variable atmospheric seeing can be mitigated e.g., by creating the global networks and by employing the adaptive optics. Furthermore, the ground-based synoptic observations can serve as a backbone and a back-up to space-based observations. In my talk I will review some existing ground-based synoptic facilities, describe plans for future networks, and outline the current efforts in strengthening the international collaboration in synoptic solar observations from the ground.

It is not uncommon to see the references to recent (cycle 24) solar activity as “exceptionally low” or as an “extended long-term decline”. But how would we know that the current level of activity is unusual if we did not have historical data taken over many cycles? How would we know, for example, what are the strongest field strengths in sunspots and how they change with time or that the amplitude of next cycle could be defined by the strength of polar field in previous cycle if we did not have long-term records of solar activity? Truly, synoptic observations feed future research to solve issues that may not be identified at the time when data are acquired. In my talk, I will discuss the current state of long-term synoptic programs and present results of my recent projects on reconstructing the solar activity using historical data.

Mario Bisi, Anatoli Petrukovich, Ying Liu

Having satellites positioned in-orbit at both Lagrangian L5 and L4 points offers several major advantages. For example, the L5 vantage point provides an early view of the solar surface, which Earth will be facing 4-5 days later. In turn, the L4 viewing point enables a better view of the source regions of eruptions responsible for SEPs affecting the near-Earth environment. Taken together, observations from L4 and L5 cover about 83% of solar surface, which will significantly improve both short- and long-term forecasts. However, in the most likely scenario that funding will support only a single L5 mission, not both, one alternative that the space weather community may want to explore is to encourage other spacefaring nations such as Russia, China, and India, to launch their own spacecraft to L4 in close coordination with the L5 mission. Launching two separate spacecraft to L4 and L5 will allow us to reap the benefits of having two new vantage points for space weather in addition to the L1 vantage point, to more-fully share the costs of such combined missions, and avoid the restrictions related to the transfer of technology (predominantly affected the L5 and L1 concepts to date).

In 2011, the International Astronomical Union (IAU) created a working group now known as the IAU inter-Division B-E working group on Coordination of Synoptic Observations of the Sun. The mission of this group is to facilitate the international collaboration in synoptic long-term solar observations, which includes past, current, and future synoptic programs, preservation, calibration, and access to synoptic solar data products. This presentation provides a brief overview of activities of the group and outlines the current issues facing the synoptic solar groundbased observations.