June 12, 2007J. Harvey DFG-NSF Astrophysics Research Conference SOLIS A Long, Careful Look at the Sun Jack Harvey National Solar Observatory

DFG-NSF Astrophysics Research Conference June 12, 2007J. Harvey

SOLISSOLIS A Long, Careful Look at the SunA Long, Careful Look at the Sun

Jack HarveyJack Harvey

National Solar ObservatoryNational Solar Observatory


Overview

• Why

• What

• Drivers/design

• Some data samples

• Opportunites for German-US collaboration

• Summary


Why Study the Sun?

Our only vital astronomical object It’s the astrophysics of here and now As challenging as any area of astrophysics Practical applications (space weather, climate)

Often first use of new photonics AAAS Journal Science posed 125 Big

Science questions for its 125th anniversary issue of July 1, 2005; one was

“What drives the solar magnetic cycle?”


German and US Solar Programs Long histories of observation and theory Long history of beneficial collaborations Both countries now building modern 1.5 m

facilities for short-term optical observations Both interested in advanced photonics Germany ceased long-term optical

(synoptic) programs US invested in SOLIS synoptic program


What is SOLIS?

Synoptic Optical Long-term Investigations of the Sun

State-of-the-art instruments designed to measure the Sun regularly for 25 years

Replaces and modernizes successful NSO program started in 1973

SOLIS started regular observations 2003 Science goals aimed at solar activity Decadal Survey urges a 3-station network


Virtues of SOLIS VSM

Regular full-disk vector magnetogramsFull Stokes spectral profile informationChromospheric magnetogramsHigh efficiency optical path (6×107 ph/pix/s)Low polarization telescopeLong projected life (~2028)Open data archiveComplements related space projects (e.g.,

SOHO, TRACE, Hinode, STEREO, Sunrise, SDO, Solar Orbiter, etc.)


Why Long-Term?

Magnetic solar cycle is 22 years Many solar processes are slow Synoptic data taken since 1973 still widely

used for today’s research and to address originally unforeseen questions

Maximize the scientific payoff for the initial investment


48 Solar Rotations


Why Frequent?

Many basic solar processes occur rapidly Increased chance of capturing rare events Minimize observational gaps Smooth out noisy local solar processes Provide frequently updated boundary

conditions for data assimilation modeling Prompt forecasting of space weather


SOLIS on Kitt Peak


•Long-slit spectropolarimeter

•80-cm window, 50 cm aperture

•Helium filled

•Single crystal Si secondary

•Ferroelectric LC modulators

•High reflectivity coatings

•All light used

Vector SpectroMagnetograph

German tip-tilt mount

German beamsplitters


SOLIS VSM 104 Dynamic Range2004 January 6


Field strengthAzimuth in sky planeInclination to line of sight

SOLIS VSM Vector Magnetogram



SOLIS VSM – Hinode XRT


SOLIS Collaboration Opportunities

1. Short-term campaigns In progress (e.g. Solanki; Wilhelm)

2. Instrumental improvements3. Long-term associations

Model – Data comparisons Gregor ESA Solar Orbiter

4. Partners in building a global SOLIS network


Summary

Long-term study of Sun is vital Advanced photonics as used in SOLIS

enable that research SOLIS provides unique data waiting to

be exploited SOLIS welcomes collaborations!

http://solis.nso.edu

Documents

June 12, 2007J. Harvey DFG-NSF Astrophysics Research Conference SOLIS A Long, Careful Look at the Sun Jack Harvey National Solar Observatory