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The SECCHI Campaign. Jean-Pierre Wuelser SECCHI Consortium Meeting Orsay. Outline. What is a SECCHI Campaign? The first SECCHI Campaign: May 2007 Campaign features and constraints Science objectives A possible campaign observing program Discussion Science focus Observational approach.
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The SECCHI Campaign Jean-Pierre Wuelser SECCHI Consortium Meeting Orsay
Outline • What is a SECCHI Campaign? • The first SECCHI Campaign: May 2007 • Campaign features and constraints • Science objectives • A possible campaign observing program • Discussion • Science focus • Observational approach
What is a SECCHI Campaign? • SECCHI Campaigns are designated periods of time where • Each STEREO observatory receives two DSN downlinks per day • SECCHI receives twice the daily telemetry volume, i.e., approx. 9.3 Gbit/day/observatory instead of 4.65 • SECCHI gets a total of 4 weeks of campaign time during the primary science mission • SECCHI plans to have 2 campaigns of two weeks each • SECCHI Campaigns must be scheduled long in advance • The campaign dates cannot be adjusted based on solar activity
The First SECCHI Campaign • The focus of the first SECCHI Campaign are observations at an observatory separation angle best suited for • Stereoscopic observations in the classical sense • 3D reconstruction using tie point methods with visual interaction • Primary science objective: Investigate CME initiation in the low corona • The first SECCHI Campaign: • Starts on May 4 and ends on May 17 • Observatory separation: approx. 7 degrees • Ends just before the beginning of the SOHO keyhole period • Unfortunately during the Hinode eclipse season • May impact the availability of data from the optical telescope in particular
Campaign features and constraints • SECCHI will be able to downlink twice the data volume of the regular synoptic program • Data rate implications: • Average SECCHI data rate during campaign: 108 kbit/sec • Peak transfer rate SECCHI to SSR: 153 kbit/sec • SECCHI will be able to downlink almost as much data as it could possibly transfer to the Solid State Recorder • There is not much point in using the circular event buffer during the SECCHI Campaign • Continuous high cadence observations, no burst mode • During the campaign, the data rate to the SSR will be similar, or slightly lower as in the case of a synoptic + event buffer observing program
Science Objectives • Primary objective: investigate initiation of CMEs in the low corona • Analyze magnetic topology in the low corona during CME initiation with EUVI stereoscopic imaging at high cadence • Observe initial acceleration of CMEs and associated phenomena in the 1-2 solar radii range • Investigate broad range of other transient phenomena in the low corona • Acquire continuous dataset of low coronal observations for a half solar rotation at a cadence and wavelength coverage not possible with the regular synoptic program • Dataset to be useful for a broad range of CME and non-CME studies
A Possible Campaign Observing Program • HI and Cor2: same as synoptic program • HI-1 : 40 min cadence, HI-2 : 2 hour cadence • Cor2 : 15 min cadence, polarization sequence every 30 min • Cor1: double synoptic cadence • 5 min cadence of 1k x 1k polarization sequences • EUVI: • 284 : 5 min cadence, ICER6 • 171, 195, 304 : 5 min cadence, ICER4 • 171 : fill in to 1.25 min cadence w/ ICER6 • 304 : fill in to 2.5 min cadence w/ ICER6
Coordination with Other Missions • SOHO • EIT • LASCO • CDS • MDI • TRACE • Hinode • EIS • XRT • SOT • Coordination of limited FOV instruments to use same target, complementary cadence/FOV