Launched on SOHO in December 1995, the MDI instrument took its 10 millionth filtergram in early April, 1997. The instrument and spacecraft have performed admirably since commissioning, providing over a year of virtually uninterrupted time series of velocity and intensity measurements at moderate resolution, a continuous 60-day time series of full disk 4" velocity and line depth maps, monthly 72+ hour time series in various observables, a host of daily 8-hour campaigns, and full-disk magnetograms every 96 minutes. Another uninterrupted 90-day interval of nearly full data recovery is scheduled to be completed in mid July. Various scientific results using MDI data are being presented at this meeting. About a dozen terabytes of data sets have been created and archived and normal pipeline processing is now completed soon after retrieving the data, typically less than a month after the observations are made. Most of the data products are generally available on the WWW, see http://soi.stanford.edu. Selected data are available in near real time. The SOI team welcomes collaborations. Routine and extraordinary calibrations along with analysis of scientific data sets allow us to make good estimates of the noise and understand many of the sources of systematic errors in the instrument. In almost every respect the instrument performs as well or better than expected before launch, the primary limitations being photon noise on the short term and fixed or slowly varying offsets on the long term. We have found that the Michelsons are somewhat more sensitive to operational temperature variations than was expected, adding some additional constraints on our observing sequences.
AAS/Solar Physics Division Meeting #28
- Pub Date:
- May 1997