From: Loren Acton – acton@mithra.physics.montana.edu
Announcement of the Yohkoh Legacy Archive
The Japan/US/UK solar physics mission Yohkoh was operational from
September 1991 until 14 December 2001. Yohkoh returned quality images in
soft and hard x-rays as well as spectroscopic observations in soft x-rays
to gamma-rays. Because of the long duration of the mission, good time
resolution and the high-temperature bias of the Soft X-ray Telescope (SXT)
these data are unique and of continuing value for science. We are pleased
to announce the formal release of the Yohkoh Legacy data Archive (YLA) at
http://solar.physics.montana.edu/ylegacy/ . YLA
data are also available via the Virtual Solar Observatory.
SXT image data from level-1 to level-3 are available in both FITS and XDA
(Yohkoh specific) formats. Level-1 and 2 images are fully corrected and
calibrated. For the level-2 composite full-sun (FFI) data products each
image has a corresponding uncertainty image giving the statistical and
decompression error for each pixel. The level-3 FFI images are optimized
for viewing as a movie and are not appropriate for quantitative photometric
analysis.
The “Quick Look SXT” section provides convenient browse-entry to the
full-sun level-1 and level-3 (composite) images from the SXT as well as
useful information, through annotated GOES plots, of Yohkoh observational
coverage for every day of the mission. Overlays on the full-frame
pictures of the field of view of SXT partial frame images (PFI) are very
helpful in the choice and use of the faster cadence, higher resolution,
PFI. The SXT Movie Maker section enables flexible creation of time-lapse
movies from level-3 full-sun images.
Reduced data from the Hard X-ray Telescope (HXT), the Bragg Crystal
Spectrometer (BCS) and the Wide Band Spectrometer (WBS) are presented in
the “Flare Catalogs, HXT/WBS/BCS” section. The “SXT obs-log Inquiry Form”
and “YLA/SXT data Search” features of the YLA aid efficient identification
of data of interest. Extensive documentation of Yohkoh operations and
calibration are included in the YLA. Software for analysis of YLA data may
be found in SolarSoft (SSW). Our helpful YLA e-consultant service may be
addressed at yla@solar.physics.montana.edu.
The YLA is supported through the Virtual Observatories for Heliophysics
Data Program of NASA under grant NNX09AH64G. We gratefully acknowledge the
assistance of our Japanese, US and UK colleagues in the creation of the
YLA, especially S. Freeland who contributed much to the SSW aspects
of the YLA.