Solar Maximum Mission (SMM) Coronagraph/Polarimeter Data

The data from the Coronagraph/Polarimeter consist of digital images of the
solar corona taken through various filters at visible wavelengths.

The scientific objectives of the Coronagraph/Polarimeter were to observe
coronal structure, transient disturbances in coronal density and ejecta due to
eruptive prominences and flares, and to make long-term synoptic studies of the
corona to reveal how its structure relates to the solar activity cycle. Unique
features of this instrument include: multicolor filter photometry/polarimetry
including isolation of the H-alpha line emission and the 5303 A line of Fe XIV,
an optical design permitting the inner edge of the field of view to extend as
low as 1.5 solar radii, the ability to alter observing sequence programs in
response to the detection of flares by other instruments on the spacecraft as
well as commands from the ground, and the capacity for extensive data coverage,
as many as 250 images per day. The instrument consists of an externally
occulted coronagraph and linear polarimeter with a meshless SEC vidicon as a
detector. Spatial resolution in the outer corona is 10 arc-sec, set by the
vidicon pixel size. Exposures of 8-second duration yield good images with the
green filter (5014-5328 A band). A complete Polaroid sequence requires 7 min.
The field of view is approximately square, with a side length corresponding to
approximately 5.6 solar radii.

The instrument operated from the spacecraft launch, Feb. 14, 1980, until Nov.
24, 1980, when operations were interrupted by failure of the spacecraft fine
pointing control. In April, 1984, Challenger Shuttle astronauts restored the
SMM fine pointing capability, and C/P observations resumed until loss of
pointing on Nov.17, 1989.

Data sets exist in several locations. Recent data, catalogs and special
selected data sets are held at the SMM Data Analysis Center, NASA/GSFC.
The primary analysis and archive center is at the High Altitude Observatory,
NCAR, where many reduced and analyzed data products are held. Some data have
been deposited at NSSDC. Requests for further information or specific data
should be made initially to the SMM DAC or to HAO.

'A Catalogue of Mass Ejections Observed by the Solar Maximum Mission
Coronagraph', (St. Cyr, O.C., Burkepile 1990) includes events observed from
March 7, 1980 - September 23, 1980, and, after the in-orbit repair by the
Challenger, from June 8, 1984 until November 17, 1989. The catalogued events
were defined as observable changes in coronal structure occurring on a
time-scale between a few minutes and several hours, involves the appearance of
a new, discrete, bright, white-light feature which displays a predominantly
radial outward motion through the field of view. Detailed information on
individual events will be made available upon request by the Primary
Investigator, Dr. Hundhausen.

The NSSDC 80-014A-01B data set consists of 35 mm images of the solar corona on
100-ft. reels, made by transferring the digital output of the C/P vidicon array
(levels from 0-255) to film with a Dicomed recorder. Two of the instrument's
filters were used to make the digital images, a green broadband filter
(5000-5305A) and an H-alpha filter (6543-6583A). Pairs of sequential images
made with each of these two filters are found in chronological order on the
reels. In using this set, reference should be made to the following user's
guide documents: 'Guide to 1980 SMM Coronograph/Polarimeter 35 mm Images'; 'C
Data Analysis Guide.'