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Summary
General information:

Principle Investigator for the WHITE-LIGHT CORONAGRAPH experiment was
Dr. R. Macqueen, U of Colorado, Boulder, CO

This experiment, located in the Apollo Telescope Mount (ATM) on
SKYLAB, used an externally occulted coronagraph to monitor (between
4000 and 6000 A) the brightness, form, and polarization of the solar
corona ... at radial distances between 1.5 and 6.0 solar radii. The net
angular resolution was 8.2 arc seconds (corresponding to 6000 km in
the corona). A solar disk illuminated step wedge, covering the
intensity range of 10E-8 to 10E-10 solar radiances, was imaged on each
picture frame by a supplementary optical system. Instrumentally
scattered light was reduced to the order of 10E-10 mean solar
radiances.

The main body of data was recorded on Kodak special film 026-02, while
a television system provided backup capabilities. Polarization data
were obtained using a polarization wheel assembly that contained a
clear (open) aperture and three polaroid apertures with polarization
planes displaced about 120 deg from each other.

Four separate operating modes were used: a standard patrol mode,
providing three exposures durations (3, 9, and 27 s) at four different
polaroid wheel positions, expending 12 frames over 5.5 min; an
extended standard patrol mode, which repeated the standard patrol mode
for three times and took 16.2 min; a continuous patrol mode, which
took one exposure every 27.5 s, sequencing through 9-, 27-, and 3-s
exposures with the filter wheel locked in the clear position; and the
fast scan mode, which took 72 frames in 16.2 min, sequencing through
27-, 9-, and 3-s exposures with 0.5 s between exposures and the filter
wheel locked in the clear position. Each frame taken contains an
image of the solar corona and the occulting disk with out-of-focus
occulting disk pylon, intensity calibration pattern, four fiducial
marks, and a diode matrix array that contains operating mode, wheel
position, Sun-center pointing, instrument internal alignment,
spacecraft roll, and time-of-day information.

Although minor problems did occur (e.g., 0.5 percent of the frames
were overlapped due to an incomplete frame advance; a stalled film
transport motor resulting in a loss of photographic data from
days-of-year 161 to 170; occulting disk contamination by dust caused
blemishes in the images on two separate occasions lasting 6 and 27
days, etc.), five film loads of approximately 228.60 m (750 ft) each
were taken from the time of the first manned mission through the last
manned mission.

Datasets available:
-------------------

1. Fourth- (Pos.) and Fifth- (Neg.) Generation Copies of a Coronagraph
Photograph (NSSDC ID 73-027A-04A)

This data set is a complete set of all frames photographed on all
Skylab missions. Approximately 36,000 frames of data were taken, or
about 609.60 m (2,000 ft) of 35-mm black and white film. These frames
are in chronological order. The copy supplied to NSSDC was made by
contact printing the original 026-02 flight film using SO-355 film
with processing optimized for the 9-s clear exposure (i.e., no
polarizer in place). These data have a step wedge located in the
center of the occulting disk. These data are available as 35-mm
negative or positive copies or as enlargements on film or paper. For
enlargements on paper, the step wedge is usually covered.

Also Supplied:

'The High Altitude Observatory White-Light Coronagraph Experiment
For the Apollo Telescope Mount,' no author, July 1975

'The ATM Mission Operations Log'


2. Selected Flare Data, Set 1 (NSSDC ID 73-027A-04B)

This data set, contained on one roll of 35-mm black and white film,
includes only data relevant to the following five solar flares - July
29, 1973, at 1330 UT; August 9, 1973, at 1553 UT; September 5, 1973,
at 1834 UT; September 7, 1973, at 1203 UT; and January 21, 1974, at
2320 UT. The data include samples taken around 24, 18, 12, and 6 h
before the flare in question, all data taken from 1 h before through 2
h after the flare, and data samples taken at 6, 12, 18, and 24 h after
the flare. This is a subset of the previously mentioned dataset
(NSSDC ID 73-027A-04A), and was generated at NSSDC.

Also Supplied:

'The High Altitude Observatory White-Light Coronagraph for the
Apollo Telescope Mount,' no author, July 1975

'The Supporting Documentation for ATM Flare Subset Film (73-027A-04B)'

The High Altitude Observatory at the National Center for Atmospheric
Research maintains a digital version of the full data set above.
Interested users should contact Alice Lecinski, the Technical Contact,
to request data in digital form.

Data Set Citation

Dataset Creator: NASA/GSFC/NSSDC Dataset Title: White-light Coronagraph Images from the Skylab/ATM Online Resource: http://nssdc.gsfc.nasa.gov

Temporal Coverage

Start Date: 1973-05-28 Stop Date: 1974-02-08

Location Keywords

SPACE > SOLAR REGION > CORONA

Science Keywords

SUN-EARTH INTERACTIONS > SOLAR ACTIVITY > SOLAR FLARES SUN-EARTH INTERACTIONS > SOLAR ACTIVITY > SOLAR IMAGERY

ISO Topic Category

IMAGERY/BASE MAPS/EARTH COVER GEOSCIENTIFIC INFORMATION

Platform

SKYLAB

Instrument

CORONAGRAPHS

Ancillary Keywords

CME CORONAL MASS EJECTION IDN_NODE GSFC/NSSDC

Originating Center

NSSDC

Data Center

National Space Science Data Center, Space Science Data Operation Office, Goddard Space Flight Center, NASA Data Center URL: http://nssdc.gsfc.nasa.gov/ Dataset ID: 73-027A-04A Dataset ID: 73-027A-04B Data Center Personnel Name: NSSDC USER SUPPORT OFFICE Phone: (301) 286-6695 Fax: (301) 286-1635 Email: request at nssdca.gsfc.nasa.gov Contact Address: National Space Science Data Center NSSDC/Code 633.4 NASA/Goddard Space Flight Center City: Greenbelt Province or State: MD Postal Code: 20771 Country: USA

Personnel

DAVID ALLEN BATCHELOR Role: DIF AUTHOR Phone: 301-286-2988 Email: David.A.Batchelor at nasa.gov Contact Address: NASA Goddard Space Flight Center Code 561.0 City: Greenbelt Province or State: MD Postal Code: 20771 Country: USA ALICE LECINSKI Role: TECHNICAL CONTACT Phone: (303) 497-1523 Contact Address: High Altitude Observatory National Center for Atmospheric Research P. O. Box 3000 City: Boulder Province or State: CO Postal Code: 80307-3000 Country: USA ROBERT M. MACQUEEN Role: INVESTIGATOR Phone: (901) 726-3000 Contact Address: Rhodes College Physics Dept. 2000 N. Parkway City: Memphis Province or State: TN Postal Code: 38112-1726 Country: USA

Publications/References

Zirker, J. B., ed., Coronal Holes and High Speed Wind Streams (Boulder,
Colorado Univ. Assoc. Press), 1977.

Sturrock, P. A., ed. Solar Flares (Boulder, Colorado Univ. Assoc. Press),
1980.

Creation and Review Dates

Last DIF Revision Date: 2005-07-28

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