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NSO Summer Student Program (1Sep94)
(from NSO, NOAO Newsletter No. 39, 1 September 1994)

Scott Beardsley (University of Wisconsin) is assisting Thomas Rimmele in
analyzing time sequences of granulation images to evaluate algorithms that
have been proposed for tracking solar images. The algorithms to be compared
are 2-D cross-correlation using FFT's, sum of absolute difference and the
areal quad-cell approach. We also intend to simulate the use of a binary
ferro-electric liquid cristal device in an optical correlator and compare the
performance that can be expected from such a device with that of digital
approaches. The algorithms will be compared in terms of their performance in
different seeing conditions. In particular the performance when tracking
images of extremely low contrast will be examined.

Howard Beckley (Colorado School of Mines) is working with K.S.
Balasubramaniam and Steve Keil on calculating velocity and magnetic field
flows in solar active regions using data from the NSO/SP/VTT narrow band
filter (NBF) observations. The results of this research will lead to finding
drivers of active region energy build-up leading to solar flares.

Eric Burgh (University of Michigan) is assisting Matt Penn in a project to
study the Jupiter/Comet Shoemaker-Levy 9 encounter. The project will collect
three types of data; imaging data in the blue continuum, imaging data in two
near-infrared methane absorption lines and nearby continuum, and slit spectra
across the Jovian equator at 1.56 microns. Burgh is involved in all phases of
the experiment; he will be helping with the actual observations, reducing and
calibrating the data, and analyzing the data for scientific content.

Steve Doinidis (New Mexico State University) is working with Dick Dunn on the
development of the adaptive optics system at NSO/SP. He is determining both
analytically and experimentally the value of the weight tables that will be
loaded into the "Digital Reconstructor", which is a hardware matrix
multiplier that processes the data stream from the wavefront sensor. It
computes the offsets to the actuators on the adaptive mirror so that its
surface will fit the wavefront. For the experimental data he is using the
12-actuator mirror and the Dyson white-light interferometer that forms the
"test bed" for the project.

Sally Donaldson (1994 Tufts University graduate going to the University of
Maryland in the fall) is working with Frank Hill on the analysis of the GONG
site survey data from the six selected GONG sites, plus Tucson, Kitt Peak and
Sac Peak. She is also investigating the oscillations of the observed magnetic
fields, with a six hour time sequence, obtained at a one minute intervals,
with the GONG prototype instrument.

Dali Georgobiani (graduate student from Abastumani Observatory in Tbilisi,
Republic of Georgia) under the supervision of Jeff Kuhn has been developing a
model for solar scintillation during an eclipse, and applying it to data
obtained during the last annular eclipse. She is also computing the effects
of magnetic fields on heat flow in the solar interior using numerical MHD
models.

Leisa Glennie (University of Arizona) is working with Jack Harvey on the
reduction and analysis of daily full-disk images of the Sun. The images show
the Sun in a 10  band centered on the Ca II K line and are intended to help
identify the sources of solar irradiance variations. In addition to reduction
and archiving of the data, Glennie is experimenting with image restoration
algorithms to improve the photometric quality of the data.

Neil Jones (California Institute of Technology) is working with Doug Rabin on
the reduction and analysis of data from the Near Infrared Magnetograph (NIM).
This instrument probes the structure of intense magnetic flux tubes in the
deep solar photosphere through high-resolution spectropolarimetry of
Zeeman-sensitive Fe I lines near 1565 nm. The original design of NIM provided
only for circular polarimetry, from which the strength, but not the
direction, of the magnetic field can be inferred. Now that the instrument has
been augmented to measure all states of polarization, Jones is extending and
improving the software to make use of this new information.

Shella Keilholz (University of Missouri/Rolla) is working with Charlie
Lindsey and Doug Rabin on analysis of infrared CO-line occultation spectra
made at the McMath-Pierce Solar Telescope during the nearly annular solar
eclipse of May 10, 1994 over Kitt Peak. The observations were made in support
of a program by Alan Clark (University of Calgary) to determine the
distribution of CO line emission in the solar chromosphere. Shella has
developed software useful for general dark-current drift analysis and
compensation. She has also created utilities for recognizing defective pixels
based on distributions of various pixel parameters and is developing schemes
for correcting image defects due to defective pixels.

Stefan Ljungberg (Royal Institute of Technology, Sweden) is working with K.S.
Balasubramaniam and Steve Keil on NSO/SP/VTT data obtained during
observations of the 10 May 1994 eclipse to derive stray and scattered light
functions. Stray and scattered light functions influence the accuracy of the
measured velocity and magnetic field signatures. This project will estimate
the correction factors and in turn will help to derive accurate velocity and
magnetic field patterns for solar active region evolution analysis.

Ernie Nix, who teaches science at the Cloudcroft High School in Cloudcroft,
NM is working at Sacramento Peak with Steve Keil as part of the New Mexico
Science and Technology Education Program (STEP) for high school faculty. The
aim of the STEP program is to keep teachers current on research techniques
and objectives so they can in turn keep their courses current. Nix is working
on velocities and acceleration mechanisms in coronal mass ejections, using
data from the NSO/SP advanced reflecting coronagraph.

Sara O'Brien (University of Arizona) is working with Mark Giampapa to reduce
and analyze a time-series of high resolution, H-alpha spectra of young stars
and M dwarf stars (with unique chromospheric properties) as obtained with the
McMath-Pierce solar-stellar spectrograph. The line profiles will be studied
to determine if periodic variability is present. In addition, radial
velocities for a small sample of so-called "weak" T Tauri stars in the
Ophiuchus star formation region will be determined.

Reed Riddle (University of Arizona) is rereducing the 1987 South Pole data
under the direction of Stuart Jefferies. He has generated new flatfielding
and secondary image removal procedures which are better than those used in
the original reduction of this data. The new reduction will lead to a solar
oscillation power spectrum that has better signal-to-noise characteristics
and extends to higher spatial frequencies than our original spectrum of the
data. This will allow for a better comparison with our 1988 and 1990 data
sets in the search for solar cycle related changes in the solar oscillation
power spectrum.

Dennis Strelow (recent grad in computer sciences from the University of
Wisconsin) is working this summer with Don Neidig and Jack Zirker. They are
analyzing a 7-day time series of magnetograms and whitelight images of a spot
group, taken in 1990 at Big Bear Solar Observatory. The group shows some
remarkable shearing motions and Dennis will attempt to correlate these with
flare productivity in the group. Dennis will also work on some whitelight
flare data for correlation with gamma ray emissions.

Meredith Wills (Harvard University) is working with Harrison Jones on
comparing the full set (magnetic, velocity, continuum intensity, equivalent
width, and central line depth) of daily full-disk spectromagnetograph images
with spacecraft measurements of solar irradiance variations.

K. Balasubramaniam, Dick Dunn, Mark Giampapa, Jack Harvey, Frank Hill, Stuart
Jefferies, Harry Jones, Steve Keil, Jeff Kuhn, Charlie Lindsey, Don Neidig,
Matt Penn, Doug Rabin, Thomas Rimmele, Jack Zirker

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