SOHO SPWG Minutes - April 1996
April 19, 1996, SOHO EAF, GSFC
Chair: Piet Martens
Notes: Laura Allen and Eliane Larduinat
V. Domingo, B. Fleck, A. Gabriel, K. Bocchialini, M. Huber,
J.-P. Delaboudiniere, B. Schmieder, P Lemaire, D. Spadaro, J. Raymond,
K. Dere, B. Kliem, B. Thompson, J. Newmark, J. Saba, R. Kavanagh,
J. Behuncik, A. Galvin, O. Kjeldseth-Moe, R.D. Bentley, D. Muhonen,
L. Allen, C. Froehlich, L. Sanchez, E. Larduinat, A. Poland,
P. Martens, J.-L. Bertaux.
- Review of Action Items
- Status update
- The coming month:
- Boundary conditions
- Priorities + outline
- Individual instrument plans
- Calibration plans
- Joint plans
- Plans for 2 months continuous
- Roll off-set
- MDI jitter test during momentum management
- JOPs status and priorities
- New JOPs
- Experiment anomaly reporting
- Publication of SOHO schedules
- Summary data
- As-run data-base
- Status of data distribution
- Special issue: First results from SOHO
- Daily meeting reports
- Inclusion of informal science workshops with the SWTs
- SPWG 4.1:
- Piet Martens to discuss duty cycle adjustments with Maryse Hervieux,
and report back on future plans to SPWG.
- SPWG 4.2:
- On Piet Martens to finalize and coordinate roll
maneuver timeline with FOT.
- SPWG 4.3:
- On the Project Scientist to request officially from MDI PI to perform
jitter tests for each momentum management as Matra has requested this
information to do trending on the reaction wheels
- SPWG 4.4:
- Luis Sanchez to hold meeting with instrument reps to discuss as-run
database, summary data, and populating archive
1a. Reviewing action items from last meeting
- SPWG 3.1:
- SPWG 3.2:
- On-going, now SPWG 4.2
- SPWG 3.3:
- For SWT
- SPWG 3.4:
- Plans for ECS to send summary data to CDHF for CD-ROMs.
Summary data does not need to be calibrated. Only EIT has given
summary data to date. VIRGO is going to check with Antonio for
summary data. MDI will supply magnetograms. UVCS will supply by
end of April. SUMER and CDS placing rasters -- no concrete plans
for data delivery.
- SPWG 3.5:
- On-going, now SPWG 4.3
2. Status Update
- Accumulating long data set for the last 2 - 3 weeks.
Been working in a mode (no polarizers) in the blue wing of light.
This will enhance the data, there will be no losses due to mechanism
problems. Not sure what is wrong concerning the mechanisms; but
will continue in this manner for a while
- Working -- lots of good results. Want to see how measurements
made in different directions (N,S,E,W) compare.
Spacecraft Heater Discussion
At the beginning of the week brought heaters to 50 % . (PTCS Adjustment)
VIRGO asked why were the heaters so abruptly changed from 100% to 50% ?
Especially when seasonal differences account for only a 3% change...
VIRGO thought that 100% was the range of the mission.
From here on, to correct for seasonal changes, duty cycle will be adjusted
in 10% steps, if needed, every 8 weeks during maneuvers.
- Continuous structure program. Uploading flat field tables by
background queue, had some interference with NRT commanding
instrument-wise so they stopped. Dynamics campaign will be getting
high rate data. Lot of Helioseismology data taken.
Showed magnetogram of active region taken on March 13.
Showed image taken in continuum.
Think of a better way to coordinate with coronal instruments to
- Working well. Noticed sensitivity decline of detector to high counts.
There was a 30% change in a reference spectra but this is being
corrected for. Think this is due to the microchannel plate. May
change to other detector in July. However, with this change there
will be a gain of 20% in efficiency. SUMER is trying to avoid active
regions -- trying to select lines to study that have ~ 10 counts /sec.
Permits long deep exposures in the corona at 1.5 Solar Radii
- Galactic Map of Lyman-alpha shown; Solar wind higher in Southern
than in the Northern Hemisphere; but depends on calibration between
the 2 sensors. Overall sky brightness has been increasing since
December, however still need to determine if this is real or detector
effect. Also problem that Lyman-alpha intensity plagued by Milky Way
stars/diffuse light. In Northern Hemisphere have Barium Fluoride
window that excludes Lyman-alpha; but there is no pixel like this
on the Southern detector. One way to discrimate is if the pattern
of stray light is the same after the roll..
Despite Sun shade, see a lot of light.. stray? coronal emission?
SWAN's main objectives during a S/C roll are:
- Check cross calibration of the 2 SWAN sensors
- Near Sun observations: Discrimate Stray Light from genuine
coronal Lyman-alpha emission.
- Subtract from Total Emission what has been recorded from
- Monitoring of Comets Infalling on the star Beta Pictorus
Put Barium Fluoride pixel on the star and stay there for some
time (~ one event per day)
Thinks instrument is aging. Full sky map takes ~ 22 hours.
There was a lot of discussion about whether or not to rotate the
spacecraft as SWAN wants to. EIT had nothing against the rotation.
VIRGO and MDI strongly opposed it stating that during the
Commissioning phase this would have been okay, but now we are
in the observational period and the main goal is to provide
CONTINUITY of the observations. VIRGO can't compensate for the
rolls. Data of the LOI cannot be used during the roll. Same
for MDI. MDI wants only minutes of interruption -- the timing
is especially bad with the two months of continuous contact
being so close -- MDI has only 3 chances to do this.
Coronal instruments would have to close doors. CDS reconfiguration
takes 2 days. Art Poland suggested since we have not gotten a
smooth flow yet planning these operations we should wait.
Discussion also involves JOP002, which requires + or - 90 degrees
roll. Requirement: slit of 2 spectrometers, only a polar hole
will have extent and depth to permit this. Desirable to do this
soon, closer to solar minimum. Choice of North or South pole based
on previous days' observations.
Requirement: turn 90 degrees and stay there for the sequence.
at first scheduled for 13 hours, then made to 17 hours. We now
want the duration to get back to the original 13 hours, to
limit total duration to 16 hours
AGREEMENT: If tests of JOP002 in the upcoming weeks go well, then
run JOP002 on May 20, as per the timeline draft of SOC. If tests
do not run well, then run JOP002 in July. Total duration, including
roll maneuvers not to exceed 16 hours. Exercise may be repeated in
September, or later, if needed, but this can be discussed/decided
in the upcoming SWT. Piet Martens to finalize timeline with FOT to
have them arrange for DSN backups, etc.
- Nominal. Campaigns: flows, bursts, jets, XBP
Found high velocity events. GIS shows some
degradation at 304 line
and needed to adjust the voltage. It is not unexpected since it is
such a strong line they expected problems.
- Nominal. Considers itself still in commissioning phase due to S/W.
New OBE load for LASCO software. Still no planning tool yet.
EIT is happy with the repointing, no need for extra aluminum filter.
Do not plan on using different telemetry submodes soon, their S/W
can't handle it yet.
- Synoptic observations (taking 55% of the time), running sequences
devoted to line profiles, solar wind velocities, optimized
sequence of commands for JOP002. No results yet from temperature
and line profiles. UVCS sees most of lines they expected to see.
UVCS sees more lines than they originally thought.
- Waiting for energetic particle event for STOF. Getting data at
low levels. Still commissioning, got flight software patches.
- Failure 6 weeks ago with first telescope. Second telescope has
higher noise. Nominal, operating and taking data now.
3. Coming month
XBP Campaign needed better coordination with DSN schedule
In future, asking for 3 weeks ahead notice for planning future
campaigns such as XBP.
Request was made to be better informed of project database updates and
when they are scheduled.
Plans for 2 months continuous
Information on collaborations with Ground-based observatories, coordination
contacts, etc. should be forwarded to SOC for inclusion into the schedule.
MDI will have no high resolution observations, just full disk magnetograms
every 96 minutes.
On June 10th, Venus passes in front of the solar corona, not the disk.
MDI jitter test during momentum management. Monitor jitter performance
of wheels but have not received a formal request to do this. (action on
VD). Found the amplitude of the resonances to be between 0.001 - 0.02
arcseconds. MDI wants this done in very close proximity and is currently
performing this before and after the movement (but not during..).
4. JOPs and Priorities
The following JOP schedule was determined at the meeting.
See the SOHO Web pages for updates to the schedule!
For latest updates on JOP descriptions, see also the SOHO
Web pages: (http://sohowww.nascom.nasa.gov/operations/JOPs/).
UPDATE: April 22, 1996
M Apr 22 (W17)
T Apr 23
W Apr 24 START MDI Continuous, JOP002 (test only no rolls -- 3 hours)
T Apr 25 JOP002 (contingency), JOP020: Nanoflares
F Apr 26 JOP028 (4 hours); JOP012 6:00-12:00 UT SUMER Prominences (test)
S Apr 27 Intercal 002, phase 2
S Apr 28 END MDI Continuous
M Apr 29 (W18) JOP035 (depending on opportunity)
T Apr 30 JOP013 (TBC) LASCO/SWAN start Comet Observation
W May 01 JOP012 Prominences (test) or filaments
T May 02 JOP015 (during NRT)
F May 03 JOP002 (test; no rolls)
S May 04
S May 05
M May 06 (W19) LASCO end Comet Observations
T May 07
W May 08
T May 09 JOP015
F May 10 Special ISTP configuration (WIND, Geotail)
S May 11
S May 12
M May 13 (W20)
T May 14 JOP022 (TBC)
W May 15
T May 16 JOP027 (TBC)
F May 17 Momentum management -- some experiments close doors
S May 18 Experiments reopen doors, CDS reconfigure
S May 19 Normal operations, CDS reconfigure
M May 20 (W21) S/C 90 degrees roll (JOP 002, SWAN galactic map; 16 hours max)
T May 21 Second momentum management (if needed)
Orbit correction burn
Third momentum management (if needed)
W May 22 Contingency, experiments reopen doors
T May 23
F May 24 Start of 2 Months Continuous
S May 25
S May 26 Star calibration (SUMER/UVCS)
M May 27 (W22)
T May 28 JOP031 (streamers) (TBC. Could be delayed)
W May 29 JOP031
T May 30 JOP031
F May 31
S Jun 1
S Jun 2
Are there any other JOPs in which Yokhoh participation is desired?
JOP leaders should coordinate with them. Bob Bentley volunteers for this.
A schedule for Intercalibration JOPs will be determined by the SICWG.
5. New JOPs
JOPS updated on the Web. Intercal2 has been updated.
No new JOPs proposed in last week.
Phil Judge and Olav (CDS) are working on a JOP that will entail looking at the
dynamics in specific Helium lines. This will be submitted soon.
6. Experiment anomaly reports
Continue with these? Leave as item for SWT.
7. Publication of SOHO schedules
Purpose of SOHO planning tools is to exchange information between SOHO
experiments, and to announce to the world the observing programs and
targets of the SOHO experiments. SOHO Web pages exist that make the
information from experiment IAPs accessible, but so far IAPs are not
updated frequently enough to reflect the actual observing program,
and neither do they contain information on observing targets and
The reason appears to be that the planning system of experimenters are
not yet fully functional. B. Bentley said coordinates may be in IAPs,
but not passed on to KAPs.
IAP updates: CDS keeps track of updated schedule via command uploading.
The ICD states coronal instruments only need to input coordinates, not
EIT has no planning tool, typing all in by hand. EIT planning tool cannot
talk to LASCO.
UVCS is typing in things by hand. Going from sciplan, no coordinates.
Experiments and Project Scientist teams will work together to improve
8. 9. As-run database
As-run database is unclear among various teams. Luis will make it an action
item to sit down with teams next week to organize this.
10. Status Data Distribution
CD-ROMs will be generated from JPL tapes with the nasty gaps removed.
On Wednesday after the Daily Meeting, Luis will have a meeting about this.
SWAN LOBT not always correct. Time stamp is in the data but wrong by 2 months.
Real spacecraft time not on science packet. SWAN may have trouble organizing
data with incorrect time stamps.
11. Special Issue: First Results from SOHO
Bernhard Fleck brought up an issue to be talked about once more at the SWT.
This concerns having a joint SOHO issue in Solar Physics with early results.
Discussed latest proposal of Zdenek Svestka which foresees a split of the
SOHO special in 2 or 3 parts. Part I should appear in the Nov issue
of Solar Physics, Part II in the January or February 97 issue. After some
discussion this split solution was considered a reasonable compromise,
rather than delaying the whole issue until 1997.
It was decided to continue having minutes of daily meetings made and
distributed per subscription mailing list.
Horst Kunow suggested that an informal science workshop be held near
the SWT so that the particle experiments could learn more about the
science that other instruments were doing. For example, 1/2 day for a
meeting then another 1/2 day of discussion. This workshop should have
contributions from all scientists not just the PIs and be held around
the SWT in time frame. Finally it was agreed to start with a 1/2 day
workshop at the May SWT meeting (afternoon of May 16). H. Kunow
volunteered to organize it.