09 June 2023 - Mission Day: 10052 - DOY: 160
Science Operations


FOR YOUR INFORMATION. As SOHO operations resources are being reduced and
the mission is entering the lower-level phase (transition planned for
2010), the need and usefulness of the Science Planning Working Group (SPWG)
meetings has diminished. It was hence decided to discontinue the SPWG
meetings and this meeting was the last. The needs for SPWG type information
dissemination will be met primarily via the SOHO calendar
(http://sohowww.nascom.nasa.gov/soc/head_calendar.html) supplemented by
other contacts and meetings on an as-needed basis.

The usefulness of the SOHO calendar to users of the information can be
enhanced by joining the SOHO-CALENDAR-UPDATES mailing list. This list is
used to disseminate notifications of select calendar changes. To subscribe
contact the SOCs by e-mail.

1. Boundary conditions

a) Orbit, attitude and manoeuvres

- SOHO is upside down (180 degrees).

- manoeuvres

  To the degree possible, manoeuvres take place during the last days of
  34-m keyholes.  Currently proposed or set manoeuvre dates are:

  Feb 2 (TBC)      station-keeping and momentum management

  Feb 5 (TBC)      roll (to approximately 0 degrees)

  Apr 30 (TBC)     station-keeping, momentum management and 
                   roll (to approximately 180 degrees)

b) Communications with the spacecraft

  Graphical DSN schedule: http://soho.nascom.nasa.gov/soc/dsn/

  The SOHO High-Gain Antenna (HGA) was moved on Aug 14, 2009 to change the
  Z-axis angle from -18.55 to -16.7 degrees (to reduce keyhole
  durations). The keyhole durations will be 6-7 days shorter for the short
  keyholes (summer and winter seasons) and 10-12 days for the long

  Keyhole dates for the next 6 months:

* Jan 21-Feb 7  26m Keyhole
* Jan 26-Feb 3  34m Keyhole

* Apr 22-May 3  26m Keyhole
* Apr 24-May 1  34m Keyhole

  All keyhole information is available at or via

- End-of-pass handling during MDI continuous contact periods

  To avoid problems with transmitter masks at the end of passes during MDI
  continuous, DSN has requested we bring the carrier down 30 min before the
  end of pass.  As a result, the last 30 min of all MDI continuous contacts
  will be TM only.  For ranging passes, the spacecraft will be transitioned
  to record ~1 h before the end of the pass.  The station will drop the
  carrier and re-sweep into receiver 2.  The spacecraft will then be
  transitioned back to VC2 and VC3.

- DSN 26 m antenna decommissioning and the keyholes

  DSN decommissioned its 26 m antennae in early August. On 14 August, the
  SOHO HGA Z-axis was successfully moved from -18.55 to -16.7 degrees to 
  reduce keyhole durations.

c) KNOWN submode (SM) dependent activities/submode changes:

* TOO           JOP153/MMOP003 Future Major Flare Watch (SM5 if SUMER
                observes target, SM6 otherwise)
* Jan 7, 14     EIT shutterless #38
* Apr 8, 15     EIT shutterless #39 (time TBC)    
* Jul 8, 15     EIT shutterless #40 (time TBC)

  SUMER campaign dates may overlap with keyholes. Such overlaps shall be
  scheduled only if periods of no SUMER data between passes are acceptable.

  Except for Major Flare Watches, TRACE will be doing full disk mosaics
  if/when EIT is not able to do synoptic sets due to keyhole operations.

d) Instrument maintenance activities

e) Spacecraft maintenance activities

  The available power from the solar arrays is decreasing. Currently we
  still have sufficient margin, but in the future the decrease per year
  (now ca. 1 A) may increase to 3 A per year.  We have to be prepared to
  reduce our power needs as much as possible. On the spacecraft side
  several adjustments have already been made and there is not much more
  that can be done.  Therefore we are asking the instrument teams,
  especially the 'big' power consumers LASCO/EIT, CDS, UVCS and SUMER, to
  start looking into ways of reducing their power consumption
  (e.g. different operating modes, heater reductions, ...).  Hopefully we
  will not have to use this reduced power mode very soon, but it is better
  to be prepared in case a power reduction is needed.  More details coming

f) Others

  TRACE eclipse season began on Sep 13, 2008 and will be ongoing. Hard eclipses 
  started on Sep 13, 2009.

  Daytime weekday passes are automated but attended. For proficiency
  reasons FOT runs a crewed pass approximately once per week.

  NRT during automated passes (both weekend and weekday) is currently
  paused (briefly) regularly for resets of software anomalies. NRT schedule
  (which includes the pauses) for all automated passes can be found at

  New intermittent recording patch subsets needed during the Bogart mission
  phase will need to be tested on-board, which results in MDI data
  gaps. The testing is suggested to be made after Solar Dynamics
  Observatory (SDO) has been launched successfully.

  MDI: The testing of new patch subsets should not be done during
  the 60 day overlap between MDI and SDO/HMI next year.  That may mean that
  the testing for the patch subset changes will have to occur before or
  after May-July 2010.

2. Priorities for the coming month and more

a) Joint observing plans and campaigns

Continuing campaigns:

* 2002/02/25--  JOP136 Default RHESSI Collaborations (#6850),
                POC: Tero Siili
* 2003/05/13--  Default CDS Co-observations with TRACE (#6950)
* 2005/09/20--  JOP153/MMOP003 Future Major Flare Watch (#8008)
* 2007/03/20--  Default CDS/Hinode-EIS co-observations (#7200)

  Campaign #6850 is for "individual instrument studies" selecting an active
  region target [partially] influenced by the Max Millennium target
  selection to maximise chances of serendipitous co-observations.

  EIT supports all with half/full-res 195 A CME watch in submode 5/6. It is
  clear that STEREO-EUVI provides adequate "context" information for RHESSI
  flare observations. Routine EIT submode and resolution switches are
  probably no longer needed.

* Mar 16 - Sep  LASCO C2pB for Tomography Reconstruction,
                  POC: Angelos Vourlidas, Richard Frazin

* Mar 27-       JOP 222 (ToO) Detecting the Origin of Shock-Accelerated Solar
                  Energetic Particles, LASCO/STEREO-SECCHI
                  POC: Angelos Vourlidas

* Jan 11-17     JOP 225 STEREO/SOHO joint plume campaign, 
		  POC: Frédéric Auchère, Antoine Llebaria

  The dates remain TBC. In addition to the standard sequances, EUVI will
  take images approximately evry 30 min with a low compression ratio. EIT
  will support with a 171 CME wtach. COR and LASCO contributions are being

* Jan 7 (TBD)   EIT shutterless #38 run 1
                  POC: David Berghmans

  Runtime:  19:00-22:00 UT

* Jan 14 (TBD)  EIT shutterless #38 run 2
                  POC: David Berghmans

  Runtime: 19:00-22:00 UT

* Feb 3 (TBC)   Solar Dynamics Observatory (SDO) launch

  For launch date updates see
  http://www.nasa.gov/missions/highlights/schedule.html.  The commissioning
  phase is planned to last 60 days and hence end in early April, 2010

* Feb 26-28     MDI continuous contact

* Mar TBD       MDI continuous contact

  Duration 3-5 days.

* Apr TBD       MDI continuous contact

  Duration 3-5 days.

* May 4-Jul 17  MDI 60-day continuous contact, MDI/SDO

  Contingent on timely SDO launch and commissioning.

b) Intercalibration activities

  Last ICAL was: November 19

  ICALs are normally performed monthly. Below is a SOC proposal for ICAL
  weeks for the next six months. Baseline will be to schedule it for
  Thursday during contact.

* Nov 16-20     ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)

* Dec 14-18     ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)

* Jan 11-15     ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)

* Feb 15-19     ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)

* Mar 15-19     ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)
* Apr 12-16     ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)

* May 3-7       ICAL01 (#7113), CDS/EIT/STEREO/Hinode-EIS(TBD)/Hinode-SOT(TBD)

  Proposed compiled ICAL scheduling criteria, constraints and guidelines
  (see also campaign #7113):

  1) EIT/CDS are the primary participating instruments

  2) STEREO-EUVI observations are included when possible. ICALs are
     attempted to be scheduled not to coincide with STEREO manoeuvres or
     other interruptions in observations (see

  3) EIT: ICALs OK at all other times except the weeks of shutterless

  4) Dates, details and confirmation will be determined by the planners
     with support from the SOHO SOCs.

  5) Neither Hinode-SOT nor Hinode-XRT have current interest in
     participating in ICALs. Hinode-EIS will from time-to-time perform its
     sensitivity calibration exercise, but has no need to perform this
     regularly as part of the SOHO ICAL. Hinode teams will informed of
     ICAL01 dates as soon as they have been fixed by EIT and CDS. Hinde
     teams will then decide whether to participate.

c) Individual instrument plans


  See section 2a for MDI continuous contact periods.

  MDI may reduce the ALT cadence during Keyholes to be less than 15 ALT
  magnetograms per day if the lack of high rate telemetry is such that we
  will lose all or almost all of the 15 ALT Magnetograms each day.  The ALT
  cadence will be decided on an individual Keyhole basis and even a daily
  basis during each Keyhole depending on the 70 m antenna availability at
  the time.  MDI may also down-link select magnetograms in the 5 kbps
  telemetry if no 70 m passes are available at least every 2 days for Mag
  dump in the 160 kbps telemetry.

  All requests for MDI support need to be made several months ahead of time
  and sent to mdi-ops(at)mdisas.nascom.nasa.gov.  Even outside keyholes,
  MDI can only do 1-minute cadence observations when we have contact and
  there is no recorder dump in progress.

  MDI's REQUEST page is at http://mdisas.nascom.nasa.gov/coordination.html
  NOTE: Listing of a study on that page means *only* that a request has
  been received, not that it will necessarily be supported.

  A description of MDI Observing Modes most used for JOPs and campaigns (FD
  vs. HR) can be found at http://mdisas.nascom.nasa.gov/Collaborate.
  Anyone requesting MDI observations is encouraged to read this page in
  order to have a better idea of what observing modes would be best suited
  for a particular study.  More detailed information about how MDI
  operates, observational constraints and telemetry information can be
  found at http://mdisas.nascom.nasa.gov/MDI_Collaboration_Details.

  MDI has switched to Focus 5 (best focus for full-disk observing) on Oct
  23, 2008.

  MDI reserves the March 2010 continuous contact (dates TBD) for FD
  Helioseimology studies with Hinode-SOT.


  For weekly plans, see the SOHO calendar and the UVCS planning page:


  For details see http://solar.bnsc.rl.ac.uk/scientificops/request.shtml.


  EIT: 195 A CME watch plus synoptics at 6-hour cadence, as usual. Full-res
  CME watch whenever we're in submode 6. Hope never to change until the
  Bogart mission.


  The detector checkout on 8-9 Nov has shown that the central KBr coated
  section of detector B has suffered a dramatic loss of gain, and that only
  the "bare" side parts of the detector remain usable. The SUMER team
  believes that the detector can be stabilized if operated at reduced high
  voltage level.  Under these conditions science operations are still
  possible.  Observing programs will have to be revised and adapted to the
  new configuration.

  SUMER does not plan any operations before SDO commissioning.


  NOTE that TRACE in general reserves the right to withdraw support from
  agreed, existing collaborations if a sufficiently "good active region" is
  called by the Max Millennium group.

  For TRACE summer eclipse season see section 1f.

3. Any other business

The rest are FYI items:

* In the future SOHO's DSN contacts will grow shorter as we lose 26-m
  antenna support and other, new missions get higher priority. The
  instrument teams are therefore requested to look at the NRT commanding
  that is done (especially for emergencies and recoveries) and see what can
  be converted into TSTOLs that the FOT can run (even without explicit
  instrument or SOC direction).

* MDI high-rate support requests: no change, see URL

* DSN support requests: preferably at least 6 months in advance.  Keep this
  in mind for: ground-based collaborations that require MDI support,
  stellar/shutterless observations that require NRT, etc.

* Future Mercury and Venus transits: no change, see URL

* Hinode operational and planning information and guidelines: no change,
  see URL http://sohowww.nascom.nasa.gov/operations/SPWG/spwg-20080118.html
  and http://sohowww.nascom.nasa.gov/soc/JOPs/jop-submit.html

* STEREO operational and planning information: no change, see URL

* The SOHO JOP/ICAL database and the web pages are now the Solar JOP/ICAL
  database and web pages. This is due to anticipated increased
  contributions by and collaborations as well as intercalibrations with
  STEREO and Hinode.

* New JOP vs. modified existing JOP rules-of-thumb: no change, see URL

* SOHO calendar email notifications: no change, see URL

• European Site • US Site


Feedback & Comments: SOHO Webmaster

Last modification: July 27, 2020

SOHO is a project of international cooperation between