SOT Initial Operation in Commissioning Phase

1
SOT Initial Operation in Commissioning Phase

• Y. Katsukawa (NAOJ)
• SOT team

2
SOT initial operation overview
3
(I) Spacecraft verification and checkout phase

• Period Launch ? Y20
• Orbit control maneuvers are carried out several
  times to install the S/C to the sun-synchronous
  orbit.
• Check-out of S/C attitude control system is also
  performed during this period.

4
(I) Spacecraft verification and checkout phase
5
(I) Spacecraft verification and checkout phase

• After ?a1 (Y6), the altitude of S/C becomes
  high enough, and the attitude of S/C is
  controlled by MWs.
• During the period between Y7 and Y20, we plan
  to do initial status check (temperatures) and CCD
  heater operation.
• Primary objective is to decontaminate the CCDs.

?a2
MDP and FPP ON
CCD decontamination heater ON
3days
1.5 days
CCD decontamination heater OFF
FPP and MDP OFF
?a3
6
(II) SOT instrument checkout phase (1)

• Period Y21 ? Y28 (TBD) (?1 week)
• From the installation to the sun-synchronous
  polar orbit
• To opening the SOT top door
• The primary objectives are (1) decontamination of
  M1, M2, and HDM, and (2) initial functional
  checkout without sunlight into the telescope.
• The test items of this phases are the following
• Verify function of operational heaters for OTA
  and FPP
• Open the telescope side door
• Decontamination of M1, M2, and HDM
• Verify function of mechanisms (shutters, filter
  wheels etc.)
• FG, SP, and CT image acquisition
• Automatic observation by MDP table control
• Obtaining dark images is also important items
  especially for SP because there is no shutter in
  the SP optical path.

7
(II) SOT instrument checkout phase (1)
8
(II) SOT instrument checkout phase (1)

• Obtaining dark images
• Obtain the images with some camera setting
  (gain, amplifier)
• Orbital variation, temperature dependence
• Effect of cosmic radiation on the images
• All the data taken during this period is to be
  down-linked at the Uchinoura station (USC).
• Some of them will be down-linked at the Svalvard
  station (SVA) in order to test data transfer
  system from SVA to Japan.

9
(III) SOT instrument checkout phase (2)

• Period Y30 ? Y45 (TBD) (?2 weeks)
• First light phase after the telescope door is
  opened
• The primary purpose of this period is
  verification of optical performance
• Alignment with respect to sun-sensor, XRT, and
  EIS
• Image quality and focus stability
• Correlation tracker performance
• Function of FG and SP observables, etc.
• In-flight calibration of the instruments
• Darks and flat fields
• Polarization
• TF wavelength tuning etc.

10
(III) SOT instrument checkout phase (2)
11
(III) SOT instrument checkout phase (2)
12
(1) Top-door opening / Initial optical check

• One of the most critical event in the initial
  operation
• Make the satellite pointing to the disk center
• Light level is continuously monitored by CT live
  images when the door opening operation.
• After the top-door is successfully opened, we
  plan to switch observation tables to carry out
  the initial optical checkout.
• Light level check for FG (all the wavelengths),
  SP, and CT
• SP 6301.5/6302.5 spectrum line positions and
  profiles
• Alignment check to the sun-sensor (chromospheric
  features may provide pointing information even in
  QS)
• Quick focus scan and adjustment are planned to be
  done in real-time operation half a day after the
  door operation.

13
(2) Background observations during the operation
of the other telescopes

• SOT commanding operation cannot be done during
  the door opening operation of the other
  telescopes.
• We plan to run some observation tables in
  background with low cadence in order to verify
  the following items.
• Data transfer from Svalvard station
• Image compression efficiency
• Dark images, flat fielding (by averaging many
  images)
• Camera noise (light transfer measurement)
• Alignment with respect to XRT and EIS
• CT diagnostic data to get S/C jitter information
• SP full FOV scanning (to check vignetting and
  alignment)
• BFI observations (e.g. G-band) with shorter
  exposure can be possibly carried out without
  correlation tracker. Such observations with
  longer duration may provide information on
  orbital variation of image quality.

14
(3) Correlation tracker servo-on / Detailed
verification of optical performance

• After CT servo is turned on, we can go to
  detailed verification and calibration of optical
  performance.
• Fine focus scan
• Image quality evaluation
• Co-focus among different channels
• Adjust focus position if necessary
• Continuous observations for several hours with a
  few wavelengths
• Orbital variation of image quality
• Inter-channel alignment
• Image quality degradation by disturbance from
  FPP, XRT and EIS
• Flat fielding
• Flat fielding by intentionally move the tip-tilt
  mirror
• Tunable filter (TF) wavelength scan/ NFI
  observables
• TF spectroscopic performance
• Update tuning parameters if necessary
• Verification of MDP Doppler velocity compensation

15
(4) Limb observation

• After optical performance verification is done
  near the disk center, we like to go to limb
  observation.
• The verification items in the limb observation
  are
• S/C pointing check
• Image quality and focus change between DC obs and
  limb obs
• Scattered light
• TF wavelength tuning, MDP Doppler compensation
• Function of the correlation tracker in limb obs.

16
Pointing and target selection in the first light
phase

• We have to know misalignment with respect to the
  sun sensor (ACS), XRT, and EIS as fast as
  possible for the secure operation.
• After the satellite pointing is established, we
  like to track a suitable active region near the
  disk center if we have for verification of the
  optical performance (as well as scientific
  interest).
• When the verification near the disk center is
  done, the limb observation is necessary to verify
  performance of SOT at the limb. We may go to the
  limb observation automatically by tracking an
  active region in the first light phase.
• After the limb observation, we can make SOT
  pointing to any region.

17
(IV) Performance verification (PV) phase

• Period Y46 ? Y60 (TBD) (?2 weeks)
• After the first light phase
• The primary purpose in this phase is verification
  of scientific performance of the SOT observables
• Background
• SOT has a capability to observe various
  scientific targets.
• Wavelength coverage
• BFI 6 channels, NFI 6 channels, and SP 6302A
• Many types of observables
• Single image, LOS magnetograms, Stokes IQUV, and
  Dopplergrams
• Temporal and spatial sampling
• Knowledge obtained in this phase shall be used
  for following scientific operation.

18
(IV) Performance verification (PV) phase

• Phase-I
• At first, we verify performance of high-priority
  observables with a typical wavelength to verify
  basic scientific performance of SOT
• Only one observable or simple combination are
  used for long duration (several hours ? half a
  day).
• SP observations can be carried out simultaneous
  with FG.
• Phase-II
• After the verification of each observable is
  completed, we make combined observations with
  multiple wavelengths and observables.
• SP observations can be carried out simultaneous
  with FG.

19
(IV) PV Phase-I

• Make observations with some observables with
  typical wavelength for long duration to verify
  long-term stability.
• Some of them can be carried out in the first
  light phase as background observation

Examples of FG observation sequences
20
(IV) PV Phase-I
Examples of SP observation sequences

• Some FG observables, especially magnetograms and
  Dopplergrams, shall be carried out simultaneous
  with SP in order check their performance.

21
(IV) PV Phase-II

• Make combined observations with multiple
  wavelengths and observables.

Examples of FG observation sequences (multiple
wavelength combination)
22
Target region selection in PV phase

• In general, we track one active region for
  several days - one week.
• When there is no active region on the sun, we
  observe quiet regions, dark filaments etc. with
  science priority.