SOT Initial Operation in Commissioning Phase

1. SOT Initial Operation in Commissioning Phase Y. Katsukawa (NAOJ) SOT team SOT17 @ NAOJ

2. SOT initial operation overview SOT17 @ NAOJ

3. (I) Spacecraft verification and checkout phase • Period: Launch  Y+20 • 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. SOT17 @ NAOJ

4. (I) Spacecraft verification and checkout phase SOT17 @ NAOJ

5. (I) Spacecraft verification and checkout phase • After a#1 (Y+6), the altitude of S/C becomes high enough, and the attitude of S/C is controlled by MWs. • During the period between Y+7 and Y+20, we plan to do initial status check (temperatures) and CCD heater operation. • Primary objective is to decontaminate the CCDs. a#2 MDP and FPP ON CCD decontamination heater ON 3days 1.5 days CCD decontamination heater OFF FPP and MDP OFF a#3 SOT17 @ NAOJ

6. (II) SOT instrument checkout phase (1) • Period: Y+21  Y+28 (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. SOT17 @ NAOJ

7. (II) SOT instrument checkout phase (1) SOT17 @ NAOJ

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. SOT17 @ NAOJ

9. (III) SOT instrument checkout phase (2) • Period: Y+30  Y+45 (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. SOT17 @ NAOJ

10. (III) SOT instrument checkout phase (2) SOT17 @ NAOJ

11. (III) SOT instrument checkout phase (2) SOT17 @ NAOJ

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. SOT17 @ NAOJ

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. SOT17 @ NAOJ

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 SOT17 @ NAOJ

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. SOT17 @ NAOJ

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. SOT17 @ NAOJ

17. (IV) Performance verification (PV) phase • Period: Y+46  Y+60 (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. SOT17 @ NAOJ

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. SOT17 @ NAOJ