• ► Instruments
• ► Operations
• ► Data
• - HTTP (Processed)
• - HTTP (Preliminary)
• ► Query
• ► Analysis
• ► Publications
• ► Links

HINODE Instruments - Solar Optical Telescope (SOT)

SOT has an unprecedented 0.2 arcsec resolution for the observation of solar magnetic fields. It would resolve a feature with the size of 50cm, if it observed the Earth.

Its aperture is 50cm and angular resolution achieved will be 0.2arcsec (175km on the Sun) covering a wavelength range of 388-668nm. SOT also includes the Focal Plane Package (FPP) vector magnetograph and spectrograph. SOT FPP contains three CCD cameras: Filtergraph (FG), Spectro-polarimeter (SP) and Correlation Tracker (CT).

For more details on SOT, check the following links:

• Hinode SOT instrument page at NAOJ
• Instrument Details page at LMSAL SOT website

---

SOT-FG

SOT-FG was an imaging instrument that created images of the solar photosphere and chromosphere in various wavelengths of light, however, due to a camera anomaly in February 2016, SOT-FG no longer operates. The two primary imaging modes of SOT-FG, The Broadband Filter Imager (BFI) and The Narrowband Filter Imager (NFI), sampled different fields of view, passbands, and spectral regimes.

The BFI consisted of six interference filters mounted in a user-controlled filter wheel. The filters have bandpasses of between 3 Å and 8 Å and produce high-resolution, low-exposure-time filtergrams.

BFI specifications

• Field of view : 218"×109"
• CCD detector size : 4,096×2,048 pixels (shared with NFI)
• Spatial samplingas : high as 0.0541" per pixel
• Typical exposure timeas : short as 0.03–0.8 s, but longer if desired
• On-board summing options : 1×1, 2×2, or 4×4
• Readout time : 3.4 s, 1.7 s, or 0.9 s, depending on summing (faster for partial-frame readouts)
• Reconfigure time : < 2.5 s (e.g., to change filters)

The NFI provides intensity, Dopplergram, magnetogram, and full Stokes polarimetric imaging at high spatial resolution in any one of 10 spectral lines. The NFI consists of a tunable Lyot filter with selectable bandpasses in six key solar spectral regions, which are determined by wide-band interference filters preceding the Lyot filter. The bandpass of the Lyot filter is narrow enough for taking magnetogram and Dopplergram measurements in a number of the available spectral lines. Additionally, the NFI can be operated synchronously with the polarization modulator of SOT in order to take Stokes I, Q, U, and V images.

NFI specifications

• Field of view : 328"×164" (unvignetted 264"×164")
• CCD detector size : 4,096×2,048 pixels (shared with BFI)
• Spatial sampling : as high as 0.08" per pixel
• Spectral resolution: 90 mÅ (0.009nm) at 6300 Å (630nm)
• Typical exposure time : as short as 0.1–1.6 s, but longer if desired
• On-board summing options : 1×1, 2×2, or 4×4
• Readout time : 3.4 s, 1.7 s, or 0.9 s, depending on summing (faster for partial-frame readouts)
• Reconfigure time : approximately 5 s (e.g., to tune the Lyot filter)

There are two methods of obtaining Stokes vector images from the NFI:

In shuttered mode

The NFI shutter is synchronized to the polarization modulator and gives precise 0.1 s exposures in all quadrant-phases of the rotation. The allowed frame sizes and pixel summing are the same as for the longitudinal magnetograms. A full complement of Stokes images takes about 20 s to capture in this mode.

In shutterless mode

The NFI shutter is left open and one of four focal plane masks is inserted in order to reduce the FOV down to a narrow vertical strip centered on the CCD chip. The CCD is then read out in synchrony with the polarization modulator, accumulating charge in the central strip and then shifting it under the focal mask. The smart memories add or subtract the strip images as they are received from the CCD to create the component Stokes images. The cadence of these observations ranges from 1.6 s to 12.8 s, and the sensitivity can be very high because of the long integration time. While the field of view is limited in this mode, the field of view can be increased at the expense of time resolution by reading out different strips on the CCD and combining them afterwards.

Filter configurations of BFI and NFI are summarized in the following table, which are adapted from Table 2 of Tsuneta et al. (2008).

More details are the SOT-FG Data Products page on LMSAL.

Go to top of this page ⏏

---

SOT-SP

The scanning slit-spectrograph of SOT-SP has a lot of flexibility in mapping a region of interest on the Sun. The instrument uses a 0.16″×164″ slit to scan a region of interest up to 320″ wide, but the multitude of options include whether to use on-board binning both in the scan direction and along the slit, whether to adjust the area to be scanned, and whether to repeat the scan automatically. The instrument also has the capability to vary the integration time at each slit position.

The most common observing modes are summarized in the following table, which is adapted from Table 3 of Tsuneta et al. (2008):

Observation Mode	Parameter	Value
Normal maps have the highest spatial resolution, but also use a slow scan rate and have high telemetry requirements.	Time per slit position FOV along slit Sampling along slit Polarimetric S/N Mapping Rate Full width scan time	4.8 s 164" (1,024 pixels) 0.16" 103 169 s per 5" scanned approx. 3 hours
Fast maps are binned 2×2 on board*, and represent a useful tradeoff between spatial resolution, scan frequency, and telemetry.	Time per slit position FOV along slit Sampling along slit Polarimetric S/N Mapping Rate Full width scan time	3.2 s 164" (512 pixels) 0.32" 103 64 s per 5" scanned approx. 70 minutes
Dynamics mode uses the highest spatial resolution but with a narrow scan width and reduced height, and continuously rasters the same (narrow) field of view.	Time per slit position FOV along slit Sampling along slit Polarimetric S/N Mapping Rate	1.6 s 32" (200 pixels) 0.16" 580 63 s per 5" scanned
Deep maps dwell at each slit position for a longer integration time in order to detect the weakest polarization signals possible (e.g., weak fields in quiet Sun).	Time per slit position FOV along slit Sampling along slit Polarimetric S/N Mapping Rate Full width scan time	up to 12.8 s 164" (1,024 pixels) 0.16" >103 up to 400 s per 5" scanned approx. 7 hours

* In fast-map mode, the Stokes profiles both at neighboring pairs of slit positions and at pairs of neighboring pixels along the slit are summed on board the spacecraft, hence "binned 2×2".

More details are the SOT-SP Data Products page on LMSAL.

Go to top of this page ⏏

---

References

Mission Wide

• The Hinode (Solar-B) Mission: An Overview
  Kosugi, T., Matsuzaki, K., Sakao, T., Shimizu, T., Sone, Y., Tachikawa, S., Hashimoto, T., Minesugi, K., Ohnishi, A., Yamada, T., Tsuneta, S., Hara, H., Ichimoto, K., Suematsu, Y., Shimojo, M., Watanabe, T., Davis, J.M., Hill, L.D., Owens, J.K., Title, A.M., Culhane, J.L., Harra, L., Doschek, G.A., and Golub, L.
  2007, Solar Physics, 243, pp. 3-17

SOT

• The Solar Optical Telescope for the Hinode Mission: An Overview
  Tsuneta, S., Suematsu, Y., Ichimoto, K., Shimizu, T., Otsubo, M., Nagata, S., Katsukawa, Y., Title, A., Tarbell, T., Shine, R., Rosenberg, B., Hoffmann, C., Jurcevich, B., Levay, M., Lites, B., Elmore, D., Matsushita, T., Kawaguchi, N., Mikami, I., Shimada, S., Hill, L., and Owens, J.
  2008, Solar Physics, 249, pp.167-196
• The Solar Optical Telescope of Solar-B (Hinode): The Optical Telescope Assembly
  Suematsu, Y., Tsuneta, S., Ichimoto, K., Shimizu, T., Otsubo, M., Katsukawa, Y., Nakagiri, M., Noguchi, M., Tamura, T., Kato, Y., Hara, H., Mikami, I., Saito, H., Matsushita, T., Kawaguchi, N., Nakaoji, T., Nagae, K., Shimada, S., Takeyama, N., and Yamamuro, T.
  2008, Solar Physics, 249, pp.197-220
• Polarization Calibration of the Solar Optical Telescope onboard Hinode
  Ichimoto, K., Lites, B., Elmore, D., Suematsu, Y., Tsuneta, S., Katsukawa, Y., Shimizu, T., Shine, R., Tarbell, T., Title, A., Kiyohara, J., Shinoda, K., Card, G., Lecinski, A., Streander, K., Nakagiri, M., Miyashita, M., Noguchi, M., Hoffmann, C., and Cruz, T.
  2008, Solar Physics, 249, pp.233-261
• Image Stabilization System for Hinode (Solar-B) Solar Optical Telescope
  Shimizu, T., Nagata, S., Tsuneta, S., Tarbell, T., Edwards, C., Shine, R., Hoffmann, C., Thomas, E., Sour, S., Rehse, R., Ito, O., Kashiwagi, Y., Tabata, M., Kodeki, K., Nagase, M., Matsuzaki, K., Kobayashi, K., Ichimoto, K., and Suematsu, Y.
  2008, Solar Physics, 249, pp.221-232
• The Hinode Spectro-Polarimeter
  Lites, B. W., Akin, D. L., Card, G., Cruz, T., Duncan, D. W., Edwards, C. G., Elmore, D. F., Hoffmann, C., Katsukawa, Y., Katz, N., Kubo, M., Ichimoto, K., Shimizu, T., Shine, R. A., Streander, K. V., Suematsu, Y., Tarbell, T. D., Title, A. M., and Tsuneta, S.
  2013, Solar Physics, 283, pp.579-599
• The SP_PREP Data Preparation Package for the Hinode Spectro-Polarimeter
  Lites, B. W., and Ichimoto, K.
  2013, Solar Physics, 283, pp.601-629

Go to top of this page ⏏