Instruments Operation Science Information Miscellaneous
| SOT | Solar Optical Telescope - Operations |
|---|
Information for HOP-SOT Proposers (1 July 2008)
Please follow the general guidelines for HOP submission described in the Hinode page at ISAS . This page describes information specific to SOT. Detailed information about the instrument is available from the link on the left or from the SOT Analysis Guide (SAG).
- Observing in the low telemetry situation
- Telemetry amount allocated to SOT is normally 70% of the total downlink amount, and about 1000 - 2000 Mbits per day on average. But the downlink size changes depending on the number of downlink stations, and is updated every planning period (see the HINODE daily event page). When the telemetry allocation is smaller than expected, a SOT CO may shorten the duration of an observation or reduce the time cadence in order to fit within the allocation.
- In order to conserve telemetry downlinked to the ground, JPEG lossy compression is applied for all images. The Q factor of the JPEG compression can be changed from Q50 (very lossy) to Q98 (almost lossless). When requesting high-quality images with the less lossy compression without saving data volume, please specify this in a proposal. Otherwise, our standard Q factors (75 or 65) are used.
- In order to conserve telemetry downlinked to the ground, SP data are taken in single side (of CCD) mode, acquiring one of two orthogonal polarization states unless dual side mode is requested in the proposal. The S/N in the single side mode is 1/√2 worse than that in the dual side mode. If you need higher S/N in your SP observation, please describe not only the number of integration cycles but the choice of single side or dual side in the proposal.
- Restrictions of NFI observations
- Na I D 5896A is the default line for Stokes IV (longitudinal magnetograms) and Doppler observations due to its higher light level and robust prefilter.
- H α 6563A is available only when absolutely necessary.
- Fe I 6302.5A is not available for photospheric magnetic field measurements due to shift of the blocking filter caused by long exposure to UV light early in the mission.
- Some types of Dopplergrams (DGs) and Stokes IV+Dopplergrams (IVDGs) are available in the following spectrum lines with certain wavelength offsets:
- Na I D 5896A DG ±160mA
- Na I D 5896A IVDG ±160mA
- Mg I b 5172A DG ±116mA
- Mg I b 5172A IVDG ±116mA
- Fe I 5576A DG ±140mA
- Fe I 5250A IVDG ±120mA
- Longitudinal magnetograms (Stokes IV) or Stokes images (IQUV) are available at any single wavelength offset within any line (though QU sensitivity in Na D and H α is low).
- Only one spectrum line in NFI can be used in an observing program. For example, Na I D 5896A and Mg Ib 5172A cannot be used simultaneously. This is because frequent use of the tunable filter sometimes causes appearance of blemishes (bubbles) obscuring an image over part of the field of view. There is a possibility that a NFI observation may be postponed due to bubble appearance in the tunable filter. One NFI wavelength can be used together with any wavelengths in BFI.
- Some other NFI observing programs are possible. For specific NFI questions, you may contact sot_nfi (at) lmsal.com or one of the SSCs below.
- Examples of SOT observing programs with data volume
- Note that an FG program can run simultaneously with an SP program without interference unless highest possible cadence is attempted. The combined data volume must fit within the SOT allocation, but sharing between FG and SP is completely up to the observer.
- FG
- The following tables show typical FG observations and their data volume. The JPEG compression of Q75 is used in all cases. The FOV can be matched to the desired target size in both BFI and NFI. Cadences are flexible down to about 8 seconds for images or about 20 seconds for Dopplergrams or magnetograms. Nested loops can produce context images at lower cadence in one observing program.
- BFI only
Filter FOV Summing Data Cadence Duration Data amount CN CaH G-b Blue Green Red NFI 3883 3968 4305 4504 5550 6684 x 55"x111" 2x2 (0.108"pix) 512x1024 8 sec 1 hour 520 Mbits x 55"x 55" 1x1 (0.054"pix) 1024x1024 16 sec 1 hour 270 Mbits x 221"x111" 2x2 (0.108"pix) 2048x1024 64 sec 1 hour 260 Mbits x 55"x 55" 1x1 (0.054"pix) 1024x1024 16 sec 1 hour 340 Mbits x 221"x111" 2x2 (0.108"pix) 2048x1024 64 sec 1 hour 390 Mbits x x 111"x111" 2x2 (0.108"pix) 1024x1024x2 64 sec 1 hour 330 Mbits x x x x x x 221"x111" 2x2 (0.108"pix) 2048x1024x6 320 sec 1 hour 420 Mbits
- NFI only
Filter FOV Summing Data Cadence Duration Data volume CN CaH G-b Blue Green Red NFI 3883 3968 4305 4504 5550 6684 Na I D 5896 IV -160mA 328"x164" 2x2 (0.16"pix) 2048x1024x2 64 sec 1 hour 510 Mbits Na I D 5896 IVDG ±160mA 164"x164" 2x2 (0.16"pix) 1024x1024x4 64 sec 1 hour 510 Mbits Fe I 5576 DG ±140mA 328"x164" 2x2 (0.16"pix) 2048x1024x2 64 sec 1 hour 450 Mbits
- BFI + NFI
Filter FOV Summing Data Cadence Duration Data volume CN CaH G-b Blue Green Red NFI 3883 3968 4305 4504 5550 6684 x x 221"x111" 2x2 (0.108"pix) 2048x1024x2 320 sec 1 hour 180 Mbits Na I D 5896 IV -160mA 225"x113" 2x2 (0.16"pix) 1408x704x2
- The following tables show typical FG observations and their data volume. The JPEG compression of Q75 is used in all cases. The FOV can be matched to the desired target size in both BFI and NFI. Cadences are flexible down to about 8 seconds for images or about 20 seconds for Dopplergrams or magnetograms. Nested loops can produce context images at lower cadence in one observing program.
- SP
- The following tables show typical SP observations and their data volume with one scan when the single side mode is used. When the dual side mode is used, the data volume is simply doubled. The JPEG compression of Q75 is used in all cases. Somewhat greater compression can be achieved with Q50 or Q65, with small effect on integrated Stokes maps or inversion results.
- Normal map: 0.16"pixel, 4.8sec integration (6 cycles)
FOV Data Duration Data volume 320"x164" 2000x(1024x112x1x4) 166 min 2280 Mbits 164"x164" 1024x(1024x112x1x4) 85 min 1160 Mbits 123"x123" 768x( 768x112x1x4) 64 min 660 Mbits 82"x 82" 512x( 512x112x1x4) 43 min 290 Mbits 19"x 82" 120x( 512x112x1x4) 10 min 68 Mbits 3.8"x 82" 24x( 512x112x1x4) 2 min 14 Mbits
- Fast map: 0.32"pixel, 3.2sec integration (2 cycles x2)
FOV Data Duration Data volume 320"x164" 1000x( 512x112x1x4) 60 min 600 Mbits 164"x164" 512x( 512x112x1x4) 31 min 310 Mbits 123"x123" 384x( 384x112x1x4) 23 min 170 Mbits 82"x 82" 256x( 256x112x1x4) 15 min 77 Mbits 20"x 82" 64x( 256x112x1x4) 4 min 19 Mbits 5.1"x 82" 16x( 256x112x1x4) 1 min 5 Mbits
- Deep map: 0.16"pixel, 9.6sec integration (12 cycles)
FOV Data Duration Data volume 164"x164" 1024x(1024x112x1x4) 167 min 1380 Mbits 123"x123" 768x( 768x112x1x4) 125 min 770 Mbits 82"x 82" 512x( 512x112x1x4) 84 min 340 Mbits 19"x 82" 120x( 512x112x1x4) 20 min 81 Mbits 3.8"x 82" 24x( 512x112x1x4) 4 min 16 Mbits
- The following tables show typical SP observations and their data volume with one scan when the single side mode is used. When the dual side mode is used, the data volume is simply doubled. The JPEG compression of Q75 is used in all cases. Somewhat greater compression can be achieved with Q50 or Q65, with small effect on integrated Stokes maps or inversion results.
- Contact
- Science Schedule Coordinators (SSCs)
Tom Berger (berger (at) lmsal.com)
Takashi Sekii (sekii (at) solar.mtk.nao.ac.jp)
- Science Schedule Coordinators (SSCs)
Links
- HINODE Operation Page
- SOT Timeline
- Data Analysis
- Data Quick Look
- SOT Instrument Status