Observation of the Airglow from the ISS by the IMAP Mission *Y

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2013/3/13(ANGWIN workshop, Tachikawa) Observation of the airglow from the ISS by the IMAP mission *Y. Akiya [1], A. Saito [1], T. Sakanoi [2], Y. Hozumi [1], A. Yamazaki [3], Y. Otsuka [4]

[1] Graduation School of Science, Kyoto University , [2] PPARC, Tohoku University, [3] ISAS/JAXA, [4] STE Laboratory, Nagoya University

----- Outline -----

Introduction of the IMAP mission

Visible and near-infrared spectrographic imager

Samples of airglow observation by VISI

Summary “ISS-IMAP” mission

Ionosphere, Mesosphere, Upper atmosphere and Plasmasphere Imagers of the ISS-IMAP mapping mission from the mission International Space Station (ISS)

Observational imagers were installed on the Exposure Facility of Japanese Experimental Module: August 9th, 2012.

Initial checkout: August and September, 2012

Nominal observations: October, 2012 - [Pictures: Courtesy of JAXA/NASA]

[this issue]. According to characteristics of airglow emissions, wavelength range from 630 to 762 nm. Typical total intensity of such as intensity, emission height, background continuum, etc., we airglow is 100 1000 R as listed in Table 1, and 10 % variation of selected the airglow emissions which will be measured with VISI, the total intensity must be detected in order to investigate the and determined the requirements for instrumental design. The airglow variation pattern. In addition, short exposure cycle less targets and requirements are summarized in Table 1. than several seconds is necessary to measure small-scale airglow Table 1. Scientific Targets of VISI signatures (see Table 1) considering the orbital speed of ISS (~8 km/s). Airglow Required Region Scientific Typical A sectional view of VISI and its specifications are given in (waele- spatial (height) target intensity Figure 4 and Table 2, respectively. A grism imaging spectrometer ngth) resolution that consists of fast and distortion-free objective lens (F/0.96), upper- gravity two-line-slits, collimator and CCD sensor is designed to meet the O thermosphere wave, 50 km 100 R* high sensitivity, the wide wavelength coverage, the spatial (630nm)“ISS-IMAP” and ionosphere ionospheric mission resolution requirements, and the wide field-of-view (90 degrees). (250 km) disturbances The optical system of VISI is optimized at the off-axis gravity OH mesopause field-of-view, not around the optical center axis. In normal optics, Two imagerswave, are 32set km in1000 MCE R and (730nm) (85 km) image quality is the best around the optical axis, and it is degraded temperature EUVI toward the edge of field-of-view. However, both forward and observelower- from the Exposure O2 400 field-of-views of VISI are 45 degrees off-axis separated from the thermospehre gavity wave 32 km (762nm)Facility of Japanese ExperimentR/nm optical center axis, and incident light around the optical axis is not (95km) used. Thus, we gained the sensitivity at the off-axis field-of-views 6 2 Module*R: Rayleigh (10 /4/ on photons/cm the/str/s) ISS. by using some aspherical lenses in the optics. In addition, a

distortion-fee optical system is adopted to minimize distortions. Smile distortion is estimated to be better than 5 pixels. All VISI (Visible and near-infrared surfaces of optical material are space qualified anti-reflection spectrographic imager) observes(AR) coated. Total throughputs of this optics including a bend mirror and a grims (absolute efficiency of VISI~0.63) are 0.47 at 630 airglow emission with line nm and 0.53 at 762 nm.

scanningFig. 2. (left) Kibo in Exposedthe module.nadir MCE direction. will be mounted to the port at top-right. (right) Constituents of MCE. EUVI (Extreme ultraviolet 2.1 Mission Overview Kibo EF has several ports to install imager) payloads, and MCE observes will be mounted resonance to one of them as shown in Figure 1. MCE is a complex module consisting of five instruments.scattering VISI is installed lightat the bottom from of MCE plasma to look down in to the earth. ISS is orbiting at an altitude range of 350 450 km with a theperiod ofupper ~90 min and atmosphere an inclination of 52 degrees in rangingthe from +51.6 to 51.6 degrees in geographical latitude. As shown in limb direction. Figure 3, VISI has two field-of-views pointing 45 degrees forward Fig. 3. Schematic drawing of the field-of-of vies and 45 degrees backward of the orbital direction. Due to the height [Sakanoi et al., 2011] of VISI mapped at the emission layers. difference between ground/clouds and airglow emission layers, the spatial relationship between the structure of ground and cloud reflections and airglow pattern seen in the forward field-view data Table 2. Specifications of VISI should be displaced to that seen in the backward field-view data. Rectangular-shaped (90 x 0.09 degrees) In this way, we subtract the background contaminations from Field-of-view field-of-views pointing 45 degrees forward and measured data. Each field-of-view has a wide viewing angle (90 45 degrees backward (see Figure 3) degrees) perpendicular to the orbital plane whose mapped widths Objective lens F/0.96, and f= 5.5 mm are ~600 km at an altitude of 95 km and ~300 km, respectively. Spectroscopic Wavelength coverage 630 762 nm with VISI will perform line-scanning for forward and backward properties resolution of ~1.0 nm/pixel (R~800) field-of-views, that is, continuous measurement of airglow e2V 47-20 back-illuminated AIMO, 1024 x 1024 CCD sensor emissions in nighttime. Successive exposure operation at an pixels, 1 pixel size=13.3 x 13.3 um interval of a few to several sec (described later) contributes to Below -25 deg. C with a Peltier electrical cooling CCD cooling obtain seamless scanning images for the airglow emissions in the connected to a radiator toward the earth nightside hemisphere. Size 450 (X) x 240 (Y) x 210 (Z) *

Weight and power 14.5 kg, 7.9 W

3. Instrumental Design * X, Y, Z directions are in the ISS coordinate system. VISI optics is designed to have sufficient sensitivity in order to achieve two line-scannings of faint airglow emissions in the A bend mirror is adopted to stabilize the instrument for

2 IEEJ Trans. , Vol., No., [http://eol.jsc.nasa.gov]

Airglow Aurora EUVI-FOV

VISI-FOV Extreme Ultraviolet Imager (EUVI)

Resonant scattering: 83.4 nm (O+), 30.4 nm (He+)

Observation in the day side and the night side

Limb observation in backward FOV 15 deg.

Weight: 19.3 kg, Size: 170 mm X 370 mm X 480 mm

Initial test of EUVI: Lid close on August 11, 2012

EUVI He+ (September 26, 2012 07:26UT) Visible and near-infrared spectrographic imager (VISI)

Airglow: O (630 nm), OH (8-3 band around 730 nm), O2 (762 nm)

Observation in the night side

Nadir direction observation with FOVs pointing 45 degrees forward and 45 degrees backward

Weight: 14.5 kg, Size: 170 mm X 370 mm X 480 mm

Several observational mode

CCD

ISS moving direction

Backward FOV Forward FOV Observational mode of VISI

Calibration mode Calibration mode

Images are read out without binning. Full frame data are recorded.

Exposure time: 2 - 4 seconds

Spectral mode

Data at three ROIs (ROI = Region of interest) determined in the forward FOV and three ROIs in the backward FOV are recorded.

Exposure time: 1 - 6 seconds

Binning: 8, 16, 32 pixels in spatial direction

Peak mode

The peak and background on each spectrum in the ROIs are determined and recorded. Left: Spectral mode Exposure time and binning are same as Right: Peak mode spectral mode. Averaged intensity of calibration data spectrum Averaged for 56 calibration mode data 400 taken from August to Forward FOV [6] December, 2012. Backward FOV 300 [1] 557.7nm(O)

[2] 589.6nm(Na) [9] [3] 630.0nm(O) 200 [1] [4] 636.4nm(O) [2]

Intensity [R/nm] Intensity [3] [5] [7] [5] 732.0nm(O+) 100 [4] [8]

[6] 761.9nm(O2) 0 [7] 777.4nm(O) 500 600 700 800 900 [8] 844.6nm(O) Wavelength [nm]

[9] 864.5nm (O2) Averaged intensity of OH band emissions Average of 56 calibration mode data taken from 70 Forward FOV August to December, [6] Backward FOV 2012. 60 [2][3] [5] [1] 7-1 (560-570nm) [1] [4] 50 [2] 8-2 (590-600nm) [7] 40 [8] [3] 5-0, 9-3 (620-640nm) 30 [4] 6-1 (650-670nm) Intensity [R/nm] Intensity 20 [5] 7-2 (690-705nm) 10 [6] 8-3, 4-0, 9-4, 5-1 (720-810 nm) 0 500 600 700 800 900 [7] 6-2 (840-860nm) Wavelength [nm] [8] 7-3 (880-900nm) 762-nm Peak mode observation Observation around 2012/9/25 02:15 UT

762-nm (95 km altitude) Background 630-nm Peak mode observation Observation around 2012/9/25 02:15 UT

630-nm (250 km altitude) Background Calibration and ﬂattening of observational data

White pixels are already 1000 subtracted from the observational data.

Two strong lines are seen in the 800 762-nm forward FOV peak image. These are also seen in background images. Counts 600 The strength of this effect is not uniform in the same observation. Strength is Coordinate [pixel] affected by the intensity of the 400 light passed the optical system. 0 10 20 30 40 50 60 Summary ISS-IMAP mission started the observation of the upper atmosphere in August. Nominal observations by VISI and EUVI has been carried out.

VISI observes the airglow in the nadir direction with two ﬁeld of views. Target is the airglow originated from the atomic oxygen (630-nm wavelength), OH molecules (0-0 band) and oxygen molecules (762- nm wavelength). It is able to observe 557.7-nm emission from the atomic oxygen, Na emission and other OH band emissions in calibration mode observation.

It is needed to subtract noise caused by electric interference and non- uniformity of optical slit. Noise caused from electrical part has same phase and appearance. On the other hand, noise caused from optical part is different in every observation. Calibration of observational data is needed.

Sensitivity between two ﬁeld-of-views of VISI are slightly different. This is also thought to be caused from the non-uniformity of the slit width.

894 K. SHIOKAWA et al.: OPTICAL MESOSPHERE THERMOSPHERE IMAGERS

Ground-based airglow observations

ALOHA-93 campaign

FRONT campaign

OMTI: Optical Mesosphere Fig. 8. All-sky airglow images at OI (557.7 nm, 96 km), O2 Atmospheric (0-1) bands ( 94 km), Na (589.3 nm, 90 km), and OH bands ( 87 km) observed at Shigaraki for 00:01–00:31 LT on March∼ 4, 1998. The OH image is taken every∼ 30 s, while the images of∼ other emissions are taken∼ every 2 Thermosphere Imagers min. These images at four emission lines are taken at exactly a same time using four all-sky cameras. Upward is toward the north and leftside is toward the east. The images are deviations from the average image for 00:01–0031 LT.

Another ground-based Three kinds of wave structure are seen in these images. but is not clear in the Na and OH images. A schematic diagram of the wave structures seen in the The second one is the large-scale EW structure which OI image at 0021 LT is shown in Fig. 9. The ﬁrst one is moves northward with a velocity of 80 m/s in the OI images. airglow imager will be putthe large-scale “band” structure in the NNW-SSE direction This structure, which is more or less∼ like a boundary between which moves toward the ENE. The velocity of the motion is intense and weak emissions, is seen at the bottom edge of the at Hawaii as a part of 160 m/s in the OI images assuming an emission altitude of OI and O2 images at 0001 LT and around the center of the Fig. 8. All-sky airglow images at OI (557.7 nm, 96 km), O Atmospheric∼ (0-1) bands ( 94 km), Na (589.3 nm, 90 km), and OH bands ( 87 km) ∼ 2 96Observations km. The horizontal∼ wavelengthof OH of∼airglow this structure by is OMTI100∼ images at 0031 LT. This structure is relatively weak in the observed at Shigaraki for 00:01–00:31 LT on March 4, 1998. The OH imagekm. isThis taken structure every 30 s, is while clearly the images seen in of otherthe OI emissions and O areimages taken∼ everyNa 2 and OH images, but can be seen in the 0031 LT images. ISS-IMAPmin. These images project. at four emission lines are taken at exactly a same time[Shiokawa using four all-sky cameras. et al., Upward 1999] is toward the north and leftside2 is toward the east. The images are deviations from the average image for 00:01–0031 LT.

Three kinds of wave structure are seen in these images. but is not clear in the Na and OH images. A schematic diagram of the wave structures seen in the The second one is the large-scale EW structure which OI image at 0021 LT is shown in Fig. 9. The ﬁrst one is moves northward with a velocity of 80 m/s in the OI images. the large-scale “band” structure in the NNW-SSE direction This structure, which is more or less∼ like a boundary between which moves toward the ENE. The velocity of the motion is intense and weak emissions, is seen at the bottom edge of the 160 m/s in the OI images assuming an emission altitude of OI and O2 images at 0001 LT and around the center of the 96∼ km. The horizontal wavelength of this structure is 100 images at 0031 LT. This structure is relatively weak in the ∼ km. This structure is clearly seen in the OI and O2 images Na and OH images, but can be seen in the 0031 LT images. BROADFOOT 0 0 IAI 0 •t/S CO 0 0 NV/S C.O 0 0 -•- H AND 013-1AV•t c',,l 0 BELLAIRE: - - _ _•o - _ _o - - _ -? - _ _•o - -? - -,• - _ _•o - _ - - - _ _•o - _ _•o - _ - _ -- c• o o oo ¸ • r 0 oo • 0 •) ø ¸ ø ¸ 0 0 0 • o Airglow observation from space shuttle o o•' OBSERVATIONS • I FE OF EE THE I Lr3 0 NIGHT I IAI El- 0 •tñS 0 0 I o It-) o o 0 NV/S Lr3 0 AIRGLOW I o 0 0 H I 013--IAV•t -- 17,131 Observed by GLO-1 during the STS 53 shuttle mission [Broadfoot et al., 1999]

Many observations of the airglow are made by the ground-based imager, rockets and satellites.

Airglow is observed with spectrographic image in the nadir direction in the ISS-IMAP mission. Airglow observations by rockets and satellites D02S05 HECHT ET AL.: TOMEX PHOTOMETER RESULTS D02S05

Example of rocket observations (Photometer of TOMEX project) are shown in the right ﬁgures

TIMED satellite

WINDII, HRDI on UARS satellite

ISUAL/FORMOSAT-2

Multi-spectral auroral camera on INDEX (Reimei) Figure 6. (top) The measured O2A VER (solid line) versus altitude compared to the four TIME-GCM predictions (see Figure 3). (middle) Same but for greenline.[Hecht (bottom) et Same al., but for OHM2004] (9, 4). On each satellite plot a vertical solid line is shown offset from a vertical dashed line taken as a zero reference line. This solid line represents the one sigma error as function of altitude in the derived VERS based on the uncertainties in the measured counting rates in Figure 5.

data and shown in Figure 7a. The agreement is quite good density is taken from TIME-GCM. Here the solid line above 85 km except for the dip at 93 km. shows [O] data from O2A, the dashed line shows the [O] [26]Figure9showsacomparisonbetweenthederived data from OHM using the Turnbull and Lowe model, the [O] profile from the O2A data and the four TIME-GCM solid line are the [O] data from OHM using the Yee model, model predictions. Clearly the peak is lower in altitude and and the heavy solid line shows the [O] data from OHM magnitude than the model predicts. One model run, the using the Yee model with the [H] data multiplied by 2. preferred has a peak at about the right altitude but the shape [28] The agreement here is good, except for when the Mies of the data above 85 km is different. model is used, suggesting that the airglow derived [O] data are consistent. Because of the uncertainty in the magnitude of the 3.5. Atomic Oxygen Density Profiles From OHM [H] profile an exact value for the transition probabilities and O2A cannot be established. However, taking the TIME-GCM [27]Intheregionbetween82and90kmwhere [H] as accurate and taking f(9) to be 0.32 then the value for equations (1b) and (1c) apply, the [O] obtained from O2A A(9, 4)/A(9) is close to that given by Yee. It should be is compared with that obtained from OHM as shown in emphasized that while in this case the Mies values appear to Figure 10. The top panel of Figure 10 shows the O2A result be inconsistent this does not mean that the other Mies (thin solid line) compared to the OHM result using transition probabilities are incorrect. Rather, it indicates that equation (1b) and either the Yee model (heavy solid line), a new evaluation of the transition probabilities is needed. the Turnbull and Lowe model (dashed line) or the Mies model (dotted line). While the qualitative shapes of all three agree, the magnitudes are best given either by the Yee or 4. Discussion Turnbull and Lowe models. The bottom panel of Figure 10 [29]ClearlythemeasuredO2Aandgreenlineemissions uses the more exact equation (1c) where here the hydrogen and the derived [O] profile are inconsistent with the model

9of16 Airglow observation from space shuttle BROADFOOT 0 0 IAI 0 •t/S CO 0 0 NV/S C.O 0 0 -•- H AND 013-1AV•t c',,l 0 BELLAIRE: - - _ _•o - _ _o - - _ -? - _ _•o - -? - -,• - _ _•o - _ - - - _ _•o - _ _•o - _ - _ -- c• o o oo ¸ • r 0 oo • 0 •) ø ¸ ø ¸ 0 0 0 • o o o•' OBSERVATIONS • I FE OF EE THE I Lr3 0 NIGHT I IAI El- 0 •tñS 0 0 I o It-) o o 0 NV/S Lr3 0 AIRGLOW I o 0 0 H I 013--IAV•t -- 17,131 Observed by GLO-1 during the STS 53 shuttle mission [Broadfoot et al., 1999] View of ISS-IMAP instruments in “MCE”

MCE = Multi-mission consolidated equipment

1.8 m x 1.0 m x 0.8 m, EUVI(IMAP) 450 kg weight

Five missions (IMAP, GLIMS, SIMPLE, SIMPLE REXJ and HDTV) uses a single port this time.

REXJ GLIMS

VISI(IMAP)

HDTV Speciﬁcation of VISI

Size 450 mm x 240 mm x 210 mm

Weight 14.5 kg

e2V 47-20 back-illuminated CCD AIMO, 1024 x 1024 pixels sensor 1 pixel size = 13.3μm x 13.3μm

Rectangular shaped Field-of- (90 x 0.09 deg) view FOVs pointing 45 degrees

CCD (FOV) forward and 45 degrees backward Objective F/0.96, f = 5.5 mm lens ISS moving direction

Spectrosc Wavelength coverage: 600 - Backward FOV Forward FOV opic 800 nm in the both FOVs properties Resolutions ~ 1.0nm / pixel Speciﬁcation data:[Sakanoi et al., 2011] Observational target of VISI Atomic oxygen (O) airglow

630-nm wavelength

~ 250 km altitude (F2 layer), ~ 100 kR

OH molecule airglow

observes in 730-nm wavelength

~ 87 km altitude, ~ 1kR

Oxygen molecule (O2) airglow

762-nm wavelength

~ 100 km altitude 630-nm emission from atomic oxygen

1 3 O( D) → O( P2) + hν(630.0nm)

1 3 O( D) → O( P1) + hν(636.4nm)

1 3 O( D) → O( P0) + hν(639.2nm)

Intensity of 630.0-nm wavelength emission at night is ~100 kR

The lifetime of the excited state (1D) of the atomic oxygen is ~134 seconds. These atoms radiates at the altitude of ~250 km (~F2 layer). 762-nm emission from oxygen molecule

1 + The emission from oxygen molecule O2(b Σ g) 3 - → O2(X Σ g) has two intense bands:

761.9-nm, (0-0) band

864.5-nm, (0-1) band

Radiative lifetime of metastable molecules is ~12 seconds. These molecules emit at the altitude in 90 - 100 km. These emissions are usually absorbed by the Earth atmosphere and difﬁcult to observe from the ground. Hydroxyl emissions

Hydroxyl emission arises in the upper atmosphere at ~87 km altitude. Average intensity of this emission is ~ 1 kR.

(8-3) band is around 730-nm wavelength

OH molecules are thought to be produced by the reactions

in below. (M = O2 or N2)

The ozone-hydrogen reaction:

O + O2 + M → O3 + M

H + O3 → OH + O2

The reaction of perhydroxyl with atomic oxygen:

H + O2 + M → HO2 + M

O + HO2 → OH + O2 Data processing

VISI raw data Camera format data Take out observational data tfb data One file for one raw data file Separate data into groups for each observations decoded data One file for one snap shot Refer the ROM table (Observational mode, Exposure time), sensitivity Make continuous data file for one observation Level-1 data One file for one observation (one mode) IDL routines q - parameters, transfer to absolute plotted data intensity, FOV angle JPEG, FITS, IDL save altitude, attitude Level-2 data “Science” data Example data of Calibration mode

# Version: 1.0 ←Version of data # Program: visi_level1_make.pro (Ver. 1.0) ←IDL procedure used # Creator: T. Sakanoi ←Data creator # Create Date: Mon Oct 1 14:43:55 2012 ←Created date # Data File Start: IMP_EXP_2012-09-05.log_tfb_VISI3706_12090509452305_TBL14_0543207_decode.dat ←First decoded data # Data File End : IMP_EXP_2012-09-05.log_tfb_VISI3706_12090509452305_TBL14_0543207_decode.dat ←Last decoded data # Data File Number: 1 ←Number of shots in the observation # VISI Table Version: 2012-02-21 ←Date of ROM table updated # Mode: ←Observational mode (No description for CAL mode) # Binning Number (a) (pix): 32 ←Binning # Exposure Time (b) (sec)= 6.00000 ←Exposure time # Exposure Cycle (sec)= 6.58800 ←Exposure time + read out # X-pix, Y-Pix, ROI number= 1028 1072 1 ←Number of pixels in Spatial, Wavelength and number of ROI # Unit: Counts in a exposure time ←Physical unit of the data in below # Sensitivity at 630,730,762nm (c) (el/R/pix/sec): 0.0320000 0.0320000 0.0300000 ←Sensitivity # Gain : 0 ←Mode of gain # Conversion Factor from Count to Electron (e) : 1.24000 ←Relation between counts and electrons # NOTICE: You get intensity in Rayleigh by Count*(e)/(a)/(b)/(c) # END OF HEADER

File number= 0/ 0 ←Number of ﬁle is 1 if 0/0 Date, UT(hhmmss)= 20120905 094523 ←Time of observational shot O 630nm, Backward,ROI= 5/ 6 (←This description can be ignored in CAL mode) 691 691 690 689 692 689 688 688 688 686 ←Data are written in below 688 691 689 691 684 686 688 686 690 693 Example data of Spectral mode

# Version: 1.0 # Program: visi_level1_make.pro (Ver. 1.0) # Creator: T. Sakanoi # Create Date: Mon Oct 1 14:43:44 2012 # Data File Start: IMP_EXP_2012-09-05.log_tfb_VISI0001_12090500212205_TBL01_0003986_decode.dat # Data File End : IMP_EXP_2012-09-05.log_tfb_VISI0001_12090500212205_TBL01_0003986_decode.dat # Data File Number: 1 # VISI Table Version: 2012-02-21 # Mode: Spectral mode # Binning Number (a) (pix): 16 # Exposure Time (b) (sec)= 1.00000 # Exposure Cycle (sec)= 1.86200 # X-pix, Y-Pix, ROI number= 64 12 6 # Unit: Counts in a exposure time # Sensitivity at 630,730,762nm (c) (el/R/pix/sec): 0.0320000 0.0320000 0.0300000 # Gain : 0 # Conversion Factor from Count to Electron (e) : 1.24000 # NOTICE: You get intensity in Rayleigh by Count*(e)/(a)/(b)/(c) # END OF HEADER

File number= 0/ 0 ←Number of ﬁle is 1 if 0/0 Date, UT(hhmmss)= 20120905 002122 ←Time of observational shot O2 762nm, Forward, ROI= 0/ 6 ←Source of emission, wavelength, observed FOV, ROI number 521 521 522 530 585 536 3488 556 551 543 539 564 613 532 539 535 544 531 533 535 536 538 699 548 542 550 557 567 567 571 ←Data are written in below 561 561 551 561 561 551 558 558 575 579 583 575 564 558 544 554 539 583 542 540 535 533 535 527 525 533 531 528 525 519 517 521 519 491 Example data of Peak mode # Version: 1.0 # Program: visi_level1_make.pro (Ver. 1.0) # Creator: T. Sakanoi # Create Date: Mon Oct 1 14:43:45 2012 # Data File Start: IMP_EXP_2012-09-05.log_tfb_VISI0002_12090500212505_TBL07_0000981_decode.dat # Data File End : IMP_EXP_2012-09-05.log_tfb_VISI0662_12090500422405_TBL07_0000912_decode.dat # Data File Number: 661 # VISI Table Version: 2012-02-21 # Mode: Peak mode # Binning Number (a) (pix): 16 # Exposure Time (b) (sec)= 1.00000 # Exposure Cycle (sec)= 1.86200 # X-pix, Y-Pix, ROI number= 64 2 6 # Unit: Counts in a exposure time # Sensitivity at 630,730,762nm (c) (el/R/pix/sec): 0.0320000 0.0320000 0.0300000 # Gain : 0 # Conversion Factor from Count to Electron (e) : 1.24000 # NOTICE: You get intensity in Rayleigh by Count*(e)/(a)/(b)/(c) # END OF HEADER

File number= 0/ 660 ←1st data of 660 data in this observation Date, UT(hhmmss)= 20120905 002125 ←Time of observational shot O2 762nm, Forward, ROI= 0/ 6 ←Source of emission, wavelength, observed FOV, ROI number 548 551 550 557 628 613 858 840 820 826 870 924 910 922 919 871 861 850 881 881 861 875 843 843 844 866 1191 860 850 846 848 872 876 893 891 850 841 871 926 936 902 907 935 964 980 979 955 925 908 935 ←Peak data 959 976 953 928 2489 890 892 791 554 548 546 548 540 532 519 524 523 520 565 545 666 578 549 545 537 539 538 535 528 534 531 530 535 532 537 540 540 530 527 535 529 537 531 534 ←Background data 531 527 533 531 535 529 530 531 537 532 532 536 537 539 534 537 538 534 543 542 533 539 528 533 528 526 537 528 520 520 523 520 515 499 Calibration mode image

2012/8/13 03:25:08 UT

Exposure time: 6 seconds Spatial direction

Line dispersion: 0.90 nm/pixel in forward FOV, 1.02 nm/pixel in backward FOV

Region for ~600 km is taken in spatial direction

Forward FOV Backward FOV Wavelength Wavelength Count values on CCD

570

560

550 Counts

540 Counts shown in the right Forward Backward ﬁgure are averaged for 60 FOV FOV pixels in each regions. 530 650 750 850 550 650 750 Wavy structure caused from Wavelength [nm] mechanical part of imager is seen in the backward FOV. Wavy noise structure

Wavy structure was not 20 found in the forward FOV. “Zero” is set for the value in the forward FOV. 10 The amplitude of the noise is estimated to be 20 counts. Period in the 0 wavelength direction is Counts estimated to be 70 pixels. -10 Amplitude of the noise Forward Backward decreases exponentially. FOV FOV This structure always -20 650 750 850 550 650 750 appears same place with Wavelength [nm] same pattern. Wavelength and intensity

Noise on this data is 400 subtracted. Counts Forward FOV O2 (0-0) Backward FOV observed has transferred to the Rayleigh units. OH Meinel band 300 (8-3)(4-0)(9-4)(5-1) Emission stronger than 10 R are observed for 630- nm, 730-nm and 762-nm 200 wavelengths. O (630nm) O (636nm) Emissions between 600 [R/nm] Intensity nm and 800 nm in 100 wavelength are able to observe in the both FOVs. 0 There are difference in observed intensity 500 600 700 800 900 Wavelength [nm] between both FOVs. Peak mode images

2013/2/3 07:11:45UT -

Exposure cycle: 1.862 seconds

Binning: 16

Image taken in 762-nm wavelength in the forward FOV are shown. Peak values are on the left and the background is on the right. Time passes from the lower part to the upper part in ﬁgures.

Vertical bright lines in ﬁgures are thought to be caused from non-uniformity of the optical system. Causes estimated

Positions of noise appear seems to be always same. This indicates noises are not caused by the optical system inside the imager.

This noise does not appear when no light comes in. This means CCD does not make noise. If the Idealistically intensity of light changes, the depression (or shape of the darkness) changes. This depression varies with the slit intensity.

The noise concerned is the non-uniformity (in μm order) in spatial direction. If the shape of slit which Shape of the is rectangular idealistically changes, the intensity of slit is not light reach to the CCD may be changed. This may uniform in μm scale be one of the cause of the “vertical” noise in peak mode ﬁgures. Back to the ground test data

4000

3000

2000 Counts

1000

0 0 200 400 600 800 1000 Coordinates

There are large noises which takes small value than other area.

Lines in the horizontal direction is the wavy structure which can be subtracted.

Blue: 630nm, Green: 730nm, Red: 762nm