HOP list   Monthly Events

HINODE Operation Plan (HOP)

accepted on

16-feb-12

 HOP No.

  HOP title

HOP 0209
Observations of Transit of Venus (ToV) 2012 June 5-6

plan term

2012/06/05-2012/06/06

 　 　

proposer

  name : Hinode operation team;
P-Team (Pasachoff, Reardon, Schneider, Golub,  Sterling);
Y-Team (Yamazaki, Kanao)		 　  e-mail : shimizu.toshifumi[at]isas.jaxa.jp
alphonse.sterling[at]nasa.gov

contact person in HINODE team

  name : Shimizu, Sterling 　  e-mail : shimizu.toshifumi[at]isas.jaxa.jp
alphonse.sterling[at]nasa.gov

 abstract of observational proposal
This HOP defines the overall plan of Hinode observations of the Transit of Venus. This plan is defined from the merger of two independent proposals from two teams, the P-Team and Y-Team, and also Hinode-team considerations.

------------------------
Venus will transit the Sun on 2012 June 5-6, for the last time until December 2117. We would like to use Hinode to observe the event with SOT, XRT, and EIS.  The ToV will be during the Hinode "eclipse" season, and so periods of night will occur during the transit as observed from Hinode.  

Our observational objectives are multi-fold:

(a) We will study the black drop effect in white-light with SOT during contacts I and IV.   A convincing explanation for this long-observed effect has been presented only recently  (e.g., Schneider et al. 2004) from TRACE observations of a Mercury transit, and that  explanation has been tested only once since that time, with TRACE observations of a Venus  transit (Pasachoff et al. 2011).  We will seek to further verify the explanation with SOT,  which has white-light resolution far superior to TRACE.

(b) We will similarly use SOT to observe the circum-Venusian "aureole," whereby light from the photosphere is refracted by the off-disk portion of the Venusian atmosphere (e.g., Pasachoff et al. 2011; Tanga et al. 2011); these aureole observations will be made between contacts I and II, between contacts III and IV, also with attempts to do so just before (after) contact I (IV).  For imaging the aureole, we will include SOT's CN filter, since interesting absorption has been observed at such wavelengths (e.g., Krasnopolsky 2006, Fig. 2), and also with other SOT/BFI filters for comparison.  Aureole observations will also allow us to determine the atmospheric scale height and its atmospheric distribution with the asymmetric distribution of the luminosity.

(c) While on-disk  we will take images in NFI and BFI filters.  We will attempt polarization  measurements, using the  continuum near 6302 with SOT/SP or at a continuum wavelength with  the NFI when Venus is on the disk.  We will also attempt resonance scattering observations.

(d) We request observations from XRT to observe Venus silhouetted against the coronal background  before, during, and after the transit.  Although flux levels are largely uncertain, it may be  possible to observe an X-ray scattered-light aureole during the entire passage. Chandra found  a peak flux of 0.5-0.6 keV from Oxygen  fluorescence lines (Dennerl et al. 2002; Bhardwaj et al.  2007, pp 21-22), which would be well suited to the Al-poly,  Al-mesh, or Ti-poly filters.  The C-poly filter could perhaps also be  used to differentiate the contribution of C and O  fluorescence lines.

(e) Well prior to first contact, XRT should attempt to image the aureole against a relatively smooth coronal background for target (d).

(f) We request slot images and slit images by EIS, including several EUV lines, in an attempt  to observe possible EUV spectral properties of the Venusian atmosphere. When the solar wind ions  impact on the ionospheric particles, the charge exchange may produce the excited emissions, such as OIV-OVII. The solar wind particles induced into the ionosphere is asymmetric in the north-south  direction, which might be observable. It would be suitable to acquire slit images as much as possible, including much before contact I and after contact IV to observe emissions against a relatively smooth, less-ionized-Oxygen emission background far above the off limb.  

(g) We request SOT, XRT, and EIS to acquire time series of SOT, XRT, and EIS images (any wavelength and filter OK) at a fixed pointing during the disk passage for roll-angle calibration (co-alignment  purpose).

(h) SOT, XRT, and EIS images for public outreach and media releases.

References:
Bhardwaj, A. 2007, Planetary & Sp. Sci. 55, 1135
Gunell et al. 2006
Dennerl, K., et al. 2002, A&A, 386, 319
Krasnopolsky, V. A. 2006, Planetary and Space Sci., 54, 1352
Pasachoff, J. M., Schneider, G. & Widemann, T. 2011, Astron. J. 2011, 141, 112
Schneider, G., Pasachoff, J. M., & Golub, L. 2004, Icarus, 168, 249
Tanga, P., et al. 2011, Icarus, in press.

 request to SOT
FOV: 218'' x 109'', 2x2 binned pixels.

Filters and Programs:

* Target (a), (b) and (h)

- From prior to contact I until contact II, and from contact III continuing after contact IV: A cycle of BFI filters, including 3883.5 CN, 4504.5 blue continuum,  5550 green continuum, and 6684 red continuum.  Cadence for most of the period could be about one image per 10 s.  For the time around the black-drop time (e.g, for about 2 min on either side of contacts I and IV), the cadence should be increased to as fast as possible (perhaps 1 image per 5 sec).  An average "best" focus  position could be used for all wavelengths.

- At about the middle of the first and second contact, and then again during the middle between contacts III and IV, there should be about 1 minute of very high cadence observations (~1 image/five sec) in a single filter.  One of these two times should use the CN filter, and another time should use one of the color filters.   The objective is to characterize the time variability of the aureole.

* Target (c), (g) and (h)

- Between contacts II and III.  A sequence of BFI and NFI images, run as a set of images, several times during the period.  Cadence is not critical, but should be run as regularly as possible  within the telemetry constraints. At least some runs should include:

  o For polarization observations: imaging in the continuum near 6302 with SOT/SP or at a continuum wavelength with the NFI.

  o If possible, a sequence of polarimetric scans through the Na D1 5896 line with the NFI, to look for resonance scattering.

 request to XRT
* Target (d), (g), and (h)

From just prior to contact I until just after contact IV:  A sequence of coronal observations with Venus in the FOV, to image the planet silhouetted against the background corona, and to look for the X-ray scattered-light Venusian aureole. Imaging either in Al-poly,  Ti-poly, or in C-poly are recommended.

From prior to contact I, it is expected that Venus could be in the XRT FOV for 1.5-2 hours prior to contact I.  XRT can try as-deep-as-feasible exposures to measure Venus against the relatively smooth coronal background.  A subfield with 2x2 binning could be used, images either in Al-poly, Al-mesh (with binning), Ti-poly, or C-poly.

In both cases, exposure times will be limited if active regions are present on the Sun, but taking a large number of images is desired so that they can possibly be combined in post-processing.  A subfield can be taken, and binning of 2x2 or even 4x4 could be used to help increase the number of images taken.

[Updated by K. Reeves:  Since Hinode is in eclipse season, XRT is restricting the use of Filter Wheel 1; this limits the filters that XRT can use to Ti-poly and Al-mesh.]

 request to EIS
* Target (f), (g) and (h)

- Before contact I as well as after contact IV, repeated slit measurements  with a couple of context slot measurements are requested. Weak Oxygen emissions may  be identified only when data are taken against a relatively smooth, less ionized  Oxygen emission background above the off limb. The slit is at a fixed position,  and Venus transits across the fixed slit.  Slit measurements are needed to isolate  Oxygen lines from nearby stronger coronal lines.

- Repeated scans in prominent EUV lines (selected by EIS team), repeated several times during disk passage.  Fluxes from the Venusian aureole may not be high, and so these will be exploratory observations. Slot (40") are more suitable.

- We request that the EIS studies for the Venus transit include the spectral lines:
  OV: 193
  OVI: 184
  (OIV: 280)

- Based on previous studies the predicted EUV emission intensities are extremely low, but observations in these exact circumstances have never been attempted before and so the actual intensities are unknown.  Therefore we request that the exposure times be as long as possible and that the observations be carried out as long as telemetry permits.  Observations when Venus is still located far above the limb may be useful for isolating the Venus-directed photons from OV/VI emissions from the solar disk.

 other participating instruments
Haleakala, Sac Peak DST, SOLIS, NST at BBSO, Hida, and many ground basedobservatories.   Also Hubble (observing lunar albedo changes).

 remarks
- The ToV event schedule (UT): views from Hinode (with orbital elms as of 2012/3/24) :

        UTC        P       V        AD    SD_Sun  SD_Ven   AZI    ZD
   2012 June 5-6
       h  m  s     deg     deg       "       "       "      deg   deg

1st  22 15 46.9   39.58  193.89   974.60  945.70   28.90  103.7 121.2
2nd  22 29 53.4   36.50  249.09   916.80  945.70   28.90  275.8 113.2
min   1  2 43.4  358.19   48.32   548.99  945.72   28.90   73.0  74.5
max   2  0 54.7  330.82  229.89   583.64  945.70   28.90  293.4  88.7
min   2 16 42.3  324.54  277.53   582.46  945.72   28.90  275.0  63.0
3rd   4 37 20.7  292.74   39.22   916.77  945.67   28.90   71.5 106.7
4th   4 49 59.5  291.30   86.46   974.56  945.66   28.90  104.3 121.0


- The relative speed on the Sun disk is about 240 arcsec/hour (~ 0.067 arcsec/sec).

- During the transit time, the diameter of the Sun is 1891.4 arcseconds and that of
 Venus  is 57.8 arcseconds.

- The data recorder (DR) should be empty prior to the onset of the transit observations, so that the maximum amount of transit data can be obtained. Also, quick release for the media becomes possible. Therefore uploads  for the period(s) prior to the transit should be managed with this in mind.

- Prior to contact I and after contact IV, SOT's FOV should be positioned at the contact  latitudes, and as far off the limb as allowed by the SOT/CT (typically FOV centered 15''  inside the limb).  This will allow attempts for observations of the Venusian aureole outside of the solar disk.


- Note: Hinode Night period (as of March 21)
XTW_EXIT   : 2012/06/05.20:53:00 ;
XTW_ENTRY  : 2012/06/05.22:01:30 ;
NGT_ENTRY  : 2012/06/05.22:07:00 ;
NGT_EXIT   : 2012/06/05.22:26:00 ;
XTW_EXIT   : 2012/06/05.22:31:30 ;
XTW_ENTRY  : 2012/06/05.23:40:00 ;
NGT_ENTRY  : 2012/06/05.23:45:00 ;
NGT_EXIT   : 2012/06/06.00:04:30 ;
XTW_EXIT   : 2012/06/06.00:10:00 ;
XTW_ENTRY  : 2012/06/06.01:18:30 ;
NGT_ENTRY  : 2012/06/06.01:23:30 ;
NGT_EXIT   : 2012/06/06.01:43:00 ;
XTW_EXIT   : 2012/06/06.01:48:30 ;
XTW_ENTRY  : 2012/06/06.02:57:00 ;
NGT_ENTRY  : 2012/06/06.03:02:00 ;
NGT_EXIT   : 2012/06/06.03:21:30 ;
XTW_EXIT   : 2012/06/06.03:27:00 ;
XTW_ENTRY  : 2012/06/06.04:35:30 ;
NGT_ENTRY  : 2012/06/06.04:40:30 ;
NGT_EXIT   : 2012/06/06.05:00:00 ;
XTW_EXIT   : 2012/06/06.05:05:30 ;








- Note: Hinode Night period (as of May 26)
Delta from March 21 times.

XTW_EXIT   : 2012/06/05.20:52:30 ; -00:30
XTW_ENTRY  : 2012/06/05.22:01:00 ; -00:30
NGT_ENTRY  : 2012/06/05.22:06:00 ; -01:00
NGT_EXIT   : 2012/06/05.22:25:30 ; -00:30
XTW_EXIT   : 2012/06/05.22:31:00 ; -00:30
XTW_ENTRY  : 2012/06/05.23:39:30 ; -00:30
NGT_ENTRY  : 2012/06/05.23:44:30 ; -00:30
NGT_EXIT   : 2012/06/06.00:04:00 ; -00:30
XTW_EXIT   : 2012/06/06.00:09:30 ; -00:30
XTW_ENTRY  : 2012/06/06.01:18:00 ; -00:30
NGT_ENTRY  : 2012/06/06.01:23:00 ; -00:30
NGT_EXIT   : 2012/06/06.01:42:30 ; -00:30
XTW_EXIT   : 2012/06/06.01:48:00 ; -00:30
XTW_ENTRY  : 2012/06/06.02:56:30 ; -00:30
NGT_ENTRY  : 2012/06/06.03:01:30 ; -00:30
NGT_EXIT   : 2012/06/06.03:21:00 ; -00:30
XTW_EXIT   : 2012/06/06.03:26:00 ; -01:00
XTW_ENTRY  : 2012/06/06.04:35:00 ; -00:30
NGT_ENTRY  : 2012/06/06.04:40:00 ; -00:30
NGT_EXIT   : 2012/06/06.04:59:30 ; -00:30
XTW_EXIT   : 2012/06/06.05:04:30 ; -01:00
XTW_ENTRY  : 2012/06/06.06:13:30 ;
NGT_ENTRY  : 2012/06/06.06:18:30 ;

[Timeline below reflects the new, May 26, times.]
[Contact times in timeline below based on Soma-san predictions No. 347, 30-May-2012]




------------------------------------------------------------------

Detailed Timeline:


Program definitions:  The timeline below repeats a few basic programs.  Here we define those programs, and below we include them in the overall timeline.
----------------

SOT Program 1:  This is run beginning between Contacts 1 and 2 when Hinode emerges from s/c night, and continuing for ~15 min after Contact 2.  Focus is variable and not optimal for several minutes following emergence from s/c night:

 BFI filter cycle w/ focusing. 2k x 2k 2x2 summing, Q 85 compression: aureole study.
     Ca H 396.8 nm  (publicity image)
     CN 388.5 nm
     Blue continuum 450.5 nm
     (focus change(?))
     Green continuum 550.5 nm
     Red continuum 668.4 nm

Cadence:  estimated 6-8 seconds between images.


SOT Program 2:  Sequence of BFI and NFI images, and an SP study.  To be run when Venus is on-disk.
This consists of three sub-programs:

o Program 2a: A cycle of six BFI filters: CN, Ca, CH, blue continuum,  green continuum, red continuum.  FOV=218''x109'', 2x2 binning.  If run once every 320 sec, this set of 6 images requires --> ~420 Mbits for 1 hour run.  In the timeline we can run it once every 180 sec; over the 246 min in the timeline alloted to Program 2a, this then uses an estimated total of ~3.1Gbits.

o Program 2b: A scan of the NFI Na I D line, including continuum near
the line.  Based on a similar scan of 2010.12.04 14:14 UT, propose:
step= 80mA, offset -504 to 456 mA, # steps = 13.  Use
FOV=218''x109'', 2x2 binning.   These 13 images --> ~ 83 Mbits
for a one-set sequence.  This program is to be run once, maximum (TBD).

o Program 2c: (From Katsukawa-san.)  SP normal map at a fixed slit position (sit-and-stare).

- # slit positions: 1
- step size: 1
- # cycles: 6 (4.6sec integration)
- extract table: 10 (768pix, ~120" along the slit, twice the size of Venus)
- scan sum: no (normal map)
- spatial bin: 1 (no summing)
- CCD both sides (for reducing dI/dt noise)
- scaling: I only
- repeat ON
- compression: Q75

It is estimated to take ~15mins for the passage of Venus across the fixed slit; this SP program should be run for 30 mins.  It consumes telemetry of 640Mbits for the 30mins scan.  It can be run once or twice.  If it is necessary to reduce telemetry usage of this Program 2c, the following options can be considered:

(1) Use deeper integration (4.8sec->9.6sec)
(2) Reduction of JPEG (Q75 -> Q65)
(3) Reduction of FOV along slit (120" -> 80")


o In the timeline below, there are four time slots with SOT Program 2 (beginning respectively at 22:45, 23:45, 03:02, and 04:20 UT), covering a total duration  of 246 min.   Running 2a approximately once every 180 sec requires ~3.1Gbits. Running 2b once requires ~83 Mbits.  Running 2c twice requires 1.3Gbits. In total then, SOT Program 2  requires 3.1+0.1+1.3 ~4.5Gbits.  Can reduce use of 2a if necessary to save telemetry.


SOT Program 3:  This is run from ~17 before Contact 3, continuing for about 3 min after Contact 3 when Hinode enters s/c night; use highest resolution:

 BFI filter cycle 2k x 2k 1x1 (no summing), Q 95: high-resolution and high-cadence aureole study.
     (focus change(?))
     CN 388.5 nm (repeated five times)
     (focus change(?))
     Blue continuum 450.5 nm (repeated one time)
     Ca H 396.8 nm  (repeated one time; publicity image)

Cadence:  estimated 8-10 seconds between images.



Details of the above programs will be tweaked by the SOT CO (Ted Tarbell) as the upload plan is being developed, based on the latest testing of elements of the code that help to refine telemetry usage and other factors.



----------------



XRT Program 1: Imaging in Al-mesh and Ti-poly.  Deep-as-feasible exposures. Subfield of 2x2 (Ti-Poly) or 4x4 (Al-Mesh) binning.  Dark frames.  This program is used when Venus is outside the limb.

XRT Program 2:  Imaging in Ti-Poly; some Al-Mesh images also likely.  Deep-as-feasible exposures.  Subfield of 2x2 (Ti-Poly) or 4x4 (Al-Mesh) binning.  Dark frames.  This program is used when Venus is on-disk.

Above programs likely to use 384x384 FOV.  Also there should be 512x512 FOV Ti-Poly images at fairly-regular cadence for publicity.

Details of the above program will be tweaked by the XRT CO (Taro Sakao) as the upload plan is being developed.


----------------

EIS Program 1:  Non-disk observations (pre-contact I and post-contact IV);
Acronym - SI_Venus_slit
   Slit observation for Full CCD.
   Exposure 300 sec,  2 arcsec slit,  256 arcsec slit direction
   Sit & Stare.
   data rate=21.94 kBits/s, total 5min39sec

EIS Program 2: On-disk observations;
Acronym - SI_Venus_slot_v1
   Exposure 20sec, 40 arcsec slit, 256 arcsec slit direction
   scan range 200 arcsec
   data rate= 32.27 kBits/s, total 2min40sec

EIS Program 3:  non-disk observations
Acronym - SI_Venus_slot_v2
   Exposure 100sec, 40 arcsec slit, 256 arcsec slit direction
   scan range 2-- arcsec
   data rate= 7.29 Kbits/s, total 3min56sec

-------------------------
-------------------------
ToO Observation Timeline:
-------------------------




------------------
- 20:52:30 XTW_EXIT Start ToV Obs

Pointing = (-710,590)+offset. NE Limb.  R=923.1''


SOT:

No observation.



XRT:

Target: (d), (e), (f) deep exposure

Program: XRT Program 1.  



EIS:

Target: (f) deep exposure

Program: EIS Program 3 at the start, followed by repeated runs of Program 1, and one Program 3 run at the end.  Run repeats of Program 1 as much as telemetry allows, but be sure to include runs of Program 3 at the start and end of the period.


------------------
- 22:01:00 XTW_ENTRY

SOT, XRT, EIS:

No observation



------------------
- 22:06:00 NGT_ENTRY

SOT, XRT, EIS:

No observation




** - 22:15:18.6 ToV First Contact; Hinode in night.  **




------------------
- 22:25:30 NGT_EXIT Between contacts 1 and 2.

Pointing: Unchanged from before


SOT:

Target: (a), (b), (h)


Program: SOT Program 1, cont.  Note: SOT needs focus considerations during
this early post-night period.

XRT:

No observation


EIS:

No observation





** - 22:28:57.9 ToV Second Contact. **







------------------
- 22:31:00 XTW_EXIT Venus on disk.


Pointing: Unchanged from before.

SOT:

Target: (a), (b), (h)


Program: SOT Program 1, cont.  Need good focus for press release.





XRT:

Target: (d)

Program: XRT Program 2.  



EIS:

Target: (f)

Program: EIS Program 2.





------------------
- 22:44:30 Change Hinode Pointing Venus on disk.


Pointing = (-520,546)+offset; Disk Pointing 1.

SOT:

Target: (c), (h)


Program: SOT Program 2.






XRT:

Target: (d)

Program: XRT Program 2, cont.



EIS:

Target: (f)

Program: EIS Program 2, cont.



------------------
- 23:39:30 XTW_ENTRY


Pointing: Unchanged from before


SOT:

Target: (c), (h)


Program: SOT Program 2, cont.


XRT:

No observation


EIS:

No observation




------------------
- 23:44:30 NGT_ENTRY

SOT, XRT, EIS:

No observation




------------------
- 00:04:00 NGT_EXIT

Pointing: Unchanged from before


SOT, XRT, EIS:

No observation




------------------
- 00:09:30 XTW_EXIT

Pointing: = (-137,536)+offset; Disk Pointing 2.

SOT:

Target: (c), (g), (h).  * SOT Obs start at 00:15, following focus
stabilization.


Program: SOT Program 2, cont.



XRT:

Target: (d)

Program: XRT Program 2, cont.  



EIS:

Target: (f)

Program: EIS Program 2, cont.





------------------
- 01:18:00 XTW_ENTRY


Pointing: Unchanged from before


SOT:

Target: (c), (g), (h)

Program: SOT Program 2, cont.



XRT:

No observation


EIS:

No observation




------------------
- 01:23:00 NGT_ENTRY

SOT, XRT, EIS:

No observation




------------------
- 01:42:30 NGT_EXIT

Pointing: Unchanged from before


SOT, XRT, EIS:

No observation




------------------
- 01:48:00 XTW_EXIT


Pointing: = (255,527)+offset; Disk Pointing 3.

SOT:

Target: (c), (h).  * SOT Obs start at 01:53, following focus
stabilization. *



Program: SOT Program 2, cont.


XRT:

Target: (d)

Program: XRT Program 2, cont.  



EIS:

Target: (f)

Program: EIS Program 2, cont.





------------------
- 02:56:30 XTW_ENTRY


Pointing: Unchanged from before


SOT:

Target: (c), (h)


Program: SOT Program 2, cont.


XRT:

No observation


EIS:

No observation




------------------
- 03:01:30 NGT_ENTRY

SOT, XRT, EIS:

No observation




------------------
- 03:21:00 NGT_EXIT

Pointing: Unchanged from before


SOT, XRT, EIS:

No observation




------------------
- 03:26:00 XTW_EXIT


Pointing: = (623,523)+offset; Disk Pointing 4.

SOT:

Target: (c), (h).  * SOT Obs start at 03:32, following focus
stabilization. *


Program: SOT Program 2, cont.


XRT:

Target: (d)

Program: XRT Program 2, cont.



EIS:

Target: (f)

Program: EIS Program 2, cont.


------------------
- 04:20:00 Pointing change.

Pointing: = (750,540)+offset; NW limb.  Limb at R=924.1''


SOT:

Target: (a), (b), (h).



Program: SOT Program 3.



XRT:

Target: (d)

Program: XRT Program 2, cont.  



EIS:

Target: (f)

Program: EIS Program 2, cont.


------------------
- 04:35:00 XTW_ENTRY


Pointing: Unchanged from before


SOT:

Target: (a), (b), (h)


Program: SOT Program 3, cont.



XRT:

No observation


EIS:

No observation



**  - 04:36:29.6 ToV Third Contact.   **



------------------
- 04:40:00 NGT_ENTRY

SOT, XRT, EIS:

No observation


** - 04:48:56.5 ToV Fourth Contact.     **



------------------
- 04:59:30 NGT_EXIT


SOT, XRT, EIS:

No observation




------------------
- 05:04:30 XTW_EXIT


Pointing: Unchanged from before


SOT:

No observation.



XRT:

Target (d), (e), (f) deep exposure

Program: XRT Program 1.



EIS:

Target (f) deep exposure

Program: EIS Program 3 at the start, followed by repeated runs of Program 1, and one Program 3 run at the end.  Run repeats of Program 1 as much as telemetry allows, but be sure to include runs of Program 3 at the start and end of the period.


------------------
- 06:13:30 XTW_ENTRY

End of ToV observations.

HOP list   Monthly Events