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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0225

Transit of Venus as Seen from Saturn (SToV), 2012 December 21.

plan term


@ @


 name : Pasachoff, Schneider, Reardon, Sterling @  e-mail : alphonse.sterling[at]nasa.gov

contact person in HINODE team

 name : Sterling @  e-mail : alphonse.sterling[at]nasa.gov

 abstract of observational proposal
As viewed from Saturn, Venus will transit the Sun on 2012 December 21, for about 11 hours.  The Cassini spacecraft will observe the Sun from Saturnian orbit during the transit.  Venus and Saturn however are positioned on the other
side of the Sun from  Earth on this date, and only the first ~2.5 hours of the event will occur where the projected location on the Sun of the  extension of Saturn-Venus line visible from Earth; we refer to the projection on the solar
surface as the ``footprint'' on the Sun of the Venus-as-seen-from-Saturn track.  This  proposal is for Hinode SOT observations to support the Cassini study by observing with high resolution this Venusian footprint location on the

The potential Hinode observations will be restricted to times if and when this footprint crosses the expected location of plage or active regions.  Major Flare Watch observations or other key Hinode observations or activities have a
higher priority than these SToV observations.

The location of the SToV footprint as seen from Hinode has been provided by plan team member G. Schneider, with calculations done by Jon Giorgini of JPL.  The SToV footprint will be  visible from Hinode on 21 December 2012, 11:10-13:30 UT.  On that day, Venus as seen from Earth  will be ~11'' in diameter, and hence this is the angular size of the deprojected SToV footprint of Venus.  Using this information, and assuming an SOT FOV of about 200'' X 100'', we  have determined the needed pointings for the period of time.  That information is given in the  Remarks section below. Plan team  member A. Sterling will attend the relevant Hinode morning meetings to assist with the planning.

The detailed content of these observations is very similar to that of the Jupiter ToV (JToV) observations of 20 September 2012, described in HOP 218.  The next planetary transit of this nature will be a transit of Earth as seen from Jupiter (JToE), 5 January 2014.

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

Filters and programs:

- A minimum image sequence in Ca H (3968 Ang), G-band, and red continuum channel is requested.   We expect the G-band and Ca filters to show well features such as brightenings and sunspots.

- As a minimum, two or three sequences per pointing are requested.  These can be varied as telemetry  and other plans permit.  If time is available, relatively continuous coverage at low cadence can be run.  Lossless compression has been requested, and should be considered if telemetry permits.

- Synoptics can be run as normal.

 request to XRT
No request.

 request to EIS
No request.

 other participating instruments
- Cassini

- Pointing number, Time period (UT time on 21 Dec 2012), and Pointing-Center location:

(1)  11:10 -- 11:20 UT:         X=  +600.0"       Y= -375.0"
(2)  11:20 -- 11:45 UT:         X=  +725.0"       Y= -375.0"  
(3)  11:45 -- 13:30 UT:         X=  +850.0"       Y= -390.0"  

SOT/SC offset is not accounted for with these values.  It should be accounted for when generating the pointing table for the upload.

- Pointings should be considered when there is a possibility for the SOT FOV to cross active region or plage locations.

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