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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0280

Coordinated Hinode/XRT, SOT and ground based observations of the total solar eclipse of 20 March 2015

plan term


@ @


 name : 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
There are three components to this plan: (1) XRT full-disk observations, (2) XRT limb observations, and (3) SOT limb spicule observations.

(1) XRT full-disk observations. We will combine Hinode XRT coronal observations with white-light observations of the corona obtained from the ground at Svalbard, Norway (and elsewhere, weather permitting).  We will use these images to compare longer-lived X-ray coronal structures  (including coronal cavities and polar plumes) with those structures seen in ground-based data; this type of study between ground-based and space-based observations was recently carried out for the 2012 eclipse (Pasachoff et al. 2015, ApJ,  800, 90), and is in progress for the 2013 eclipse.  The availability of images in multiple XRT filters will allow for X-ray-temperature diagnostics of such structures.  (XRT has reduced spatial resolution for full-disk images, but it should still be adequate for obtaining general diagnostics of large-scale structures, such as coronal cavities.)  Images taken during typical synoptic sequences should be adequate for this program, but as a minimum we require images in Al_poly and Al_mesh filters; we have found this pair to be useful for determining diagnostics of XRT polar coronal hole features (Pucci et al. 2013, ApJ, 776, 16).

(2) XRT limb observations.  One objective is to observe X-ray polar plumes, and compare them with white-light plumes seen from the ground.   We will also look for X-ray jets, to see whether they tend to occur at the base of plumes that are dense enough be appear in the white-light images.  These observations require time series images at the solar limb. Our first-priority target is a polar coronal hole (PCH).  If that is not available, then additional targets are a coronal cavity, a streamer and/or polar quiet Sun.  Again as a minimum, the filters used should include Al_poly and Al_mesh.

(3) SOT observations.  Ca II spicule limb observations during at least one of the periods of the limb studies, preferable during PCH observations.  If no PCH is available, then the preferred target is polar quiet Sun.  The objective is to study spicules at the base of coronal plumes, and/or at the base of X-ray jets (Sterling, Harra, & Moore 2010, ApJ, 722, 1644).

 request to SOT
- Observation plan 3: SOT observations of spicules at the solar limb.

A Ca II sequence capable of observing spicules with medium cadence (~15---20 sec, 2x2 binning  OK).  To be run during limb PCH pointing period.  (If no PCH is available, this should be run on  polar-region quiet Sun, after completion of HOP 278 pointing requests.)

Pointing should be as close to limb as possible (15'').

 request to XRT
- Observation plan 1:

We require two sets of full-Sun images within three hours on either side of totality.  The objective is to have full-Sun XRT images to compare with the totally-eclipsed corona, before and after  the times of ground-based totality.  (The time of the total eclipse on the ground is 10:12 UT.) The images could be obtained with a typical XRT synoptic observation sequence, but as a minimum images in two filters, Al_poly and Al_mesh, are required.  One of these sets of images should be obtained prior to the ground-based eclipse, and another after the ground-based eclipse, as allowed by the the HOP 278 EIS observations. (So if there is a cavity, then the synoptic should run before and after the HOP 278 EIS cavity observations.

If there is no cavity, then the synoptic should run before and after the HOP 278 EIS Streamer/AR observations.)

- Observation plan 2: XRT observations at the solar limb.

TARGET: First choice is a PCH.  If no PCH is available, then target should be quiet-Sun polar region (see TIMING).

TIMING:  Same as EIS request for HOP 278.  If no PCH is available, this observation should additionally run for >~ 1 hour on polar quiet Sun region, after the EIS-requested runs are completed.

FIELD OF VIEW: 512x512 desired (384x384 acceptable)

EXPOSURE TIME: Long exposure time (AEC setting = 2)

FILTERS: Al/poly, Al/mesh, and Ti/poly.

[Note:  Here we request Al/mesh, while HOP 278 requests Thin/Be.  We have talked with the HOP 278 team, and they agree to switch to Al/mesh in place of Thin/Be in their HOP 278 program.]

CADENCE: About 30 seconds between images would be fine, but could be slower (~1 min) if required by planning constraints.

 request to EIS
[This is to be combined with that of Habbal and Landi, HOP 278, which has a detailed EIS request.]

 other participating instruments
Ground-based total eclipse observations will be obtained by Jay Pasachoff and colleagues from Svalbard, Norway, and other locations (weather permitting).

- If there are telemetry concerns, SOT observations are lower priority than XRT (and HOP 278 EIS requests).

- A similar program (with different XRT filters) was requested in HOP 224 for the total solar eclipse of 13 November 2012.  The COs may want to refer to that HOP, but they should keep in mind that that run was *not* successful because: (1) XRT data were out of focus due to an SEU, and (2) SOT pointing was too far from the limb to see spicules.  So for this HOP run, the XRT COs may want to confirm image quality as late as practical prior to the eclipse upload, and the CP should check that SOT's pointing is centered as close as possible to the limb (likely 15'' inside of the limb) during the limb-pointing periods.

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