HOP 0368

abstract of observational proposal

Main Objective: Magnetic field measurement in the chromosphere

Scientific Justification:
Following the success of CLASP, we are going to have its second flight, CLASP-2 (Chromospheric LAyer SpectroPolarimeter 2), which will measure the four Stokes profiles across the Mg II h and k lines around 280 nm. CLASP-2 aims at measuring the circular polarization induced by the Zeeman effect in such resonance lines as well as the linear polarization caused by the joint action of scattering processes with magneto-optical effects and the Hanle effect. The CLASP-2 spectropolarimetric observations will help us to better constrain the magnetic field in the upper chromosphere.

We are planning to have coordinated observations with IRIS, Hinode, and some ground-based telescopes. In particular, the IRIS spectroscopic observations of the Mg II lines will provide information on the dynamics of the observed targets.

The CLASP-2 launch is scheduled for April 1 of 2019, and the current launch window is 17:05 - 17:45 UT.

We will have 3 targets during our ~5min flight, but we request coordinated observations of a plage before and after as well as during the flight. The exact coordinates and the launch time will be determined and communicated before the planning.

request to SOT

(Case 1, if the CLASP-2 slit is almost parallel to the north-south direction)
-2 hours ~ -1 hour : 1 context map for QS (obs A)
-1 hours ~ start of launch window : 1 context map for plage (obs A)
launch window (roughly 1 hour) : repeat high-cadence scans (obs B)
end of launch window ~ +1 hour : 1 context map for plage (obs A)
+1 hours ~ +2 hour : 1 context map for QS (obs A)

(Case 2, if the CLASP-2 slit has an angle of more than 15 degrees)
-2 hours ~ -1 hour : 1 context map for QS (obs A)
-1 hours ~ launch window ~ +1 hour : repeat context maps for plage (obs A')
+1 hours ~ +2 hour : 1 context map for QS (obs A)

obs A: single scan with fast mode, 320" x 160" (2048 slit positions and 1024 pixel high), 2x2 binning, single side mode for context map

obs A': repeat scans with fast mode, 320" x 160" (2048 slit positions and 1024 pixel high), 2x2 binning, single side mode for context maps

obs B: repeat scans with fast mode, 5" x 164" (32 slit positions and 1024 pixel high), 2x2 binning, ~1 min cadence (2 cycles (1.6 sec) at one slit position), single side mode

other participating instruments

IRIS requests:
OBS ID = 3623101440
roll angle requested if possible

Updated IRIS observations (2/20/2019):
LS = launch window start
LE = launch window end

LS -70 min: 2 repeats on plage target:
3620106077 | Very large dense 320-step raster 105.3x175 320s Deep x 4 Spatial x
2 | 1657.36 | 2051.85 | 0.8 | 5.2+/-0.1 | 1657+/-0 | 20.7+/-0.0 | 20.7+/-0.0 | 20.7+/-0.0 |20.7+/-0.0

LS-10 min through LE+10 min: repeat on plane target:
3683603440 | Very large sparse 16-step raster 15x175 16s Si IV Mg II h/k Deep
x | 28.37 | 144.90 | 3.5 | 1.8+/-0.1 | 28.1+/-0.1 | 0.0+/-0.0 | 3.5+/-0.0 | 3.5+/-0.0| 0.0+/-0.0

LE+10 min: 2 repeats on plage target:
3620106077 | Very large dense 320-step raster 105.3x175 320s Deep x 4 Spatial x
2 | 1657.36 | 2051.85 | 0.8 | 5.2+/-0.1 | 1657+/-0 | 20.7+/-0.0 | 20.7+/-0.0 | 20.7+/-0.0 |20.7+/-0.0

DST (IBIS), GST (VIS, TiO, NIRIS)

remarks

Dates: 2019/04/01
Time window: 17:05 - 17:45 UT
Target(s) of interest: Plage as primary, quiet Sun as secondary
Additional Remarks: We will have 3 targets: DC, QS near the limb, and plage. The primary coordination is for the plage, but we would also like Hinode to obtain context maps of QS. Hence, we request pointings as follows:
-2 hours ~ -1 hour : QS
-1 hours ~ launch window ~ +1 hour : plage
+1 hours ~ +2 hour : QS
Total Hinode observation time of 4 or 5 hours including the launch window.

Previous HOPs: HOP 290