HOP 0236

abstract of observational proposal

coordinated observing campaing using the Swedish Solar Telescope on La Palma, IRIS and Hinode is scheduled for August 25 - October 3, 2013. Observers at the SST will be from Oslo and LMSAL for this entire period. The goal is to obtain very high cadence, high spatial resolution observations of the photosphere & chromosphere with CRISP to accompany the IRIS spectra and images of the chromosphere and transition region. CRISP data will allow measurement of line profiles for Doppler shifts and polarization for some magnetic field information above the photosphere. Hinode will contribute precise photospheric fields with SOT/SP, magnetogram evolution with SOT/NFI and coronal images and spectra with XRT and EIS.

IRIS will be executing its initial "60-day science plan" throughout most of this time period. The IRIS 60-day plan has a variety of targets: AR sunspot, AR plage, QS, CH, filament on disk, and AR, QS, CH, prominence at the limb. This constitutes 9 different targets. In the 60-day plan these targets are observed repeatedly, but at varying mu angles, usually every few days. The goal should be to get decent datasets for all of these different targets, in order of priority. The exact priority order is to be determined, but limb observations are initially lower priority than disk observations given the extreme difficulty of obtaining good datasets at the limb from the SST.

The best coordination time is from 9 am to noon La Palma time, which is 08 UT to 11 UT. During this La Palma time (8 to 11 UT), IRIS will focus on high cadence runs, such as sit-and-stare, small or medium rasters. The typical observing plan for the 60-day-plan is to dwell on one target for many hours, e.g., an active region, with a variety of shorter (typically 1 hour) observing programs during this time. The IRIS planner would typically schedule large raster scans for context before or after the La Palma time, so that high cadence programs are run during La Palma time. Additional IRIS observations during its SAA-free time (11-17 UT) could be of either type but would remain on the same target, for coordination with Hinode.

other participating instruments

IRIS: the IRIS planner must submit his/her plan by 19 UT on Mondays - Fridays; the Friday plan runs for 3 days. No changes whatever are possible after ~21 UT of each weekday. The IRIS planner will announce the target type (one of the above list) for each day's observing in the 8-17 UT period at least 2 days in advance, so the Hinode daily meeting can plan to coordinate with suitable programs. The planner will also indicate the approximate times in which IRIS will be doing large-area rasters, and the times for small-FOV high-cadence programs. More specific pointing information will be provided in time for the Hinode daily meeting before uplink.

SST: the observers at the SST will follow the IRIS target every day, at least during the prime observing time of 8-11 UT, and often during the extended time of 11-17 UT.

remarks

Comparing the planning schedules for Hinode and IRIS reveals that certain time periods during the week are most promising for coordinated observations. For a normal Hinode week, these are 10-17 UT on Tuesday, Thursday and Saturday, which are nearly SAA-free for both satellites; and 8-17 UT on Wednesday, Friday and Sunday. We request that Hinode give priority to IRIS collaboration in these 6 time periods. When Hinode has to make other observations during the SAA-free time, such as HOP 81 or HOP 130, they should be on a Monday, Wednesday, Friday or Sunday.

The periods 8-11 UT on Wed, Fri & Sunday are the most promising for good seeing at SST and Hinode observing, with targets chosen < 1.5 days earlier and no interruptions by uplink of the next Hinode plan. The periods 10-17 on Tuesday, Thursday & Saturday are SAA-free for both Hinode and IRIS and have target coordinates chosen only 0.5 days earlier, so accurate targeting is more likely. 8-10 on Tuesday, Thursday & Saturday have "stale" target coordinates and interruptions, so coordination is less important (but may be tried occasionally by SOT) in those periods.