Study 000379:

ACRONYM:  YKK_EqCHab_01N

This study is one of the two studies designed for measuring temperatures,
densities, and abundances in and at the boundary of equatorial, low-latitude
and polar coronal holes that may correspond to different footpoints of the
fast to slow solar wind. 

To improve the signal in weak lines, 2 long exposures are taken at each
position in the raster.

TARGET: Coronal Hole

EXPOSURE TIME: 150s x 2 (2 exposures per raster position)
RASTER: Scanning
SLIT: 2"
STEP SIZE: 2"
FOV: 50"x400"
RASTER DURATION: 2h16m13s
COMPRESSION: DPCM
VOLUME: 65 Mbits

Pointing:

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Targets:

1) An equatorial or low-latitude coronal hole (within 40 degrees to the
   solar equator)
2) Polar coronal hole can also be a candidate of study especially if it
   extends to below 40 degrees in latitude. 

Detailed pointing:

The raster field-of-view should at least cover the solar equator or 
if the coronal hole does not reach latitude zero, the lowest latitude
that the coronal hole covers. The best time for observing is around its
passage across the central meridian.  For a polar coronal hole without
low-latitude extension, point at the central meridian with
raster FOV covering partly the coronal hole, partly the quiet Sun.

Use/Instructions to planners:
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The objective of this study is the variation in physical
properties (temperature, density, abundances) along the LONGITUDINAL extent
of an equatorial, low-latitude or polar coronal hole that may correspond
to different footpoints of the fast to slow solar wind. Therefore the
longitudinal coverage is essential.

This raster is used in combination with another study YKK_EqCHab_01W to
complete a set of observations on the coronal hole and its EAST boundary. A
default set of study is as follows.

a) Run this study YKK_EqCHab_01N (twice), one near the center of the coronal
   hole, the other in between the center and the EAST coronal hole boundary.  

b) Run the study YKK_EqCHab_01W (once) at the EAST boundary of the
   coronal hole, partly covering the 'visible' coronal hole, partly covering
   the neighboring active region or quiet Sun at its east. 

c) Follow step b) by one context raster study (PRY_slot_context_v3,
   or PRY_slot_contextLITE if the available telemetry is tight) covering
   the FOV of the above raster runs. 

The two studies (YKK_EqCHab_01N and YKK_EqCHab_01W) can be used in
various combinations depending on the coronal hole size or planning
restrictions. At least three raster runs like the above default set on one
given coronal hole are requested in order to meet the objectives of the study.
If not possible, the priority is

1) East coronal hole boundary
2) In between the center and the EAST coronal hole boundary,
3) Center of the coronal hole.

The pointing of multi-raster runs should be made in a sequence toward the EAST
(i.e. from the center of the coronal hole toward its east boundary). 

The FOV (relative to the CH) of the series of raster scans should not overlap.

Warning:
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None.