We pursued a long-term campaign aimed at following small active
regions, that could be studied in detail with the
CDS Normal Incidence Spectrometer (NIS).
With the rastering of a long slit, monochromatic images
(plus density and velocity maps) of the field of
view (4¢× 4¢) can be constructed.
Two types of NIS `studies' were used.
- A diagnostic raster (1 hour and 20 minutes)
that extracts many diagnostic lines;
-
a fast raster (20 minutes), but that only extracts a few lines,
selected to cover a wide range of temperatures
(He I 584 Å, log T =4.5; O IV 625.9 Å, log T = 5.3;
O V 630 Å, log T = 5.4; Mg X 625 Å, log T = 6.0;
Si XII 520.8 Å, log T = 6.3; Fe XIX 592.2 Å, log T = 6.9).
The fast raster is normally repeated a few times, to allow
a good temporal coverage of the flare evolution.
