CHIPS Solar Science Archive


The CHIPS satellite performed 1458 observations of the Sun from
03 April 2006 to 05 April 2008,
a period of generally declining activity following the solar maximum of 2001.
The satellite was decommissioned on 14 April 2008.
Typical observations ranged from 1 to 15
minutes which yielded spectra of  roughly $10^5$ total counts each.
Occasionally, up to 15 such observations per day were performed.
However for a variety of causes, including passages through the
South Atlantic Magnetic Anomaly, passages through the electron belts at
high magnetic latitudes, targets of opportunity, precession of the orbit
into full sunlight, and satellite shutdowns, the cadence of observations
is far from uniform.
The data are presented and analyzed in the Journal of Solar Physics
(Sirk, Hurwitz, and Marchant 2010).
Any use of these data should acknowledge this paper.

For convinience an ASCII catalog of all observations is available in
Solar_Obs_Catalog.dat.
The 9 columns list the filename, the starting and ending times in
Reduced Julian Day, the duration of the observation in seconds (s), the number
of days since 2006:00:00:00 GMT, the deadtime corrected exposure time (s),
the error in the exposure time (s), the contamination fraction, and the
scale factor to convert CHIPS flux to XPS4 flux. 
See the article above for further details.
The quality of the observations varies considerably. As a general rule,
observations with very short exposure times, or very large dead-time
corrections have greater uncertainty in the flux.
Observations with contamination fractions
of less than 0.12 are very good, 0.12 to 0.20 are good, 0.2 to 0.3 are OK,
and greater than 0.3 should be used for qualitative purposes only.

Each observation is stored as a five column FITS file containing
Wavelength, Al Counts, Zr Counts, Al Flux, and Zr Flux (erg/sec/cm^2/Ang).
The wavelength array ranges from 150 to 275 Ang in 0.1 Ang steps.
The flux below 170 Ang in the Al filter is second channel contamination
and scattered light, not real spectral features.
The Zr filter data shows a few Ni features below 170 Ang.

------------------------------------------------------------------
For example, to load a spectrum, use the IDL ASTRO routine mrdfits

a = mrdfits('al_cool_counts_erg_flux.fits',0,h)

lambda    = a[*,0]
Al counts = a[*,1]
Zr counts = a[*,2]
Al flux   = a[*,3]
Zr flux   = a[*,4]
------------------------------------------------------------------

We present raw spectra integrated over the two-year period for
the upper Zr/Al filters, and the lower large Al filter in
raw_spec.png
The brightest features are from Fe IX through Fe XV.
Also evident is a continuum of in-band scattered light
from the diffraction gratings superimposed with second (and possibly
third) channel features (see Sirk et. al. 2010),
which occur more frequently, and to a greater degree, in
the upper Zr/Al filter.
Particle background (primarily high energy electrons) is
negligible as evinced by the near zero count rates in
the shadows of the filter frames. 

Journal of Solar Physics Paper
Solar Observations Catalog 
Directory of all 1458 observations
Raw Aluminum and Zirconium Spectra