  This paper reports X-ray spectral observations of a relatively nearby z =
0.048 BL Lacertae (BL Lac) object 1ES1959+650, which is a potential TeV
emitter. The observations include 31 short pointings made by the Unconventional
Stellar Aspect (USA) Experiment on board the Advanced Research and Global
Observation Satellite (ARGOS), and 17 pointings by the PCA on board the Rossi
X-ray Timing Explorer (RXTE). Most of these observations were spaced by less
than 1 day. \es was detected by the ARGOS USA detector in the range 1-16 keV,
and by the PCA in the 2-16 keV range but at different times. During the closely
spaced RXTE observations beginning on 2000 July 28, an ending of one flare and
a start of another are visible, associated with spectral changes, where the
photon index Gamma ranges between ~ 1.4 and 1.7, and the spectrum is harder
when the source is brighter. This implies that 1ES1959 is an XBL-type blazar,
with the X-ray emission likely to originate via the synchrotron process. The
USA observations reveal another flare that peaked on 2000 November 14 and
doubled the flux within a few days, again associated with spectral changes of
the same form. The spectral variability correlated with the flux and timing
characteristics of this object that are similar to those of other nearby BL
Lacs, and suggest relativistic beaming with a Doppler factor delta > 1.6 and
magnetic fields of the order of a few mG. We also suggest that the steady
component of the X-ray emission -- present in this object as well as in other
XBLs -- may be due to the large-scale relativistic jet (such as measured by
Chandra in many radio-loud AGN), but pointing very closely to our line of
sight.
