We surveyed the central part of the globular cluster NGC 288 for
a total of 64 hours and identified 3 new variables.
Of particular interest is the discovery of a contact binary
which is located slightly above the upper main sequence of the
cluster. Very few main sequence binaries are known for a moment
in the whole sample of galactic globular clusters.
The remaining 2 of newly discovered variables
are pulsating blue stragglers of SX Phe type. There are 6 known stars
of this type in NGC 288.
It is interesting to note
that for 3 of them light amplitudes in V are smaller than 0.10 mag.
This is a bit unexpected because two recent lists of SX Phe stars
(McNamara 1995; Nemec et al. 1995) contain
only one object with AV<0.10 mag. At the same time,
the recent survey of 
Cen leads to identification of 43 SX Phe
variables of which 26 show amplitudes 
mag
(Kaluzny et al. 1996, 1997).
Based on a comparison of a sample of SX Phe stars discovered
in Cen and
in NGC 288 with a sample of field and cluster objects
(McNamara 1995) we arrive at the conclusion that the later sample is
significantly incomplete as regards the variables with low amplitudes.
The Pop I counterparts of SX Phe stars are 
Sct variables.
Variables with amplitudes as small as a few hundreds of magnitude
prevail in the sample of bright Sct stars
(Halprin & Moon 1983). We predict that the currently conducted
surveys of nearby clusters will result in the discovery of
many SX Phe stars with very small amplitudes.
Our data indicate fast changes of pulsation period for
the RR Lyr star V3.
Acknowledgements
This project was supported by the Polish KBN grant 2P03D00808 to JK and by NSF grant AST-9528096 to Bohdan Paczyński. We thank Dr. Xinjian Guo for providing us with equatorial coordinates of stars from the NGC 288 field.