6 November–December. In this figure, we can also see the non-synchronous rotation of the F star from its starspot rotation. Since the rotational velocity of the hotter component is very small, the spots on it are hardly resolved and mainly produce the changes of the line strength of the F star at different orbital phases.

Poor phase sampling may lead to artefacts in the reconstructed images. Hence we tested for the reliability of our Doppler images, as discussed in Appendix A (online only). The results indicate that arc-shaped features in all of the surface images of the K star are spurious, especially for large phase gaps, where show pronounced arc-shaped artefacts (e.g. the prominent features at phases 0.4 and 0.8 in 2006 September). In addition, starspots at unobserved phases may be absent in the reconstructed images.

Discussion
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![Images of SZ Psc at phases 0, 0.25, 0.5 and 0.75, of one orbital cycle (HJD2454067.04–2454071.00).[]{data-label="fig:images"}](p00.eps "fig:"){width="35.00000%"} ![Images of SZ Psc at phases 0, 0.25, 0.5 and 0.75, of one orbital cycle (HJD2454067.04–2454071.00).[]{data-label="fig:images"}](p25.eps "fig:"){width="35.00000%"} ![Images of SZ Psc at phases 0, 0.25, 0.5 and 0.75, of one orbital cycle (HJD2454067.04–2454071.00).[]{data-label="fig:images"}](p50.eps "fig:"){width="35.00000%"} ![Images of SZ Psc at phases 0, 0.25, 0.5 and 0.75, of one orbital cycle (HJD2454067.04–2454071.00).[]{data-label="fig:images"}](p75.eps "fig:"){width="35.00000%"}

We have presented the first Doppler images of the cooler component of SZ Psc for 2004 November and 2006 September–December. The surface images indicate significant starspot activities for all of the observing seasons. Starspots on the surface of the cooler component were located at various latitudes and longitudes. The presence of pronounced high-latitude or polar spots was revealed by all of our Doppler images. However, the surface maps do not show large polar cap on the cooler component during our observations, wh