Example of template matching and RV calculation using a single-exposure spectrum of WDJ084253.03+230025.47 at MJD = 59230.357356. The top panel shows the matching of the normalized spectrum with the best template (T_eff = 27 000 and log g = 8.0). The bottom panel displays the χ² curve and CCF curve obtained by shifting the best template. It can be seen that the RV results from the CCF and χ² curves are very close.