Top-left panel: C_{F275W, F336W, F814W} vs m_F275W − m_F438W pseudo-CMD of the HB stars in NGC 2808. The stars with T < 11 500 K, T > 18 000 K, and 11 500 K < T < 18 000 K are marked with orange, blue, and red points to show the location of the G- and M- jumps. Top right panel: m_F275W vs m_F275W − m_F814W CMD of the HB stars in NCG 2808. Bottom-right panel: Histogram of the colour distribution of the photometric data. The cumulative distribution of the points is plotted as the purple profile. The dashed lines in the panel, green and cyan, represent the position in m_F275W − m_F438W of the G- and M- jumps, respectively. Bottom-right panel: m_F438W vs m_F438W − m_F814W CMD of the HB stars in NCG 2808. The colour coding of the points highlight the temperature ranges of the stars where applicable.