Time variations in the RHESSI HXR (20–50 keV) solar integrated flux (green histogram) and HT-MSDP-SECIS Hα fluxes (red histogram) of the K25 flaring kernel recorded during the M1.0 flare in NOAA 10 786 active region on 2005 July 12. The Hα flux were taken  − 0.8 Å from the line centre and are on a linear scale. The RHESSI data are count rates (per second per detector) on a logarithmic scale. The vertical scales indicate the units of each. The integration times are 0.25 s for the demodulated HXR data, and 0.05 s for Hα data. The data were smoothed using a 1-s box-car filter for HXR flux and 0.5-s box-car filter for Hα light curves. The error bars indicate the standard deviations calculated for both light curves. Here and in the next two figures the error bars in the X-ray light curves are plotted on the left, while the error bars of the Hα light curves are plotted on the right.