High Temporal Resolution H_α and Off-band Observation on 2B/X1.3 Flare of AR 5047 on June 24,1988

The AR 5047 was the first target active region during the Coordinated Observation Interval Ⅲ (June-July 7, 1988). There were several small flares observed before June 22. But four Xclass flares erupted only in two days of 23th and 24th. Two of them, the 1B/X1.6 flare at 0923 UT on June 23 and the 2B/X1.3 flare at 0422 UT on June 24, were observed by 26cm Solar Telescope at Yunnan Observatory. And the observation of the 2B/X1.3 flare was carried out in H_α and off-band ±0.5Å，±0.75Å，±1.0Å with high resolution(5sec). The time development series of the flare and the sunspot fine struture are shown in Figure 2.