Upgrading the Terminal System on the Fine-structure Heliograph at Gan-Yu Station of Purple Mountain Observatory and Some New Observational Results

摘要

In order to observe the bombardment of the solar chromosphere by high-speed electrons from flares, the fine-structure heliograph at Gan-Yu station of Purple Mountain Observatory has been upgraded to a high-speed CCD instrument that takes Hα filtergrams of solar local active regions. A focal reducer is added to the original optical system, and after introducing the polarization interference filter, the Hα filtergrams at different wavebands can be obtained by the fast CCD terminal. After repeated tests and improvements during the years 1999–2004, the upgrading is now completed with good result: the spatial resolution reaches 1 arcsec, and the temporal resolution is 30–40 frames per second.