SECCHI HI Level 2 FITS files produced by the UK Solar System Data Centre, calibrated and background subtracted. Images stored in FITS files with filenames such as "20140101_180501_24h1A_br11.fts". The meaning of the different parts of this filename is as follows:

• 20140101 is the observation date, 2014-01-01;
• 180501 is the observation time, 18:05:01 UT;
• 2 represents Level-2;
• 4 is a code for the data units, where 4=Dn/Sec/Pixel, b=Mean Solar Brightness (MSB), and t=S10. MSB & S10 have the diffuse source correction applied;
• h1 or h2 for HI-1 or HI-2;
• A or B for STEREO-A or STEREO-B;
• br for Buffinton/RAL background subtracted--a full running window where the F-corona is computed as the mean of the lowest quartile of pixels;
• 11 is the length of the running window in days, usually either 01 or 11 for HI-1, and 03 or 11 for HI-2.