... The HST standard star observations peating each was carried o tion. standards list (Persson et al. 1998) and the IRIS list (Carter 1995) were used. 6 to 7 standard star were observed per night, whenever possible restandard up to 3 times. ...
... They also suggest that non-standard photometric passbands, such as those from the WFPC2 on HST, Hipparcos and MACHO, can be accurately calibrated from synthetic spectra. ...
... The close similarity is obvious. As shown by recent HST images (Thomson et al., 1995) this close match continues down to even much smaller scales. ...