Open loop (no guiding, no PEC, no KING refraction correction), periodical error is +/- 1 arcsec as shown in the following plot. The curve has been corrected from linear drifts.
Open loop (PEC activated left , PEC and KING refraction correction enabled, right), periodical error is +/- 1 arcsec as shown in the following plot. MCMT drives controlled by PRiSM Software have been used.
A slight KING overcorrection is visible. KING is bound to atmopheric and pressure effects... which could vary from a day to another. The periodical error is almost cancel out by enabling PEC correction.
This is a 300sec
exposure time with PEC and KING enabled (MCMT and PRISM control), raw CCD image,
sampling = 0.8 arcsec/pixel.This an UNGUIDED image !
TBD
TBD