Data Reduction Frequently Asked Questions
What do I have to take care of if I want to compute the radial velocity of the same target over a certain period of time? And which precision can I expect?
When computing the radial velocity of the same target over a certain period of time, it is important to use the same template (mask_table_id) to remove systematic effects between measurements at different epochs. All calibration and science must be reduced with the same version of the ESPRESSO pipeline; downloaded master calibrations from the ESO archive have not always been processed with the latest pipeline release. With high SNR data, one can expect a relative precision of 50 cm/s. It is, however, recommended to use the interactive features of the ESPRESSO-DAS workflow in order to improve the precision.