Hi list, Doing my first steps in your world, I am trying to model my data. I am following Kelly's helpful review from 2008 and stuck on apparently simple issue: In order to reduce my deltaE0 (now 9.2), following her advise, I am trying to recall the theoretical spectrum from Artemis to Athena; this was produced by filtering and fitting my data according to the first shell, then fixing all parameters to their best fit, except for enot set to zero, making a sum of all paths under these conditions, saving it as a chi(k) and take it to Athena. Here, to my understanding, I suppose to introduce the 'new-made' chi(k) as a standard and align my data accordingly, save it as a chi(k) and take it back to Artemis to complete the fitting. Unfortunately I cannot make it a standard in Athena, since the whole background options are not available when a chi file is called in. Can someone give a hint? Suggest other ways to better choose E0? Best, Dave