Hello again,  I've done some calculations about the size of the secondary (i think it's 47mm) and i'm thinking of replacing it with a 58mm one to illuminate better the aps size chip of my canon. The central obstruction will go from 13% to 20% but i also want to remove 2cm from the focuser's tube or push the primary up to protrude less in the ota (more light and no D shaped stars). In this way i think the amount of light hitting the primary will be slightly more so there will be no decr