Thanks! I have been building it after a lot of reading, mostly here in SGL. Although choosing eyepieces based on exit pupil seems to be a controversial argument some time, I found that it helped me a lot. Exit pupil, field of view and magnification are the three ingredients of my selection. pan24 -> 4.0mm, 4.3deg, 15x nag13 -> 2.2mm, 2.8deg, 27x nag7 -> 1.2mm, 1.5deg, 51x nag3.5-> 0.6mm, 0.7deg, 103x Knowing that I like F5-F6 telescopes means that the exit pupil is very similar, simplifying the selection. For a dob F6: the exit pupil is the same. ============================= nag13 -> 2.2mm, 0.9deg, 92x nag7 -> 1.2mm, 0.5deg, 171x => a nag 9 covers the hole nicely (1.5mm, 0.6deg, 133x) For a dob F5: the exit pupil increases a bit, but in a nice way (assuming dob10") ============================================= pan24 -> 4.8mm, 1.25deg, 52x nag13 -> 2.6mm, 0.8deg, 96x nag7 -> 1.4mm, 0.4deg, 179x => again a nag 9 covers the hole nicely (1.8mm, 0.6deg, 139x) In summary, as other users reported already, from a medium power (exit pupil 2.0mm) you scale up or down: Basically, exit pupils: 4.0mm -> low power *** 2.8mm -> medium/low power ** 2.0mm -> medium power *** 1.4mm -> medium/high power *** 1.0mm -> high power *** 0.6mm -> very high power * where: ***: very useful ** : useful if the telescope is sufficiently large (e.g. >=200mm) * : useful if small telescope If the eyepieces have same field of view, they work nicely together too. For the scale of exit pupils shown above, from 2.0mm you multiply or divide by 1.4 and you get the other values. To me 1.4 makes a nice perceptible distance.