Interesting concept, and well thought out.
a) I think some sort of superpolish is going to be necessary for planetary due to the SP reducing scatter which no coatings can do.
b) I think you can pull this off with 3 EPs and 3 Barlows 1.5, 2.25, and 3.35
1.5 2.25 3.35
17.5 11.67 7.8 5.21
20.0 13.33 8.9 5.96
22.5 15.0 10.0 6.70
Probably right on the polish issue. We always hear off-hand comments from people about the cost of the next level of polish. Would be interesting to hear from a current producer of eyepieces how much their costs to the consumer would rise on a particular eyepiece brand it they requested the next level of polish. Would be nice to hear from the horses mount based on current day pricing from their suppliers.
On the Barlows, my only issue is having to figure out in the field what BArlow with what eyepiece gets me the next magnification increment. Right now when I design a series like this I make sure that whatever focal lengths I biring out that after I get to the shortest I just put the Barlow in and it stays in and I recycle through the series in sequence. So no fuss no muss no thinking So as example, when I bring out the XWs I will often just take the 20, 14, and 10 plus a 2,5x Powermate for 8, 6, and 4. Makes life easy. Yours seems to do that but wow...3 different Barlows
Edited by BillP, 30 May 2020 - 12:23 PM.