So you buy your first refractor. You're out on the field or backyard finally getting ready to test all your eyepieces that you've been comfortably using with your other type of scope all these years.
You insert a 40mm 70º and wonder why you can't achieve focus, thinking you need a few more mm of infocus, no big deal, try another one for now. You put in the 31.5mm 90º, perfect, with lots of infocus left. You step down to a 25mm 100º, same story as the 40mm, it needed a few more mm to reach focus.
You try a 20mm 100º, same story, next, 17mm 102º again same story, 12mm 92º this one works perfectly. A 9mm 101 and 5mm 110 work fine too. All 1.25" Pentax and Delos can't reach focus. The night pretty much ends up in a kind of frustrating way. Besides a great view of the Beehive.
Sure, I'm using a 2" Baader Clicklock Diagonal with 112mm of lightpath with an Orion Astroview Deluxe 600mm f/6 refractor, but how am I supposed to know what scope works with what eyepiece and diagonal?
Are there stats anywhere for knowing about which eyepieces will focus with which refractors? I read now in a few scattered posts that it has to do with focal points and planes and which eyepiece has them closer to the lens, but how does someone to know which eyepieces have them where? How much backfocus or total focus space does my scope even have? I looked in the manual, garbage, nothing written. Do some refractors have a longer infocus travel mechanism? Am I lacking more infocus or outfocus for the 1.25"? I know all the 2" ones needed more infocus.
I'm not cutting up my scope tube thing neither buying a new 2" diagonal either.
Do you guys know of any nice 2" eyepieces in the 15-24mm and 35-40mm range that would reach focus with this scope? And will a TSFLAT2 work with them?
PS> I tried all eyepieces with and without the TSFLAT2.
Edited by Procyon, 15 April 2025 - 07:12 PM.