I'm pretty new at astronomy, and not totally knowledgeable about relevant optics....but, can anyone tell me why
- I can't focus my refractor using an eyepiece straight through the back (i.e., no diagonal), but...
- I can focus my mak using an eyepiece straight through the back, insead of using the flip mirror.
The refractor is a 80mmED.
The mak is a Vixen 110mm.
Would an "erect image" device make a difference? (I really don't know what they are, but I see them listed on dealers' websites)
Thanks for any help......