I am sure that this topic has come up before, but after failing to get results on my search, I thought that I would post this question.
If I want to do exclusively narrow band astrophotography and want a dedicated refractor to do so, would it make sense to avoid the multi-element corrected (and expensive) APO telescopes and get a single element telescope instead? After all, I would not be asking this rig to focus photons of widely dispersed wavelengths onto a single spot. Also, I am assuming that a single element refractor would lose less light to absorbtion and be more efficient. Are there any high quality such scopes out there for this purpose, or is this now entering the domain of amateur telescope (lens grinding) building? Not looking to settle for a 50mm f15 single element cheapo rig.