I am thinking about buying a single stacked H alpha scope from a local Lunt vendor here in Sweden - the internal etalon in the model he has in stock comes with a small tuning knob right above the Lunt label.
This is different than the (I think) more recent pressure tuned single internal etalon versions.
My question is: how well does this scope perform visually, and can it be double stacked later???
I need to give the vendor a decision soon if I wan this scope or not
Thanks for speedy answers