IMHO some older alpha scopes especially if they can be used with modern eyepieces would be comparable to new alpha scopes if you take into account things such as fluorite glass as opposed to ordainary glass with average coatings this however only shows in poor conditions ie when the light is fading I would urge anyone when making comparisions with bins or scopes to avoid sunny days when making a purchase.
As if to proove a point a local place did not like it one bit when I pointed out to a customer they were trying to blag that she would gain insight into the difference between alpha and cheaper bins if she delayed her purchase until a day when the conditions did NOT have such good light.
