sorry for later reply
yes, any CS lens is suitable for ASI120 and C lens is suitable for ASI174 (need a CS adapter)
have a look at here:
http://zwoug.org/viewtopic.php?f=21&t=1878
More questions
So does that mean I can't use my Nikon lenses and I will have to buy a CS Lens for my ASI120 or if I purchase a ASI174 I will have to buy a C lens
What lenses are CS and what lenses are C
I have one of these if that's any help
http://www.ebay.com.au/itm/Baader-C-Mount-for-Nikon-Lenses-2958535-/121235534406?pt=LH_DefaultDomain_0&hash=item1c3a337246
Alan