1st Op vs. 2nd Op lathe

[canonicalman]

I was looking at the Hardinge lathes for sale on ebay. Many were descibed as either 1st Op or 2nd Op. What are the differences between the two? And would either be of use as a general use high precision lathe?

[Rustybolt]

Hardinge's second operation lathes are small turret lathes(turret tailstocks).These are usually Dv designations. Unless you do production they're not very useful for home machinists. They are ,however, extremely accurate.They also have a production lathe with a turret cross slide(HS designation?)
which is the heavier of the two and would be more useful in a home shop environment.