Tweak projection calculation; differentiate rv handling
Tweak projection calculation; differentiate rv handling

aleksandr-bakanov/astropy,saimn/astropy,astropy/astropy,StuartLittlefair/astropy,saimn/astropy,dhomeier/astropy,saimn/astropy,StuartLittlefair/astropy,mhvk/astropy,dhomeier/astropy,larrybradley/astropy,astropy/astropy,lpsinger/astropy,astropy/astropy,aleksandr-bakanov/astropy,aleksandr-bakanov/astropy,mhvk/astropy,lpsinger/astropy,saimn/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,pllim/astropy,larrybradley/astropy,astropy/astropy,pllim/astropy,pllim/astropy,pllim/astropy,lpsinger/astropy,dhomeier/astropy,StuartLittlefair/astropy,pllim/astropy,larrybradley/astropy,StuartLittlefair/astropy,astropy/astropy,saimn/astropy,mhvk/astropy,larrybradley/astropy,mhvk/astropy,StuartLittlefair/astropy,mhvk/astropy,lpsinger/astropy,lpsinger/astropy,dhomeier/astropy,dhomeier/astropy