add test of parallax in distance
add test of parallax in distance

pllim/astropy,saimn/astropy,lpsinger/astropy,aleksandr-bakanov/astropy,dhomeier/astropy,mhvk/astropy,stargaser/astropy,MSeifert04/astropy,larrybradley/astropy,astropy/astropy,saimn/astropy,MSeifert04/astropy,larrybradley/astropy,DougBurke/astropy,stargaser/astropy,dhomeier/astropy,bsipocz/astropy,aleksandr-bakanov/astropy,StuartLittlefair/astropy,dhomeier/astropy,astropy/astropy,MSeifert04/astropy,bsipocz/astropy,lpsinger/astropy,pllim/astropy,stargaser/astropy,mhvk/astropy,mhvk/astropy,astropy/astropy,aleksandr-bakanov/astropy,StuartLittlefair/astropy,dhomeier/astropy,astropy/astropy,mhvk/astropy,larrybradley/astropy,mhvk/astropy,aleksandr-bakanov/astropy,larrybradley/astropy,lpsinger/astropy,lpsinger/astropy,saimn/astropy,DougBurke/astropy,DougBurke/astropy,pllim/astropy,lpsinger/astropy,funbaker/astropy,saimn/astropy,dhomeier/astropy,astropy/astropy,funbaker/astropy,stargaser/astropy,StuartLittlefair/astropy,bsipocz/astropy,pllim/astropy,funbaker/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,bsipocz/astropy,funbaker/astropy,saimn/astropy,larrybradley/astropy,MSeifert04/astropy,pllim/astropy,DougBurke/astropy