Data on Time and Polar Motion; Immediate Accessirility

Users o f t ime and p o l a r mot ion i n f o rma t i on have requi rements f o r da ta which a re somewhat d i f f e r e n t f rom those u s u a l l y cons idered f o r ast ronomica l da ta f i l e s . Because o f these requirements. i t i s necessary t o p rov i de immediate access t o t he l a t e s t i n f o rma t i on on Ear th o r i e n t a t i o n and even p r e d i c t i o n s o f f u t u r e o r i e n t a t i o n . For o t he r a p p l i c a t i o n s where da ta o f t h e h i ghes t accuracy i s r e q u i r e d w i t h l i t t l e concern f o r t h e de lay between observa t ions and t h e de te rmina t ion o f t he r e q u i r e d i n fo rmat ion , a more t r a d i t i o n a l approach may be used. To meet a l l of these needs a v e r s a t i l e automated da ta r e t r i e v a l system i s demanded. The U. S. Naval 0bservator.y i s now implementinq such a system i n t h e area o f Ear th o r i e n t a t i o n i n f o rma t i on and f o r p rec i se t ime and t ime i n t e r v a l a p p l i c a t i o n s . Data are a v a i l a b l e through a s e r i e s of weekly, monthly, and annual r epo r t s , as w e l l as throuqh a d i a i t a l communications 1 ink , t o Time Serv ice machine-readable f i l e s .