So, a direct comparative procedure (not speculative etymologizing) yields
*(j)astre,bU, probably also *(j)astre,bI, *(j)astro,bU and *(j)astrU. Why
*asUtre,bU and especially *asUstre,bU?
2. What makes you think <
*o:k^u-ptr-o- is a "majority view"? I'm
aware of the following:
2.1
The etymology which looks like the "majority view" is < *o:k^ro-/*a:k^ro-
'fast (?)' + *-mbH- (/-embH-) 'animals' names-forming suffix', while Latin
accipiter is etymologized as <*a:k^i-/*a:k^u-. At least my sources (Vasmer,
Trubachev et al.) state that it's more or less the point of view shared by
Brugmann, Meillet, Vaillant, Petersson, Berneker, Sobolevskij, Bru"kner,
Niedermann, Specht, Sl/awski, Vasmer, Shevelov, Sadnik,
Aitzetmu"ler.
Haas thinks the Slavic word is related to Greek
(<pre-Greek) Astrabakos 'a hero's nom. pr.' < *ok^rnbho- (supported in
Sadnik-Aitzetmu"ller's dictionary).
2.2 I don't know who has supported
Vey's etymology unreservedly, except Machek, though he offered a slightly
different solution: < *o:k^u-pet-ros, a (problematic) cognate of
accipiter.
2.3 There's a number of more exotic/marginal points of view,
among them:
2.3.1 Loewenthal: akin to Venetic Assoparis 'hawk's nestling'
< Illyr. *assos 'hawk' < PIE *attos, a possible cognate of OIrish a'ith
'sharp', Lett. a:trs.
2.3.2 Mayer: akin to Late Latin astur 'hawk' <
Messap. < PIE *astr, cf. Latin uultur 'kite'.
2.3.3 Jagic': *ostrU 'fast
(?)' + *re,bU 'speckled'.
2.3.4 Uhlenbeck, Fraenkel, Bulakhovskij:
*jast(I)-re,bU 'patrige-eater'.
2.3.5 Bubrikh: < *n:t-trmbH-
'duck-thrasher'.
2.3.6 Sadnik and Aitzetmu"ler: prefix *ja- + *stre,bU (the
latter not etymologized).