jut for interests sake...how loud a bang do you reckon a Buk makes when launched ... a pretty massive one Id imagine that could be heard miles away . and on a clear still summer day how long afterwards do you reckon its pretty massive curving vapour trail ...ten to 15 mile long...would be visible to absolutely everyone for many miles around .
You imagine incorrectly then. It doesn't make any bang at all when launched (unless the rocket motors fail). A small medium range rocket of few hundred kg isn't as loud as you doubtless think it is (unless you are standing within a few hundred yards of the TEL). It's not going to be heard from more than a couple of miles away in the immediate vicinity of the launch site (motor noise at altitude is going to be refracted away from and greatly attenuated for potential ground observers). As it (initially) accelerates to and through the transonic regime, without direct visual identification by trained observers the sound can easily be mistaken for a military aircraft. The vast majority of the public (any public) don't have much of a clue what they are looking at in the sky; fail to consider basic geometries, apparent angular velocities, mis-estimating range and speed, before even considering the physics of what is and isn't possible (see the Icke forums for examples). The engagement profile rapidly takes it away from local observers (this is a surface to air weapon, not surface to surface), close to the vertical in order to maximise range, reach optimum target interception speed, minimise chance of interception itself. These factors work against it being readily observed.
Aside from that, it was predominately cloudy that afternoon in that area:
so once the rocket passed through the cloud base (METARs report cloud decks at 700, 1500, 3300, 10000 feet) it would be significantly harder to follow (though due to the time delay in the sound arriving at the observer most would be unable to locate the rocket prior to obscuration anyway); it's not like potential observers (other than those responsible) would be anticipating a launch and prepared to watch it. The rocket and subsequent plume would have been greatly obscured within about 5 seconds (or less) of the launch which means everyone a mile or more away would have had great difficulty spotting it once they were alerted by any sounds (it would be shrouded in cloud before they heard it). The launch site identified by several sources has the nearest (sparsely) populated village over a mile away.
A rocket plume was photographed in the vicinity of the launch site, at low level, after the event:
Note that the portion of sky in that photo is some 50-100 miles away out over Russia where the cloud cover was reported as broken with a base of around 4000 feet closer to the border, and clear much further along the line of sight (consistent with METARs and Meteosat 7 IODC) allowing for scattering.
(red arrow launch/crash area, blue ellipse distant clearer sky).
Relevant METARs:
METAR UKDE 171430Z 07006G13MPS 010V120 9999 BKN033 BKN100 27/16 Q1010 02210370 TEMPO VRB10G15MPS 2100 -TSRAGR SQ BKN007 BKN015CB=
METAR URRR 171430Z 06005MPS 9999 FEW040CB BKN100 32/10 Q1008 04CLRD70 NOSIG=
METAR URWI 171400Z 11009G14MPS CAVOK 37/02 Q1008 NOSIG RMK SC065=
METAR URWW 171430Z 06002MPS 020V120 CAVOK 35/01 Q1011 NOSIG RMK SC070=
e2a: I see the RT video itself (6m30s in) provides one truth - it clearly illustrates the extensive degree of cloud cover in the area at the time - the sky wasn't clear at all.