[TerminallyTired (Jason)]

Heavens Above and Stellarium only has something like 200 or so of the brightest satellites.

I performed a search for objects passing near M42 from 21:00 on the 22nd through to 00:30 on the 23rd AEST and came up with a list of 6 objects that pass through Orion at something close to the right speed.

GPS BIIR-07 (PRN 18) - operational GPS satellite - NORAD ID: 26690
GPS BIIA-10 (PRN 32) - operational GPS satellite - NORAD ID: 20959
GPS BIIR-04 (PRN 20) - operational GOS satellite - NORAD ID: 26360
COSMOS 2458 (734) - operational Glonass satellite (Russian GPS) - NORAD ID: 36113
AMC-14 - Geostationary US TV Satellite - NORAD ID: 32708
STRV 1A - UK Military Payload, function unkown - NORAD ID: 23125

The last two in the list have the right trajectory through the constellation but arrive much later than 22:16, the time denoted by your camera.

Without more accurate information on your location and the time of the shots its difficult to confirm any of these. Can you confirm that your camera is set to AEST?

My search included 1000 or so satellites, in reality there is something like 30,000 objects 1 inch or larger, that are in orbit around the Earth and tracked by NORAD. You used to be able to get element sets on almost all of them. Unfortunately since 911 paranoia has swept through the US DoD and they no longer publish large element sets.

I guess they do have a point as it makes it too easy to identify an observation as unknown, track it to derive it's orbital characteristics and predict it's location. It used to be quite easy to find classified military payloads as a result (the brighter ones at least). Now there are so many unknowns its much more difficult to track any given one.

Given how close Orion is to the Clarke belt and the speed at which your satellite was moving I would say its most likely to be a largish Geostationary unit that is no longer functional and is drifting though the graveyard. Without more information on the location and time of your shots and comprehensive elsets, its pretty difficult to say exactly which one.

L8r

TT