I was just looking through the Fall of Reach.
Edit. Quote." Contact! Contact!" Lieutenant Domininque shouted." Enemy plasma torpedos away, sir!" Scarlet lighting erupted from the alien frigates-twin bolts of fire streaked through the darkness. They looked as if they could burn space itself. The torpedoes were on a direct course for the Iroquois." Course correction, sir?" Lieutenant Jaggers' voice broke with strain. His uniform was soaked with perspiration." Negative," Commander Keyes replied." Continue on this heading. Arm aft Archer missile pods. Rotate launch arcs one eight zero degrees." Aye, sir." Lieutenant Hikowa wrinkled her brow, and then she slowly nodded and silently mouthed,"...yes." Boiling red plasma filled half the forward view screen. It was beautiful to watch in an odd way-like a front-row seat at a forest fire. Keyes found himself strangely calm. This would either work or it would not. The odds were long, but he was confident that his actions were the only option to survive this encounter. Lieutenant Dominique turned." Collision with plasma in nineteen seconds, sir." Jagger turned from his station." Sir! This is suicide! Our armor can't withstand-" Keyes cut him off." Mister, man your station or I will have you removed from the bridge." Jagger looked pleadingly at Hikowa." We're going to die, Aki-" She refused to meet his gaze and turned back to her controls." You heard the Commander," she said quietly." Man your post." Jaggers sank into his seat." Collision with plasma in seven seconds," Lieutenant Hall said, She bit her lower lip. "Lieutenant Jaggers, transfer emergency thruster controls to my station." Yes... yes, sir." The emergency thrusters were tanks of trihydrid tetrazine and hydrogen peroxide. When they mixed, they did so with explosive force-literally blasting the Iroquois onto a new course. The ship had six such tanks strategically placed on harden points on the hull. Commander Keyes consulted the countdown timer on his data pad." Lieutenant Hikowa: fire the nuke." Shiva away, sir! On course-one eight zero, maximum burn." Plasma filled the forescreen; the center of the red mass turned blue. Green and yellows radiated outward, the light frequencies blue-shifting in spectra." Distance three hundred thousand kilometers," Lieutenant Dominique said." Collision in two seconds." Unquote. Those are two plasma torpedos fired by a pair of Covenant Firgates giving cover to a Carrier and Destroyer during the first battle near Sigma Octanus IV.
Edit: to any one that saw that before the Edit, sorry. But I didn't think I gave enough info when I did this last night, I was just tired.
So my last range on Covenant plasma was to close to the ISDs if we go with this, the Star Destroyers would never have got a shot off at that range. But this last part at the end would mean that they would be traveling near the speed of light, last I checked Covenant ships are faster then UNSC ships, so that would mean that they move faster than light with what are suppose to be sub-light drives. So how long do Covenant plasma torpedos take to accelerate to these speeds? They must take some time or the author made one giant typo at the end of there of what I quoted. So should we go with this data?
If this is right standard Imperial weapons just got thrown out the window at this range.
This has been a UNSC transmission.