: Yeah, it always amazes me how freaking large the ships in Star Wars are.
: Stuff like the Death Star is one thing, but even their regular fleet are
: filled with massive ships. Imperial Star Destroyers are "only"
: 1600 meters long; at that size they dwarf basically every UNSC ship out
: there; they are nearly a full kilometer longer than Infinity .

Huh? The UNSC Infinity is 5,694 meters long, longer than three ISDs lined up nose-to-tail.

On the other hand, the ISDs are more numerous than either Covenant or UNSC capital ships, with 25,000 of them in service at the height of the Empire's power. ISDs also have firepower that is at least on par with Covenant or UNSC warships. A handful of ISDs are capable of carrying out a Base Delta Zero operation, which is known in Halo as "Glassing".

On the gripping hand, the Galactic Empire was a galaxy-spanning polity, with all the resources and production capability that implies.

: Really the only ship I think is actually outsized in Halo canon is the Long
: Night of Silence ; it's ridiculous to believe that a 20+ km vessel could
: actually hide at Reach for any length of time. There's no way they could
: camouflage how much heat that thing must've put out, at the minimum.

There were "army hiding canopies" that hid the presence of Covenant troops from orbiting satellites. Whatever the Covenant were using on Reach, it went far beyond the performance we've seen from their active camouflage.

I think that the Long Night of Solace and her fleet were loaded to the gills with Forerunner artefacts, which also explains where that teleportation technology comes from. The camouflage was probably Dazzler technology. The relics that created the dazzling effect initially hid the Long Night of Solace as it entered Reach's atmosphere, and then they were transferred to the teleportation spires to create the army hiding canopy. That's why LNoS only appeared after at least one of the spires was taken out.

The scheme with the dazzlers and the army hiding canopies is overkill against UNSC forces, but I always thought that the LNoS was meant to hide from other Covenant forces. I think that the whole fleet was assembled by one of the Hierarchs to steal artefacts out from under the noses of the other two.