>>>It makes me wonder if Dick Seaton and Martin Crane are out there
>>>somewhere in the UF-verse...
>>>
>>>...and I wonder if anyone will recognize the reference. :)
>>
>>Oh, I do. I wonder, though, which is bigger: Largo's AT&T or the
>>Skylark of Valeron...?
>
>Skylark of Valeron is just large enough to contain the 1000 km
>diameter circles of a Sixth Order projector.

That's the size of the core. There's Eris-only-knows how many km of armour wrapped around it, and the size changes depending on how much of a beating it's been taking recently.

My understanding is that it's supposed to be the size of a large moon, so it's probably somewhere around 2-5Mm in total.