where is Vader's command ship???

why at the begenning of ROTJ vader was loaded off a Imperial Star Destroyer rather than his own command ship? (in-story reason??)

i think i know the out-story reason: b/c the model of ISD was about 2.54 m represnting 1,600 m while for the SSD the model used inthe movie was also about ~2.50 m but represnting over 8 km. So i guess the hangerbay could in the SSD model was way to small to try to film it, while the ISD model had a reasonable-size hanger crafted against its belly, thus more suitable for close-up shots

Is the reason for this from in-story perspective, the fact that Vader's command ship was used to ship the Emperor from the Imperical City to Endor?? (iam talkting about the in-story reason that the Lucas and co. had back in 1983) iam sure EU has the many ships designed for emperor's personnel use

there is also the fact that Solo at one point in ROTJ says to Luke "there are a lot of command ships" which makes people belive that even back in 1983 in their mind there were many command ships but yet at the begenning of ROTJ Vader's command ship is missing??

 

He took his shuttle and docked with a Star Destroyer that was heading towards the Death Star. Admiral Piett probably had a few duties that he had to take care off first and he brought the Executor along later on.

 

The Executer might have been busy trying to hunt down the Rebels at the time and couldn't be spared, whereas a smaller ship could be.

 

It was in orbit around Uranis.

 

The Executor's every move would have been traced by the Rebel spies, because Vader is one of the Imperial's Leading...leaders. If you take it right into the biggest Death Star, it would have drawn attention that something big was happening. To all sides.

 

So that is why the Rebels dispatched valuable assets of their scarce fleet to Uranis...