Wikipedia puts its diameter at 5-6 million lightyears.
In Celestia, its radius is 1.832e+05 ly, which would only be a diameter of 366,400 ly.
It seems that there's a little discrepancy here.

So which is wrong?
TranslightDefender wrote:I searched the Internet for largest known galaxy, and its IC 1101.
Wikipedia puts its diameter at 5-6 million lightyears.
In Celestia, its radius is 1.832e+05 ly, which would only be a diameter of 366,400 ly.
It seems that there's a little discrepancy here.
So which is wrong?
TranslightDefender wrote:I thought it might be something like that, that the distance isn't known very well.
It seems that the Google results say a diameter of 5-6 million lightyears frequently.
A blog, answers.com, and Wikipedia say that its diameter is ~5 million ly, yet at the same time say its 1 billion ly away, which is the distance Celestia has it at.
Joey P. wrote:The Celestian size is wrong. IC 1101 is 5.8 million light years.
Actually, sadly for a software that is made to be education and 100% accurate, Celestia gets most sizes (especially that of stars) wrong.
Joey P. wrote:I know about Mu Cep. Many Italian astronomy websites have relied on Celestia and have accepted the 3,900 solar radii figure. I even saw a Brazilian Portuguese YouTube video that made Mu Cephei that big, and VY Canis Majoris at 7,720 sr!
The largest possible star size (not including Quasi-stars) is 2,800 solar radii.
Quasi-stars are 35,000 solar radii.
Joey P. wrote:Also, the largest galaxy is now J1420-0545 at 25 million light years wide.