Minimum Aperture for IC 1101

[Don Pensack]

Recent estimates of the Milky Way's size extend the disc of the galaxy to about 150kly because of the identification of an outer arm not previously known, ignoring the halo, which may extend to 900kly, or just a hair smaller than M31's halo.
The mag.25 isophote on IC1011 varies by estimate from 400kly to 550kly in diameter.
I believe the size estimate of a radius of 1.95mly for IC1011 includes its halo. That would place it in the top five for known size, for sure,
but that calculates out to around 5x as wide as the Milky Way.
That's huge, but not quite the size discrepancy seen in your mock up.

The illustration underestimates the size of the Milky Way because it doesn't include the halo, and overestimates IC1101 because it does.
Estimates of the size of IC1101 are all over the place, but the size estimate at the mag.25 isophote is not as large as the figure shown.
The most recent estimates I can find for the radius of the halos are 450kly for the Milky Way and 1.95mly for IC1101.

That means IC1101 dwarfs the MW, but not by as much as the illustration indicates.

[petersurma]

Yes it's the BCG of Abell2029 (says Guide 9.1).
Amazing enough the DSS interface looks up wrong coordinates for it (deep in the south), while it's at 15 10 56.100 +05 44 41.19 as SIMBAD knows.
Strange !?
Here is the correctly positioned DSS image.
And some interesting read.

Interesting object definitely, inserted into my TBO list, for sure.

In case you're interested: here's a 2010 CN thread with several comments...