Minimum Aperture for IC 1101

[GrassLakeRon]

Hi all,

What would be the minimum aperture for viewing IC 1101? Wanting to see if its in reach of my 12". Thanks all.

Ron

[Howard B]

Hi Ron,

I think you have plenty of aperture, but seeing it depends on how dark and transparent your sky is. If you're having trouble seeing IC 1101, you probably need to observe from somewhere with better skies - good luck!

[Jimi Lowrey]

I want to think I have heard reports of people seeing IC 1101 with a 10” under dark skies.

[GrassLakeRon]

Thank you guys. I find this interesting that it does show up on the clear skies observing guides.

[Clear Skies]

I find this interesting that it does show up on the clear skies observing guides.

It's not included in the current edition but I will add it in V3.0; which I unfortunately can not complete until 2024 as my iMac passed away this week after 8 1/2 years of loyal service.

The galaxy ought to be a not-too-tough observation in a 12" scope under decent skies.

Cheers,


Victor

[GrassLakeRon]

It's not included in the current edition but I will add it in V3.0; which I unfortunately can not complete until 2024 as my iMac passed away this week after 8 1/2 years of loyal service.

The galaxy ought to be a not-too-tough observation in a 12" scope under decent skies.

Cheers,


Victor

Victor,

Please see my comment as a compliment. Your guides are exceptionally through. I just found it odd. I love what you do and THANK YOU for all you do.

Ron

[ScottH]

Hi all,

What would be the minimum aperture for viewing IC 1101? Wanting to see if its in reach of my 12". Thanks all.

Ron

Ron, about two weeks ago I managed to see it as a very faint but elongated diffuse glow in my 6-inch. It was easier than I had predicted and would be doable in a 5-inch from the Southern US.

Scott H.

[ScottH]

Thank you guys. I find this interesting that it does show up on the clear skies observing guides.

Well, I found it interesting that it wasn't on Ronald Stoyan's Interstellarum Deep Sky Atlas! So, after observing it in my 6-inch, I informed him of both my sighting and that I found it missing on his IDSA.

Scott H.

[Don Pensack]

This galaxy is the brightest member of the galaxy group AGC 2029
I found it decent, but not spectacular in the 12.5" at 203x as it culminates at an altitude of 60° at my latitude of 35°N.
It is small: 1.1' x 0.6' but fairly easy to see due to its V magnitude of 13.22 (NED) and class E to SO (varies by source).
It is believed to have a distance of 1.155 billion light years (some disagreement here of +/- 100 million light years).
And its calculated size is a diameter of 3.9 million light years! At the normal mag.25 isophote, about 500,000 ly.
If it were where M31 is, the Milky Way would be a close satellite, and maybe within the halo of IC1101!

This discusses some of the uncertainties in size and distance:
https://en.wikipedia.org/wiki/IC_1101

[Jimi Lowrey]

Here is a size comparison of IC 1101 to the Milky Way.

5120

[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 (https://simbad.cds.unistra.fr/simbad/sim-basic?Ident=Abell2029&submit=SIMBAD+search) (says Guide 9.1).
Amazing enough the DSS interface (https://archive.stsci.edu/cgi-bin/dss_form?target=IC1101&resolver=SIMBAD) looks up wrong coordinates for it (deep in the south), while it's at 15 10 56.100 +05 44 41.19 as SIMBAD (https://simbad.cds.unistra.fr/simbad/sim-basic?Ident=ic1101&submit=SIMBAD+search) knows.
Strange !?
Here is the correctly positioned DSS image (https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_red&r=15+10+56.10&d=%2B05+44+41.2&e=J2000&h=20&w=20&f=gif&c=none&fov=NONE&v3=).
And some interesting read (https://ui.adsabs.harvard.edu/abs/2017MNRAS.471.2321D/abstract).

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

In case you're interested: here's a 2010 CN thread (https://www.cloudynights.com/topic/256094-ic-1101-largest-galaxy-visible-to-us/?p=3248438) with several comments...