Size of nebulae, galaxies on actual naked eye sky?

[cosmicalstorm]

Lets postulate I go outside at night with magic eyes that can view the night sky like a combination of state of the art astronomical equipment.
What would the sky actually look like with regards to large astronomical structures, would I see a mesh network of galactic filaments in every direction?

How big would nearby nebulaes be to my eye, would they be the size of my palm if I hold it at arms length?

I realize that the Andromeda galaxy would be the size of a small coin and HUDF is a postage stamp. But that's all the information google ever gave me.

Does anyone know some general guide to this stuff?

Cheers

[fgalkin]

Uh....you CAN see other galaxies with the naked eye. Andromeda from the Northern hemisphere, and the Magellanic Clouds from the South.

They look like slightly fuzzy stars.

Have a very nice day.
-fgalkin

[Simon_Jester]

Easy.

Calculate the size of the feature (say, 10000 light years wide). Calculate the distance to the feature (say, ten million light years).

Divide the size by the distance to get the angular width of the object in radians. For comparison, the full moon is 0.009 radians wide- so something that appears to be 0.001 radians wide will be about 1/9 the apparent width of the full moon, and so on.

Of course, this assumes your eyes observe all light that heads your way so you can see these tiny remote features, as mentioned in the OP.

[Ziggy Stardust]

Easy.

Calculate the size of the feature (say, 10000 light years wide). Calculate the distance to the feature (say, ten million light years).

Divide the size by the distance to get the angular width of the object in radians. For comparison, the full moon is 0.009 radians wide- so something that appears to be 0.001 radians wide will be about 1/9 the apparent width of the full moon, and so on.

Of course, this assumes your eyes observe all light that heads your way so you can see these tiny remote features, as mentioned in the OP.

Are there not also a lot of distortion effects caused by the atmosphere? For example, objects closer to the horizon appear relatively larger than an object of the same size that is "higher" in the sky.

[Imperial528]

There is definite distortion but it should be uniform throughout the atmosphere (with the exception for local weather conditions and air density) and there's probably a method to account for it if you really need to be that accurate.

However the size of objects near the horizon has to do with the way your brain processes information. For example, the moon. It's apparent size is the same whether it is high in the sky or near the horizon, however when your brain sees that it is near the horizon it assumes that it is further away than it actually is, and when it adjusts for that the moon appears larger because the distance is still the same.