There are many galaxies that are big enough to see with the naked eye from Earth, since as Andromeda. The problem is they’re too dim to really see well.
Well, I’d like to solve this problem, so later on today I’m going to build a faster-than-light rocket ship and zoom out of our galaxy. (I’ve got lots of stuff in my basement to make it out of.) As the galaxy is about 100,000 light years wide, I think I’ll go out to a distance of 100,000 light years further from the galactic center than that, and well away from any satellite galaxy, lone star, or dust cloud, in black, empty space. That should give me about as good a view of the Milky Way as it is possible to get.
What would it look like from that vantage point? Would it be dim and hard to see? Or would it be an unbelievably spectacular sight, liek thet galaxy at the end of “The Empire Strikes Back”?
Well, we actually live in the Milky Way, and for most people it’s too faint to see most of the time. My guess is that if you go outside then it would be even fainter. If you see it edge on, then it would be pretty much as we see it, a streak of light against the sky. And if you see it flat on, then it would be a faint disk.
I’m not sure how literal you’re being here. So, at the risk of making it apparent that I’ve misunderstood you, I wanted to point out that there really aren’t “many” galaxies visible with the naked eye from Earth (and I mean visible at all - not “well” or “at all”. Just visible period.)
As you mentioned, Andromeda (M31) is visible, but you’re still gonna need a pretty dark sky (and know where to look) in order to see it. And that’s basically it for the Northern Hemisphere in terms of naked eye galaxies - one. (Now, some might claim that the Triangulum Galaxy - M33 - can also be seen. And I would have one word for them - good luck).
In the Southern Hemisphere, there actually are a couple of (irregular) galaxies pretty easy to see without optical aids. They are the Large and SmallMagellanic Clouds (not discovered during, but brought to attention, as a result of Magellan’s circumnavigation journey).
So, no more than four, and really just three, galaxies visible to the naked eye.
OK, I have checked up on this and it appears that Andromeda actually does subtend a larger angle than the moon. However, due to some sort of optical illusion, doubtless to do with its brightness, the moon appears to be considerably bigger. In any case, Andromeda does not appear very big, and what I suggested (a telescope) would work perfectly well.
A telescope is usually not a very good choice at all for viewing Andromeda. Unless you have a very low magnification, wide-field scope, all you’ll see is a concentrated grayish blur and, maybe, at the edge of your field, also Andromeda’s two immediate companion galaxies. In addition without such a telescope, you will not see much detail in Andromeda, and if you do, it won’t be “majestic” since you’ll be looking at only a very small part of the galaxy. Its overall grandeur and splendor - the type of thing that my home page shows - is captured only by wide field scopes (or painstaking adding of multiple narrow field exposures).
By FAR, a pair of binoculars it what ‘amateur astronomers’ should use if they hope to appreciate the jewel known as Andromeda.
As I understand it, it takes perfect vision and near-perfect seeing (i,e, perfctly clear sky with no terrestral light sources) to see M33, but it supposedly can be done, I did make out Andromeda once when much younger and with far better eyesight, but wouldn’t be able to now.
Interestingly, an extremely bright supernova in M81 would be (barely) visible to the naked eye. This would be the farthest possible naked-eye object, by a factor of about five. I wouldn’t count on its ever being possible during anyone reading’s lifetime, though.
Speaking as a VERY amateur astronomer, I would agree with this. I’ve trained a telescope and binoculars on Andromeda and by far, the binoculars gave me the better view. That was after I found it (admittedly, I had an idea of where to look) with my naked eye.
Binoculars are underrated as an astronomy tool. They’re cheaper and easier to use than a telescope, and you can see a lot of cool stuff with them.
Assuming you saw it with the naked eye (or else how would compare it’s size to the moon), you only saw the bright galactic core. The entire galaxy does indeed span a field of view much larger than the moon. See here.
For the OP, I was somewhat amused/excited to see this, since I asked almost the exact same question last year. I believe the consensus was that the brightness level would be similar to looking at a distant galaxy though a large telescope. No comment about the shape.
I did see it through some pretty good binoculars (they enabled me to see the moons of Jupiter from the Los Angeles suburbs, for instance), and I saw it on a clear night, in the mountains, with minimal light pollution. It still looked no more than a faint gray blur (although I was pleased enough just to see that).
I take your point that one would need a pretty fancy telescope to get a good view, but even building a telescope like, say, the Keck on Mauna Kea, would still be a lot easier and cheaper - and more actually possible - than traveling outside the galaxy.
