Why can i see stars naked eye down to magnitude 4.72 (confirmed) but not the andromeda galaxy?

[realflow100]

Why can i see stars naked eye down to magnitude 4.72 almost 4.8 (confirmed with stellarium) but not the andromeda galaxy or orion nebula?
I can also see a very very faint band of the milkyway at the zenith with heavy use of averted vision over period of 20 minutes. its extremely vague and barely detectable. but there is a cloud-like band. and i confirmed it with a photo with my camera so it is really visible.

but andromeda galaxy is non-existent naked eye.
its very faint in 7x50 binoculars. just a tiny fuzzy looking dot. same in a telescope. just a fraction larger looking dot.
I also cant see the orion nebula at all either naked eye. theres just plain nothing there. I see like 3 very faint "pairs" of stars. and the middle second-brightest one should be the orion nebula. but i dont see anything. just stars

Even with my telescope at 20-40x magnification orion nebula is just a slight glow around some stars. and the only details ive been able to pick out are the dust pillar in the middle. and very briefly over period of 20 minutes of observing I detected the curvy "wings" in averted vision

Something fishy is going on. everywhere i read and everyone is telling me andromeda should be visible with at least averted vision based on what star magnitudes i can detect. but i can't see any hint of it even when i know i'm looking straight at where it should be. (I can just barely detect the 3 stars leading to andromeda. Mirach and such) very difficult. but can see the last 3rd faintest star with averted vision)

The sky doesnt look dark at all by the way. its clearly glowing a dull bluish color. with yellow gradients in various directions.
I'm wearing glasses and I should have 20/20 vision (I can see the stars unebelievably sharper with my glasses on compared to without them.) i have astigmatism which makes stars look like enlongated vertical blobs. and much fainter too than with my glasses.

[Graeme1858]

Although the Andromeda Galaxy has a magnitude of 3.5 or so, that is a measure of it's total output and the thing is huge! It's area is equal to about six full Moons. The light that comes from it is spread over that area. So most of the galaxy is invisible. You need a Bortle 4 sky at least to see the core but then you will never see the rest of it naked eye. Apparent Magnitude is not really a useful measure of brightness when applied to galaxies. Surface brightness is a more useful measure. I can't remember what the surface brightness of Andromeda is!

Regards

Graeme

[realflow100]

When I read a bortle website it says partial views of andromeda naked eye in bortle 8
and naked eye limit at magnitude 4.5 with "best efforts"

either I can see stars fainter than my bortle level. or something weird is going on with either my eyes or the light pollution??

After 20 minutes of standing outside next to a field with no excessive streetlighting i still dont see any fainter details than the first couple minutes i stepped outside

Aside from pleiades no other deep sky objects are visible. but i'm not sure if the milkyway counts when its "ridiculously faint averted vision only. with like 30 to almost 45 degrees of averted vision. and only near the zenith.

[sdbodin]

Listed galaxy magnitudes are always too optimistic. Andromeda is mag 3.44, a crock, surface brightness is listed as an average of 22.3/ sqr arc-sec since it is soo huge, the nuclear region is about 15.5/ sqr arc-sec. I doubt if you could see it in the city. Numbers are from a web search, so mileage can vary, but I have no easy time in my Bortle 3 skies, old eyes, I guess.

Steve

[KathyNS]

You aren't going to see M31 under a Bortle 8 sky.

It is easily naked eye under a Bortle 2 sky with excellent transparency. I have had a non-astronomer, just randomly looking up at the sky under those conditions, ask me what that fuzzy blob was. It was M31, of course. No special skill or experience was required: the thing was obvious.

I can easily see it under my Bortle 3 skies, and I can usually see it from my astronomy society's star party site, at Bortle 5-ish, because I know where to look and what to expect.

But, as the sky gets brighter, the contrast of faint objects against the background gets less. Under city or suburban skies, you just won't see it.

Now, if you want a real dark-sky challenge, try M33. I haven't yet found a dark enough sky to see it, though I am told it is naked-eye in excellent conditions. I can almost convince myself that I have seen it, but I can't quite be sure.

[pakarinen]

Published mags for extended objects are usually mags that are integrated over the apparent area of the object. So a fourth mag object might well be invisible to the naked eye if it's spread out over a large enough area. Then consider LP, etc., etc.

And if I'm recalling that incorrectly, I'll have another taco, thanks.

[GCoyote]

Similar experience to the OP, I've tried for a year or so to see M31 from my Bortle 7-8 suburban home. With no luck. Just checked Astrospheric and tonight is predicted to be cloudless with good seeing (low turbulence) but very poor transparency (humidity, dust, and smoke from the wild fires).

My July trip to rural Michigan netted only one night of decent weather but it helped put a lot of this in context. Bortle 3-4 according to a web search, average seeing, average transparency. I could almost see the effects of the smoke as a haze over the star field.

Since you are also on the East Coast, I suspect humidity and therefore transparency is a part of your problem.

[helicon]

I have seen M31 twice naked eye from home when conditions were just right, very clear November evening with some fog obscuring the city lights. Last time was 3 years ago. Otherwise, it cannot be seen but is obvious in 7x50 binos.

[Richard]

I cant see it with level 8 or 9 at my place , have only seen it once as a grey blob when we had a huge power cut so a large part of my area went dark and then only with 15x70 binos , none of my scopes worked even at lowest power as my 32mm eyepiece just gave too much mag , when I had my WO 80mm I could have perhaps but had a tree in the way , tree is no more

[sdbodin]

In my first post,

... surface brightness is listed as an average of 22.3/ sqr arc-sec since it is soo huge, the nuclear region is about 15.5/ sqr arc-sec.


Should be converted to magnitude/ sqr arc-MIN, since a human 20/20 can see about one minute of arc. If, my math is correct, an arc-min is an area 3600 time bigger than an arc-sec.

Then: 2.5*log 3600 = about 9 magnitudes

Yields 22-9= 13th mag for the outer part
and 15-9= 6th mag for the nuclear region

This is for direct vision, avert vision has even poorer resolution but better sensitivity so the apparent brightness will increase , but I have no data to calculate it.

Help, someone check my math!!
Steve

[realflow100]

YIKES magnitude 6 for the core?
Thats disappointing lol. no wonder its just a vague averted-vision-only dot even in my telescope.

[notFritzArgelander]

YIKES magnitude 6 for the core?
Thats disappointing lol. no wonder its just a vague averted-vision-only dot even in my telescope.

But that's pessimistic. Seeing the contrast between an extended object like M31 or M33 and the background sky is completely different from detecting a star. The physiology of the makes the two tasks completely different.

From my former home in VA (Bortle 4) M31 was pretty easy, M33 was tough, and if I couldn't see the Orion Nebula the night was maybe not worth the trouble.

You really need a darker sky for this. If you can barely make out the Milky Way, your sky is too bright for naked eye detection of these things. The sky must be darker than the object.