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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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It's been a bit since I've had the scope out to view M31, but I saw something I can't understand. First, apologies if this question has been posted before.
In a 26mm Meade 5000 eyepiece in the scope listed below, I could clearly see the galaxy core. The 'exterior' of the galaxy went from down-right to up-left (in my eyepiece) - but - the galaxy core was clearly in the down-right segment. In other words, M31 appeared lopsided relative to the core.
I went into my Ken Graun's "Messier's Object", and did some Google searches, but no photos/images compare to what I've seen.
Is it just my inexperience at work here?
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MJ "Morg" Staley
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M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3452
Loc: Cambridge, MA, USA
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Quote:
In other words, M31 appeared lopsided relative to the core.
That's correct. As viewed through the eyepiece, M31's core is *not* centered with respect to the extended disk -- not in the long dimension nor in the narrow dimension.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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Tony - thanx - my sanity is restored. M31 is one monstrous galaxy.
As I said, it's been a while since I turned the scope on that thing. I can't understand why I didn't notice this 'anomoly' before.
I guess it's true what they say - the more you look, the more you see!
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MJ "Morg" Staley
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M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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scopethis
professor emeritus
Reged: 05/30/08
Posts: 624
Loc: Kingman, Ks
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The galaxy (M31) has a slight twist or warp.
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Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1228
Loc: Estonia
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From what I recall, part of the lopsided appearance is caused by the galaxy fading out rather gently on one side, and coming to a rather more abrupt end on the other. At least that's how I've always seen it. I don't know if that's caused by a dust lane, or something else.
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5022
Loc: Mobile, Alabama, USA
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It's not your imagination, M-31 is somewhat irregular because of it's proximity to M-32, M-110 and M-33 too. A wide field photograph of the entire galaxy will readily show not only is the nucleus somewhat offset from the center, it will also show the disk is warped and there is a a finger of stars extending from M-110 towards M-31. What you were most likely seeing was the inner dust lane, which appears as a sharp drop off in brightness on the side of the galaxy closest to us whereas it fades gradually on the far side. From a dark site the dust lanes are apparent and they are much more visible on the near side than the far side of the galaxy. The two smaller galaxies M-32 and M-110 are going to eventually merge with M-31 just as the Magellanic Clouds are going to merge with the Milky Way.
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3452
Loc: Cambridge, MA, USA
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Quote:
It's not your imagination, M-31 is somewhat irregular because of it's proximity to M-32, M-110 and M-33 too.
Not just that. Spiral galaxies have spiral arms, which are always of different lengths, thicknesses, and kinkiness. That's quite obvious when you look at photos of face-on spirals. Some of them are approximately symmetric, but they're the exception, not the rule.
The asymmetry is harder to decipher -- but still apparent -- for galaxies viewed relatively close to edge-on like M31.
On top of that, the side that's tilted away from Earth is naturally more obscured by dust than the side that's tilted toward Earth.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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