Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
rocco13
Got Milk?
Reged: 07/29/06
Posts: 2642
Loc: Phoenix, Arizona
|
|
Just wondering...for an observer in M81/82 for example...would their view of the Milky Way and M31 appear similar to the view we have of their galaxies? (Same proximity, angle of separation, etc)
--------------------
Rocco
Zhumell Z12
Super C8 (1984 vintage)
Celestron 102 f/5
and a cheap pair of binoculars
|
astrokido
space wanderer
Reged: 06/09/08
Posts: 660
Loc: Phoenix, AZ
|
|
M81 is about 10 times further than the Andromeda Galaxy. From M81, the MW would be seen a few degrees apart from Andromeda. The MW and Andromeda would be some 25 arc-minutes wide. That's about the size of M101 seen in our sky.
--------------------
- Gill C. - Celestron Cometron CO-100, 10x25, 20x80, Binochair, Nikon D40
The Night Sky Atlas: www.nightskyatlas.com
|
azure1961p
professor emeritus
Reged: 01/17/09
Posts: 731
|
|
I think we'd look M81-ish. M82 is a special case altogether.
M31 would seem within close proximity. It's a nice question for thought.
Who could possibly dream up whats in our galaxy merely by the things going on with our planet alone. All lost in the grey misty light of our own "deepsky" look.
Ive got to believe someones pondered us the same way from there. I wonder how they like m82!
Pete
--------------------
|
Man in a Tub
Not Retired!, But a little cranky!!!
Reged: 10/28/08
Posts: 2020
Loc: San Francisco, CA
|
|
I played around with the Extragalactic Atlas of the Hayden Planetarium's Digital Universe a few hours ago. The Digital Universe Guide gives instructions for picking another object or galaxy as your center or point of interest. From M81, the Milky Way appears basically face on. I haven't tried M82 yet.
The Tully catalog galaxy images in the Extragalactic Atlas are scaled and oriented. You really have to increase the image sizes and/or decrease your FOV angle (the equivalent of using a telescope). I'm no expert at doing this. What I've done is distorted but interesting. As far as I can tell, those galactic fly-throughs you see on shows like The Universe also increase galaxy image sizes for visual effect.
Hayden Planetarium's Digital Universe
Best Regards,
P.S. From M82, the Milky Way is tilted back and not quite face on and M33 is edge on. Don't know if I did this correctly. Before this attempt, I've only picked M87 as the point of interest and put myself in orbit at various distances.
Edited by Man in a Tub (09/23/09 08:26 AM)
|
Lard Greystoke
sage
Reged: 07/27/08
Posts: 377
Loc: Ohio
|
|
An easy way to estimate how the Milky Way will look from outside is to check the target galaxy's position against either the North or South Galactic Pole. Galaxies near our galactic pole will show our galaxy as face-on; galaxies near (from our point of view) our own Milky Way will show us as edge-on. The classic edge-on NGC 4565 in Coma is near the NGP and will show us as almost perfectly face-on; likewise the oblique NGC 253 near the SGP. NGC 6946 in Cepheus is nearly face-on to us, but will see us as nearly edge-on.
--------------------
Lard Greystoke
10" Odyssey Compact
"With Tantor, the elephant, he made friends. How? Ask me not."
|
Man in a Tub
Not Retired!, But a little cranky!!!
Reged: 10/28/08
Posts: 2020
Loc: San Francisco, CA
|
|
That was right on and very helpful. I set up the Digital Universe so that I was at NGC 253. Interestingly from way out there, M31 is edge on — really, really edge on. So, when some bemoan the cosmic happenstance that we can't see M31 face on, know this: others, if they exist, are missing much more of M31...
Best regards,
--------------------
Todd
Brunton Eterna 15x51 ° Garrett Optical Signature Series 15x70
Nikon Action EX 12x50 ° Oberwerk 15x60 and 20x80 Standard
Orion Paragon Plus Mount and Paragon XHD Tripod
Garrett Optical Series 2000 Grip-Action Monopod
|
FirstSight
Post Laureate
Reged: 12/26/05
Posts: 3873
Loc: Raleigh, NC
|
|
M33 and M101 make good case studies for why a view of the Milky Way galaxy nearly face-on might not be nearly so good a view for visual observers as e.g. a view of between around 20% to 40% from edge-on. Unless perhaps, you had very dark skies + large aperture (18" or especially 20" and above). Face-on spiral galaxies present, outside their inner core, a fairly tenuous mesh of stars only 3000 to 4000 light years thick (i.e. it's not a continuous blanket of stars covering all the voids at that angle/density/depth), seen even for fairly "close" by M33 is a distance of over 3 million light-years. Compare and contrast how bright a firefly edge-on NGC 7331 is at 45 million lyrs or M104 at 25 million lyrs (much more by some estimates) - when the shallow angle creates a much deeper, more continuous wall of light.
--------------------
Chris M., aka "First Sight"
Orion XT12i Dob with Moonlite CR-2 focuser
WO Megrez 90 refractor on UniStar Light mount
Nikon 10x50 Binoculars
Edited by FirstSight (09/25/09 01:17 PM)
|
Man in a Tub
Not Retired!, But a little cranky!!!
Reged: 10/28/08
Posts: 2020
Loc: San Francisco, CA
|
|
I understand your point for visual observers. But one can "daydream" about what a face-on M31 might look like in the astrophotography of someone like Rob Gendler. But alas, not in my lifetime...
Only rarely do I see M33 in my binoculars here in San Francisco. Just a dim puff of smoke — sometimes more, sometimes less.
Best regards,
--------------------
Todd
Brunton Eterna 15x51 ° Garrett Optical Signature Series 15x70
Nikon Action EX 12x50 ° Oberwerk 15x60 and 20x80 Standard
Orion Paragon Plus Mount and Paragon XHD Tripod
Garrett Optical Series 2000 Grip-Action Monopod
|
|
3 registered and 3 anonymous users are browsing this forum.
Moderator: Olivier Biot
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 282
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
