|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
a question about milky way and constellations
Ahhh you need to check out Celestia at shatters.net/celestia . It will
let you go to any star in the sky and see ththe view from there. What you will want to do is set it to show the orbits of the planets, move around until you are looking at the solar system from the above (N) and then zoom out to the overview of the milky way. Then while in that view rotate the view so you see the galaxy edge on and then zoom in again. You will get a very good idea of the solar system's orientation to the plane of the galaxy as well as where things are in the galaxy. -- Remove My_Skin to E-mail me. wrothe: On Aug 8, 4:06 pm, Bill Hudson wrothe: ... For both Cassiopeia and Cygnus, you are looking pretty much along the galactic plane. ... But in what direction, from earth along that plane? Seems there would be a market for someone to writhe a 3D intheractive map of the galaxy, with stars and such in 3D, man that would be nice. Any software developers out there looking for a new product idea? |
#12
|
|||
|
|||
a question about milky way and constellations
On Wed, 08 Aug 2007 21:10:29 -0000, "
wrote: But all the stars of a constellation, or one could speak of the constellation itself, has to be "out there" in some linear direction away from earth, in some relationship to the galaxy center. That is what I am trying to reason out. Typical star charts do not speak of that, at least the cheap books I have. So it does help when you say Sagittarius is towards the center of out galaxy, from earth, that makes sense to me then when I see the constellation in the sky. Get a copy of Guy Ottewell's "Astronomical Companion" from http://www.universalworkshop.com/ It shows exactly what you are looking for, and much more. Bud -- The night is just the shadow of the Earth. |
#13
|
|||
|
|||
a question about milky way and constellations
William Hamblen wrote:
Get a copy of Guy Ottewell's "Astronomical Companion" from http://www.universalworkshop.com/ It shows exactly what you are looking for, and much more. Bud This looks like an interesting book (and quite reasonably price). I hadn't heard about it, thanks for posting the link. Esmail |
#14
|
|||
|
|||
a question about milky way and constellations
On Aug 8, 2:32 pm, " wrote:
snip i mean, when i see casseopia, or cygnus, *where* am i looking in terms of earth and the galaxy? Am i looking towards the center of the galaxy? away from the galaxy center but through our arm of the galaxy, etc.? Mellinger's Virtual Reality MilkyWay Galaxy will help you pair up those constellations with the band of the Milky Way's disk and the core of the Milky Way. http://canopus.physik.uni-potsdam.de/~axm/mwpan_vr.html Most planisphere wheels have the outline of the Milky Way printed on them. In addition to the many good recommendations listed above in this thread, I'd add Tirion's _Binocular Astronomy_. It has sections describing each arm of the Milky Way as it can be seen during each season. http://www.willbell.com/handbook/hand2.htm Another excellent out-of-print book that can sometimes be found in libraries is _The Guide to the Galaxy_ Cambridge University Press 1994 by Heather Couper and Nigel Henbest. This runs through objects that are visible in each galactic arm. Presently, we are entering August - the "Grand Display" month, in which the spinward disk of the Milky Way from the Galactic Core are seen _through_ the nearby stars in Sagittarius, Cygnus and ending at Perseus Double Cluster between Cass and Perseus. Taking the galactic core at the 0 deg point and tracing a 120 deg arc from Sag, to Aql, to Cyg (90 degs from Sag), thence to Cass and Perseus, you are looking at the spinward direction of arms of the Milky Way spiral galaxy. The problem interpreting this are a 3-D object is that everything is so distant you have no depth perception. A northern hemisphere view of the horizon looks something like this - http://members.csolutions.net/fisher...rbitAE_9PM.jpg - with the Milky Way's disk about 30-40 degrees above the eastern horizon at 9 pm. The anti-galactic center (180 degs from Sag) in the direction of the constellation Orion is under your feet, now behind the Earth. You are embedded inside and are surrounded by the Orion-Cygnus Arm. Most of the bright stars that you see are a halo of stars within 400 parsecs or 1,200 light-years of the Earth. Looking directly at Sag you are looking through the next arm in from our Orion-Cygnus Arm - the Sagittarius Arm and towards the galactic core. Along our 120 deg arc from Sag to Aql (at 20 to 30 degs from the core), you are also looking down the spinward direction of the Sagittarius-Carina Arm. The next arm in towards the galactic core in this same direction is the Scutum-Crux Arm. Almost no objects that are visible in amateur class telescopes can be seen in the Scutum-Crux Arm. The outer edge of the core of the Milky Way can be seen in M24, the Small Sagittarius Star Cloud. This is really just a hole in the clouds in the Sagittarius and Scutum Arms that are letting part of the bright galactic core peak through. http://www.seds.org/messier/m/m024.html http://www.library.gatech.edu/Barnar...1-pl027_sm.jpg From Aql through Cygnus (40 degs to 90 degs from the galactic core in Sag), you are looking down the spinward side of our Orion Cygnus Arm. The solar system's apparent direction of travel is at an oblique angle relative to the galactic disk. You are moving "up" of out the galactic plane towards a point in the constellation Hercules - that sits above the galactic plane. This is called the solar apex. http://members.csolutions.net/fisher...olarApexPM.jpg The true motion of the solar system (as opposed to its apparent motion) is somewhat different. The solar system moves in a wave pattern in a direction that is out of the galactic plane, but over time, gravity pulls it back in towards the galactic plane. Because the solar system is orbiting in a spinning disk, the true motion of the solar system is towards Aql, not Hercules. When you look towards Cygnus and down the spinward direction of the Orion Arm, your view is blocked by large gas clouds between 250 and 750 parsecs distant (about 750 and 2,000 light-years). Supernovae have evacuated cavities or "cells" inside these clouds. Deneb (alf Cyg) above the Great Cygnus Drift and Northern Coalsack is an example. Along the arc from the galactic core lies Cass and Perseus at about 120 to 130 degrees from the core. Here, you are looking at an oblique angle out the spinward side of the Perseus Arm. The Perseus Arm is the next galactic arm outside of the Cygnus-Orion Arm - away from the galactic center. The showcase Perseus Double cluster are open clusters that are exiting the "inside" of the gas wall of the Perseus Arm. http://www.seds.org/messier/xtra/ngc/n0869.html Since you are looking "out" of the galactic disk, note that the bright star clouds found in Cygnus, Scutum and Sagittarius are no longer seen. The "Milky Way" appears thinner and dimmer. There is less star formation going in the outer arms. When Orion swings around into view next fall, you will be looking through Orion and towards the inside edge of the outer Perseus Arm. Orion is located 180 degrees from the galactic core in Sag. Also note that the two great star forming clouds in our local part of the galaxy - M42 in Orion and M8 in Sagittarius are located about 180 degrees apart. M8, the Lagoon nebula is embedded in the "back" or "outside" of the next arm in - the Sagittarius-Carinia Arm. M42 - the Great Orion Nebula - is in a cloud between the Orion and Perseus Arms. http://www.seds.org/messier/m/m042.html http://www.seds.org/messier/m/m008.html Hope that helps. - Canopus56 |
#16
|
|||
|
|||
a question about milky way and constellations
On Aug 8, 3:12 pm, " wrote:
snip But in what direction, from earth along that plane? Seems there would be a market for someone to write a 3D interactive map of the galaxy, with stars and such in 3D, man that would be nice. In addition to the reference to the Powell's _Atlas of Universe_ website discussed above, such software does exist (subject to the uncertainty of position limitation mentioned by Greg). See the Hayden Planetarium's _Digital Universe_ freeware. http://haydenplanetarium.org/universe/ It's difficult to install and use java based application, but it gets the job done with a schematic type display. See also my humble amateur effort in VRML at: http://members.csolutions.net/fisher...efProject.html - Canopus56 |
#17
|
|||
|
|||
a question about milky way and constellations
On Aug 9, 4:26 pm, canopus56 wrote:
..... Thank you all for the great references, books, links, software mentions, I have some research cut out for me but at least I now have some specific resources to go for. Randall (Beowulf) |
#18
|
|||
|
|||
a question about milky way and constellations
On Wed, 8 Aug 2007 16:43:53 -0500, Davoud wrote
(in article ): : ok so as I look up at the constellations in the sky, specifically those that the milky way galaxy goes through, or really any constellations, i am asking myself what direction in space am i looking with respect to our milky way galaxy? i mean, when i see casseopia, or cygnus, *where* am i looking in terms of earth and the galaxy... Where is M13? http://www.thinkastronomy.com/M13/index.html is now a free download for Mac, Linux, and Windoze. It used to cost $19. Davoud I can second Davoud's suggestion of using "Where is M13?". It was designed specifically to answer these sorts of questions. But then I'm biased since I wrote it ;-) -- Bill Tschumy Think Astronomy -- Austin, TX http://www.thinkastronomy.com |
#19
|
|||
|
|||
a question about milky way and constellations
On Aug 8, 10:32 pm, "
wrote: ok so as I look up at the constellations in the sky, specifically those that the milky way galaxy goes through, or really any constellations, i am asking myself what direction in space am i looking with respect to our milky way galaxy? i mean, when i see casseopia, or cygnus, *where* am i looking in terms of earth and the galaxy? Am i looking towards the center of the galaxy? away from the galaxy center but through our arm of the galaxy, etc.? That seems like a valid question any curious star gazer should want to know, I know I do. Is there some star map of a sort that shows our galaxy, location of earth in it, and the direction relative to earth and the galaxy of the constellations? That would be interesting to see. Look for the book "Binocular Astronomy" by Crossin & Tirion at your local library or buy it. It has a chapter on exactly what you are looking for. |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
43 Zodiacal Constellations | [email protected] | Astronomy Misc | 1 | August 4th 05 11:31 AM |
Constellations | Phil Hawkins | Amateur Astronomy | 16 | February 3rd 05 06:32 PM |
Photographing Constellations (?) | Pre-Valerian | Amateur Astronomy | 2 | May 20th 04 01:21 AM |
Constellations | Orions Belt | Amateur Astronomy | 28 | April 6th 04 10:58 PM |
Software to ID Constellations | Richard | Amateur Astronomy | 14 | February 10th 04 08:09 PM |