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Old 24-06-2019, 09:14 AM
Vixen Optics, Japan

Shark6 is offline
Join Date: Feb 2018
Location: Florey ACT Australia
Posts: 34
Originally Posted by GUS.K View Post
After a club observing night last saturday and a conversation with a friend regarding the structure of the milkyway, I decided to find out about what features of our galaxy we are actually looking at. There were a few clear nights during the week so I decided to go out and see if I could trace out the different parts of our galaxy.
The structures of our galaxy are as follows-
-The centre of our galaxy resides in sagittarius, not far from M6, but is obscurred from view due to the dust clouds of the sagittarius-Carina spiral arm which is the next spiral arm in from our own.
-We can see part of the central bulge in sagittarius- especially in the large sagittarius star cloud(Baades window).
-We can also see part of the next spiral arm towards the hub, which is visible thanks to a window through the gas clouds in the sagittarius arm, which is known as messier 24.
-When we look along the milkyway from scutum to Carina, we are looking along the length of the sagittarius arm, the scutum starcloud being the part of the arm that winds its way towards the core( the direction of galactic rotation), and towards Carina, we are looking into the arm as it trails away from the core.
- When we look towards Cygnus we are looking into our spiral arm( not a full arm but a spur arm known as the orion spur.) as it wraps its way towards the hub.
-When we look out towards Canis major we are looking along our arm as it trails away from the center.
Looking towards Aquila, we are looking at the interarm space between the sagittarius arm and our own arm as they curve into the hub.
-Looking towards vela and Puppis we see the interarm space between the sagittarius arm and our own arm as they trail away from the hub..
-When facing Taurus-Auriga, we are looking through our arm towards the galactic anti centre(180 degrees from the hub). The milkyway between orion and perseus is broader here because we are closer to it.
-In Cassiopia, there is another window through which the next spiral arm out from ours can be viewed( the perseus arm). This is not visible from my latitude(34 degrees south), but could be seen from northern australia.
-The inner boundary of our arm is marked out by the stars of sagittarius, scorpio, ara, lupus, centaurus and crux. Most of this information is available on the net, and I have two books with a fair bit of information about the structure of the milky way-Binocular astronomy by Crossen and Tirrion and Exploring the southern sky by Laustsen,Madsen, west which has a fold out panoramic image of the milkyway which made it easy to see where the different structures were.
Thanks for reading.
Great post Ivan , I think most people gaze at the MilkyWay without any idea of where in it we are...
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