Beautiful but Clueless - Understanding the Pictures

[Paul73]

I'm sitting on a train having a browse through the latest astro images proffered for the delectation the SGL masses. It ha just occurred to me that I have no idea to what structures the different parts of the images relate.

I was admiring this thread at the time : http://stargazerslounge.com/topic/217692-leo-triplet/

My confusion whent along the folllowing lines. In the galaxies:

- Black bits = dust, lots and lots of dust?

- Pink Bits = HA regions (whatever that means)

- Orange bits = loads of stars?

- White bright bits = loads of different types of stars?

- Hazy bits in Arms = less dense regions of stars or mostly dust?

- Tidel wispy bits = more dust or stars cast off the main structure?

- Bright blue bits = ????

Can anyone recommend some reading to help me understand / really appreciate these images?

Paul

[Paul73]

I meant -

The Images are beautiful. I am clueless.

Thought that I would clarify before people started asking for pictures, which would inevitably disappoint.

Paul

[Helen]

How about having a trawl through apod images? http://apod.nasa.gov/apod/astropix.html Each one has an explanation of what the picture shows

Helen

[Paul73]

How about having a trawl through apod images? http://apod.nasa.gov/apod/astropix.html Each one has an explanation of what the picture shows

Helen

Thanks Helen

This is exactly the sort of thing that I was after. It might take me a while to find out what all of the parts are. But I will be an informing and most enjoyable read.

Paul

[Knight of Clear Skies]

This APOD of the Leo Triplet may help a little.

[Christopher Davenport]

So was thinking about this one.

I stand to be corrected but I'll have a go.

The stars you see in the surrounding view are much closer and in our milky way.

We look through them at the galaxy's, that is +- 2200 times the size of our galaxy away. They are about 22m light years away and the galaxy is about 100k light years across.

At this distance all light is from stars.

(Billions of them so that they seem milky)

All dark in the galaxy is obstruction of light by debris, objects to small to ignite under thier own gravity. These objects can be larger than planets.

The colour we see are due to the heat / age of the majority of the stars in the area of the galaxy we look at. (Dust may change the colour and act as a filter?)

The direction and speed the galaxy is moving in can also cause a shift in the colour spectrum.

Ha is a colour in the red part of the spectrum (similar to infa red) which is difficult for people to see with the naked eye.

Edit. Tidel bits are due to gravitational interaction between them and are stars en mass being pull out of the galaxy.

Anway I open the floor to those wiser than I

[Owmuchonomy]

If you can beg, borrow or steal a copy of the book 'Turn Left at Orion' this is an excellent comprehensive and easy read describing some of the science behind everyday astronomical sights. I still refer to mine to this day.

[Paul73]

So was thinking about this one.

I stand to be corrected but I'll have a go.

The stars you see in the surrounding view are much closer and in our milky way.

We look through them at the galaxy's, that is +- 2200 times the size of our galaxy away. They are about 22m light years away and the galaxy is about 100k light years across.......

I

Christopher

Great answer. Thank you for taking the time to write such a clear and detailed response. Really got me thinking.

Paul

[Paul73]

If you can beg, borrow or steal a copy of the book 'Turn Left at Orion' this is an excellent comprehensive and easy read describing some of the science behind everyday astronomical sights. I still refer to mine to this day.

Thanks Chris

I have to admit that I had thought that this much recommended book was purely about star hopping so haven't invested. I'll look out a copy.

Paul

[starman1969]

I try to look at APOD every day. If I miss any, I can always look through the archives. Each image is always well explained.

[dan_uk]

http://download.cnet.com/APOD-Wallpaper/3000-2336_4-10976816.html

I've been using this for the last couple of years on both my PC at work and home, it changes your wallpaper each day to the current APOD and you can right click the icon in the task tray for the explanation.

Note some days are videos which won't get displayed and occasionally an image will fail to display if you have it on the stretched option, I usually use a black background with the scaled option.

Daniel

[ollypenrice]

I think the orange bits towards the galactic centres are likely to be from old, evolved Population II stars. We see these colours towards the centre of our own galaxy, too.

The blue bits will be the younger Population I stars plus reflection nebulosity - again, I suppose.

Amazingly the tidal tail in the splendid Triplet image is a place of star formation. I do find this remarkable.

Olly