Sagittarius - Your Amazing!!!

[ngcles]

Hi Suzy, Carl & All,

Yes Suzy, Sagittarius is a very special patch of sky and there's lots and lots to see. If you are patient and have a 10" 'scope, there are probably more than 100 objects to see. Even with a 6" there are probably 50-odd that are a worthwhile look -- 20-odd of these are globular clusters. M8 and M20 are magnificent too.

There is a very good chance the Globular Cluster M54 is an "import" into the Milky Way galaxy and has been "donated" by the Sagittarius Dwarf Elliptical. It was likely either a massive G.C of that system (it is comparable in mass and luminosity to Omega Centauri) or may even be the dense remnant core of that galaxy that is resisting dissruption because of its compactness. Terzan 7, 8 and Arp GC 2 may also have been donated to the Milky Way by the Sagittarius Dwarf Elliptical along the way

http://en.wikipedia.org/wiki/Sagitta...iptical_Galaxy

There are also several other G.Cs that are currently part of our Milky Way family but may well have been donated. Omega Centauri is one. NGC 2808, NGC 1851, NGC 2298 and M79 are others that might have been donated by the purported "Canis Major Dwarf Galaxy".

http://en.wikipedia.org/wiki/Canis_Major_Dwarf_Galaxy

The "Canis Major Dwarf" is still disputed. As it happens I have a friend at Sydney Observatory who is doing some work on resolving the question of whether it is a real dwarf or just an outer "bit" of the Milky Way.

There is also increasing evidence that the GC Terzan 5 isn't what it appears to be -- there is evidence it contains "dark-matter" for a start, three different bands of metallicity within its stars (like Omega Centauri) indicating it contains 3 different generations of stars and also has an very large number of millisecond pulsars (the highest number by a big margin). Its origin may also be "peculiar".

But as Carl said, our Sun and the solar-system are very much Milky Way born-and-bred for all the reasons he cited. As Carl wrote:

"These guys who come up with this nonsense don't understand even the basics of the science. The problem is, they read something about the subject they become interested in and then try to reconcile their own ideas with what they read. They take real science and twist it to suit their own agenda, which is usually to spread their particular ideas about how things are and what is going to happen. Just a quick and cursory look at their site will show you what they're on about and who they associate with. To say to take their site with a grain of salt would be adding insult to the grain of salt. Nothing of what they say has any basis in reality."

Spot-on Carl!

These folks are a bunch of very silly sausages -- pure and simple. They specialise in leaping to opinions that are without supporting evidence and contrary to well established science. Worse, they then proclaim it (loudly) as fact to the masses and denounce people who actually do have a grasp of the Science as being in a conspiracy with NASA and others to hide the truth from the world.

Frankly it is one of the big down-sides to the whole interweb-thingy.


Best,

Les D

[Suzy]

Thank you Les for all that wealth of information! It was really good reading!. Thankyou for taking all that time and trouble.

[renormalised (Carl)]

Originally Posted by Adelastro1

I agree with Renormalised's view. Our sun is a second generation star, ie. has gone through a supernova explosion and re-formed, which makes it a fairly old star (much greater than 5 billion years, which is the age of the erath). The higher atomic number elements above iron (Fe) were formed in that explosion (normal fusion reactions in stars can only produce elements up to Fe, but supernovae produce much higher pressures to fuse elements together to give heavier elements). The Sag stars appear to be younger stars if they are all of similar composition and no elements above about He. If they are of similar size to our sun then they must be younger as they haven't burnt all their Hydrogen/helium yet.

You're under a couple of misconceptions there. Yes, the Sun is a "2nd generation" star (probably more likely 20th generation, but I know what you mean), but it and the Earth are roughly the same age. We formed along with the Sun from the same cloud of gas and dust 4.657Ga ago. It formed a few million years quicker than we did, but close enough in time to be the same. The supernova you mentioned was probably the one (or one of a number of) that initiated the collapse of the cloud that eventually formed the Sun and the solar system. The Sun and the solar system most likely formed along with a couple of hundred other stars in an open cluster somewhere in the galaxy. Most of those stars have drifted apart from one another due to gravitational effects caused by other stars and the rest of the galaxy...which is the fate of all open clusters, to a greater or lesser extent (depending on where they are).

Most of the stars still left in and escaped from the Sagittarius Dwarf are all older than the Sun. They formed in gases that didn't have as much metal content as the gas we formed out of (due to its age and paucity of star formation). Because a star has less metals doesn't make it younger...some can be (depending on where they form), but less metals usually means a star is older. The gas it formed from hasn't been enriched by as many supernovae and outgassing from PN's over the length of time it was around for, before it formed those stars.

[renormalised (Carl)]

Originally Posted by Suzy

Carl & Wayne, thankyou so much for taking the time to explain that to me, I'm very grateful.

Gosh, I'm glad I popped this on my thread, otherwise I would have gone on to believe it. So confusing for Noobies you know, when you try to do the right thing and do some research and get wrong info like this. Thankfully, I am surrounded by intelligent people on here that can put me on the right track. If I may say, I am in constant awe of the amazing, intelligent, talented people on here. You lot included.

You're also surrounded by people who have degrees in the subject, and many years of experience as amateurs as well.

[astrospotter (Mark)]

I always enjoy a nice 2 degree or so wide APO refractor view of M24. You get a very busy field of a ga-zillion stars broken up with some objects.

There are two great examples of dark nebula in B92 and the less obvious B93 (not as impressive as coal sack but still nice). Then there is a small but wonderful open cluster in there by the name of Ngc6603 with a very fine line of stars almost as if to give this open cluster a 'major axis'. There are other objects there but the planitary Ngc6567 does not catch ones eye and neither does SH2-39. There is another more 'crude' open cluster that sort of stands out called Cr469 that is 1/3 the way from the big dark nebula of B92 towards the nice fine open cluster of 6603.

Just a fun diversion and M24 can even be picked out visually so easy to find just 7 degrees North-West of M22

[Suzy]

Originally Posted by astrospotter

I always enjoy a nice 2 degree or so wide APO refractor view of M24. You get a very busy field of a ga-zillion stars broken up with some objects.

There are two great examples of dark nebula in B92 and the less obvious B93 (not as impressive as coal sack but still nice). Then there is a small but wonderful open cluster in there by the name of Ngc6603 with a very fine line of stars almost as if to give this open cluster a 'major axis'. There are other objects there but the planitary Ngc6567 does not catch ones eye and neither does SH2-39. There is another more 'crude' open cluster that sort of stands out called Cr469 that is 1/3 the way from the big dark nebula of B92 towards the nice fine open cluster of 6603.

Just a fun diversion and M24 can even be picked out visually so easy to find just 7 degrees North-West of M22

Thankyou Mark! What you explained sounds fabulous. I will have a look - but the clouds need to buzz off first.

[Liz]

Originally Posted by Suzy

Thankyou Mark! What you explained sounds fabulous. I will have a look - but the clouds need to buzz off first.

Yes, Mark has often very good advice.

Our skies in Townsville are usually clear now for the next few months, come up for a visit Suzy ... at New Moon of course!!

[Suzy]

Thankyou Liz, and I am glad you are having clear skies at last. Now, if only we can!

Got all of my four books from Book Depostory - woohoooo! They came daily, across three days. It was like getting a pressie everyday . I do not know how they do this free shipping thing, really I don't .

I am loving my selection of books! My first book that I received, "The Atlas of the Messier Objects" (how big and heavy is this?!), fantastic book, unfortunately had 4 pages worth of information ripped out in half. So I emailed them and they emailed me back within 10mts telling me they were dispatching a replacement. What service! I thanked them profusely for there quick response and service.

My other books, are exactly to a "T" what I need. "Stars and Planets" and "The Messier Objects". They will help me to observe the detail. They look and smell beautiful and new, but very soon they are going to have a whole heap of wear and tear afflicted on them! And those going to be okay, because I want to use them lots and lots.

Thankyou to all that recommended these fantastic books. You have helped me majorly in my astronomical hobby. I am so happy I have got these books!!!

[Liz]

Originally Posted by Suzy

Thankyou Liz, and I am glad you are having clear skies at last. Now, if only we can!

Got all of my four books from Book Depostory - woohoooo! They came daily, across three days. It was like getting a pressie everyday . I do not know how they do this free shipping thing, really I don't .

I am loving my selection of books! My first book that I received, "The Atlas of the Messier Objects" (how big and heavy is this?!), fantastic book, unfortunately had 4 pages worth of information ripped out in half. So I emailed them and they emailed me back within 10mts telling me they were dispatching a replacement. What service! I thanked them profusely for there quick response and service.

My other books, are exactly to a "T" what I need. "Stars and Planets" and "The Messier Objects". They will help me to observe the detail. They look and smell beautiful and new, but very soon they are going to have a whole heap of wear and tear afflicted on them! And those going to be okay, because I want to use them lots and lots.

Thankyou to all that recommended these fantastic books. You have helped me majorly in my astronomical hobby. I am so happy I have got these books!!!

wow!! great to hear Suzy!! Book addiction can be as bad (or good) as EP addiction.

[astroron (Ron)]

Suzy, My Herschel 400 arrived today so with The Messier Atlas and Herschel 400, I have lots to keep me busy for a FEW years.
I have probably observed a big % of both catalogues, but now am going to do both with the 16" as a project