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Old 31-12-2010, 06:59 AM
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29/12/10 and 30/12/10 + sketch

Hi everyone,

On the 29th It was my birthday and what more could I wish for than a beautifull clear dark sky and my trusty scope.

As soon as the sun went down I started observing Jupiter and I was seeing a fair amount of detail with Io approaching the limb.

Then I started observing some old favorites like The Pleiades Which looked absolutely magnificent .These are really bright stars the cluster was riddled with smaller stars.I then went and saw Ngc 2516 the diamond cluster and was great just the way I remembered it form last year, very pretty open cluster.With the tarantula nebula being close I decided to give it a visit and it was awesome resembling almost the pictures,with huge tendrils of stars coming out of it.

I went back to jupiter and found that Io was now right on the limb and looking as if it was merging into the limb which was an awesome sight.I knew Uranus was close by so i gave it a quick glance.I could clearly tell it was Uranus as it had a pale green blue color to it, not as vivid as i remembered it from earlier this year though.Also right next to jupiter was the star 20 piscium which gave the fov some extra magnificence.

It was quite dark now an I decided to try and observed ngc 253.I found it and here are my notes on it.

NGC 253-This was quite a large galaxy covering almost half the fov of my 25mm ep.It had a very bright core with outreaching arms gradually getting fainter towards the ends.The galaxy had some thickness to it suggesting that it wasn't exactly edge on.The central region seemed to have some mottling and i popped in the 9mm to confirm this and I was surprised to be able to see a knot of to the side of the core.I think this may have been my very first sighting of a HII region in a distant galaxy.

After viewing the silver dollar I wanted to visit his neighbour ngc 55,and so I did.

Ngc55-This galaxy was almost as large as ngc 253 I could clearly see its irregularity with the core being off center.The core seemed elongated.it was quite a nice view.

That was all on the 29th.

Now on the 30th I dedicated myself to producing a sketch of M42(attached).

Thanks for reading my obs report and looking at my sketch
cheers Orestis
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Old 31-12-2010, 07:31 AM
jamespierce (James)
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Lovely sketch, I'm inspired to get out my pencils tonight rather than just hopping from object to object.
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Old 31-12-2010, 08:03 AM
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mental4astro (Alexander)
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Hi Orestis,

Your descriptive ability and observational skill is coming along very nicely. It is something that cannot be rushed. It takes time to gain these.

Your sketch too is top notch. A fantastic amount of detail. It shows what can be achieved with only modest gear, but with a keen eye at the eyepiece.

Mental.

Oh, and happy birthday, mate!

Last edited by mental4astro; 31-12-2010 at 10:50 AM.
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Old 31-12-2010, 10:59 AM
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Excelent sketch and a nice read. Well done on seeing detail in NGC 253 you must be stoked! It is infact one of the best telescopic galaxies in the entire sky and from a dark site it can be spectacular with dustlanes crisscrossing the core areas and many knots and bobs throughout. NGC 55 is not far behind.
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Old 31-12-2010, 12:53 PM
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kustard (Simon)
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Good to hear your reports as always Orestis.
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Old 31-12-2010, 10:49 PM
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HII region ?

Hi Orestis,

Wonderful report that was a pleasure to read. Excellent job in observing these two -- I looked at both last night too.

The enhancement you saw near the core of NGC 253 is almost certainly not an HII region. This eg is an exceptionally dusty one and in very large aperetures under true dark skys it looks finely mottled over quite a bit of the surface. There are a number of low surface-brightness spots (that are star-clouds) around the core that are contrasted with darker spots. Undoubtedly, this is what you have seen. The brightest one is not far outside the core to the southwest.

You are right -- it's not quite edge on.

Though it is somewhat surprising, in infra-red images it looks like a tipped over NGC 1365 -- NGC 253 is in fact a barred spiral when you look at it at this wavelength:

http://www.nasa.gov/mission_pages/WI...gc253anim.html

compare to NGC 1365 (superb image here by Mike Sidonio) and the similarity is striking.

http://www.pbase.com/strongmanmike20...85050/original.

Your best chances of seeing an HII region in another galaxy (outside the local group) is actually in NGC 55 that you also observed.

Okay, the core is off-set to the NW and you saw that, but apart from the core could you see any other spots along the major axis of the galaxy? There are two others not hard to see in 10" class 'scopes. Both are HII regions. NGC 55 is basically an LMC analogue (a barred irregular/small spiral) about 5 million ly distant seen edge on and is pretty lumpy -- like the LMC.

Well done!


Best,

Les D
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Old 01-01-2011, 06:20 AM
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Thanks everyone,

Les thanks so much for the description of the object.Awesome so I was seeing a dust lane.

I think I may have noticed some sort of bright regions in ngc 55.I might have to go revisit it.

So Is all the dust in ngc 253 obscuring its true identity as a barred spiral or is it it our line of sight therefore making it look foreshortened?

cheers Orestis
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Old 01-01-2011, 12:05 PM
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Paddy (Patrick)
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Great report as always Orestis. I liked in particular the inferences that your able to draw from you obs eg the orientation of 253 from seeing the dust lanes. And excellent sketch - well done.
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Old 01-01-2011, 01:32 PM
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Hi Orestis & All,

Quote:
Originally Posted by orestis View Post
So Is all the dust in ngc 253 obscuring its true identity as a barred spiral or is it it our line of sight therefore making it look foreshortened?

cheers Orestis
It's a bit of both, but the problem is somewhat more to do with dust than line of sight. Most of that dust is very fine particles of simple silicate compounds (like SO2) and carbon mainly in the form of fullerenes. Of course at near IR wavelengths, this warm dust is all-but transparent revealing the true galactic structure.

Cool huh ? (well I think so but I'm pretty nerdy!)



Best,

Les D
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Old 01-01-2011, 04:03 PM
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Imagine if it was face on .... what a sight that would be!
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Old 02-01-2011, 06:44 AM
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Quote:
Originally Posted by pgc hunter View Post
Imagine if it was face on .... what a sight that would be!
Now that would be awesome.

cheers orestis
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