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Binocular Icon 55 : Treasures of Uru-anna.

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#1 rodelaet

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Posted 08 February 2009 - 03:49 PM

Some 5000 to 6000 years ago, one of the most ancient civilisations, Sumer, was based in southern Iraq. The Sumerians invented their own written language. Many Sumerian texts have been found on clay tablets. The Sumerians also practiced astronomy and gave names to the constellations.
The constellation of the Hunter, Orion, was known to the Sumerians as Uru-anna or The Light of Heaven. It has been suggested that Orion is named from Uru-anna.

Uru-anna or Orion is indeed a bright constellation. Most of its stars belong to the Orion OB1 association. Such is the case with the ‘Sword’ of Orion, a part of the sky which can be seen with the naked eye as a line of four fuzzy stars hanging under the Belt of Orion.

This region of the Orion OB1 association is filled with very bright stars. Many of these stars are very young giants or supergiants. The brightest star of the scene is Iota. Just a few minutes S of Iota is the double star Struve 747. Its components are only 36” apart, but clearly split at 7x. Struve 747 may look a little elongated in the sketch, due to the lower resolution of the rendering. It appears to me that Iota could be the lucida of a little poor open cluster, of which Struve 747 is also a member. The showpiece of the scene is M42, the Orion nebula. My 8x56 binoculars reveal two stars in the middle of M42 : Theta 1 and Theta 2. The latter is accompanied by two fainter stars to the E. The heart of the Orion Nebula is extremely bright. It can be seen with direct vision, also from an urban location. With patience and averted vision, a larger part of the nebula can be witnessed. Several faint stars can be discovered in the fading glow too. The western part of the nebula is the largest and the most obvious ‘wing’ of M42. Its northern border seems to be sharply cut away. As if a dark nebula separates M42 from the fainter M43 a few minutes to the N. M43 looks like a faint star embedded in a misty glow. The dark nebula also curves S as if it wants to separate the Theta stars as well. The southern ‘wing’ is a very diffuse feature. It is the thick and long filament know from the photos, that point towards Iota. With averted vision, this filament can be seen with 8x56 binoculars.
At 30’ N of M42, the faint glow of the reflection nebula NGC 1977 shows up around 42 and 45 Orionis. A total of 3 stars can be seen within the nebula.
The final object is the loose open cluster NGC 1981, N of NGC 1977. My 8x56 binoculars show a total of about 10 medium to faint cluster members.
The above mentioned objects are all members of the OB1 association, at a distance of about 1600 l-y.

A second observation of this region with the 15x70 binoculars will be posted later.



Site : Bekkevoort, Belgium ( 51° N )
Date : January 18, 2008
Time : around 20.30UT
Binoculars : Bresser Spezial-Jagd 8x56
FOV: 5.9°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 2/5
Transp. : 3/5
Sky brightness : 19.86 magnitudes per square arc second near zenith (SQM reading).
Nelm: 5.4
Sketch Orientation: N up, W right.
Digital sketch made with Corel Paint Shop Pro X2, based on a raw pencil sketch.

(Note: if the sketch does look too dark on your monitor, try to darken the room.)

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#2 frank5817

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Posted 08 February 2009 - 08:19 PM

Rony,

I am happy to see you made and posted this sketch before winter ended. Those suns and nebulae are stunning in this wide field binocular sketch. This one looks to be among the more challenging sketches you have done. Great sketch and write-up. :bow: :rainbow: :bow: :cool:

Frank :)

#3 JayinUT

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Posted 08 February 2009 - 09:37 PM

Rony,

I really appreciate the observations, detail and clarity of your sketch and the writing that goes with it. I look forward to part 2!

#4 CarlosEH

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Posted 08 February 2009 - 10:36 PM

Rony,

An outstanding observation of this impressive region of the Winter sky. You have captured this wide field view perfectly. I look forward to your 15x70 binocular view. Thank you for sharing it with us all.

Carlos

#5 Macro

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Posted 09 February 2009 - 09:29 AM

It is amazing how you presented that! (Not just in written form either... the sketch is phenomenal.)

#6 Vincent Becker

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Posted 09 February 2009 - 10:00 AM

I looked at this region for the first time last week with my brand new Kepler 10x50 binoculars (known in the US as the Orion Resolux). Your sketch is really excellent from what I've seen!

I had a look at the three stars of the belt also and noted a curious asterism, a kind of broad ellipse of regularly-spaced stars around the central star of the belt. It reminded me of a firework.

#7 rodelaet

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Posted 09 February 2009 - 04:26 PM

Frank, Jay, Carlos, Macro and Vincent,

Thanks for the compliments.

Vincent, the Belt is another great binocular target, which is sometimes called Cr 70. It too is a part of Orion OB1. On a clear night, my 8x56 binoculars show the weak presence of NGC 2024; the Ghost of Alnitak.

You can see an impression of it over here. I believe that the ring of stars you mentionned is also visible.

Clear skies,

#8 Mark9473

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Posted 11 February 2009 - 02:21 PM

You absolutely nailed this one, Rony! :waytogo:

#9 rodelaet

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Posted 12 February 2009 - 04:49 PM

Mark,

Thank you for the compliments! :)

#10 rodelaet

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Posted 12 February 2009 - 04:51 PM

Here is the second binocular observation of the Sword of Orion. This time, I used the 15x70 binoculars. This observation was made on a later date, and under a less transparent sky. The gain in magnification allows for a slightly better resolution of M42. The bigger aperture adds more depth to the object. Both wings are easier to define. Most of the features of the Orion Nebula are easier to see. M43 also shows a clearer appearance. The same is true for the dark channel between M42 and M43. The gain in limiting magnitude is not spectacular.
It may sound contradictory, but NGC 1977 does not appear more prominently. But that can be due to the lesser transparency of the sky.

Site : Bekkevoort, Belgium ( 51° N )
Date : January 31, 2008
Time : around 21.00UT
Binoculars : TS 15x70 Marine
FOV: 4.4°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 2/5
Transp. : 2.5/5
Sky brightness : 19.60 magnitudes per square arc second near zenith (SQM reading).
Nelm: 5.2
Sketch Orientation: N up, W right.
Digital sketch made with Corel Paint Shop Pro X2, based on a raw pencil sketch.

(Note: if the sketch does look too dark on your monitor, try to darken the room.)

Attached Files



#11 rodelaet

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Posted 12 February 2009 - 04:52 PM

Here is a side by side composition of the two observations.

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#12 markseibold

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Posted 12 February 2009 - 09:11 PM

Rony

Beautiful renderings and excellent historical information on your part. :bow: :bow: :bow: I especially like your comparison of the two images. It reminds me of the dark sky compared to light polluted locations that I rendered and posted here recently of M42. > M42 Pastel Rendered from Dark Sky vs Light Polluted

Yours is a very good similar display to show how different the nebula can appear depending on sky transparency; ie; dark sky vs light polluted skies.

Thanks for sharing this excellent post with us,

Mark

#13 rodelaet

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Posted 13 February 2009 - 05:15 PM

Mark,

Thank you for the kind words. :)

#14 Daniel

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Posted 13 February 2009 - 08:23 PM

Do you realize that if it were not for you telling people that these were drawings... they ... along with myself... would think they were actual photo's!!!!

You have fantastic skills!

#15 frank5817

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Posted 13 February 2009 - 11:06 PM

Rony,

You have made a great comparison using the same target with different binoculars under different sky conditions. I can’t say I like one better than the other but I can say you are really good at this. Your drawings really capture the view as it is and you always do a super job of telling us what you are doing to create these great drawings. Plese keep doing these excellent drawings many of us look forward to seeing your next work. :bow: :rainbow: :bow: :cool:

Frank :)

#16 rodelaet

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Posted 15 February 2009 - 04:29 PM

Daniel and Frank,

Your kind comments are very much appreciated. Thank you. :)

#17 cildarith

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Posted 15 February 2009 - 09:25 PM

Beautiful piece of work, Rony! :)

#18 Agnotio

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Posted 16 February 2009 - 01:12 PM

The first sketch looks almost exactly what the view of Orion's sword is through my 9x50 finderscope, although probably a few more stars are visible in your field because my light pollution is worse than 5.4 nelm. By the way, how are you estimating the nelm and sky brightness, just eyeballing them by the conditions?

Very informative sketches, thanks.

#19 rodelaet

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Posted 17 February 2009 - 05:29 PM

Eric and Agnotio,

Thank you for the compliments.


Agnotio, I use the SQM by Unihedron.

This device works very quick and accurate. The limiting magnitude is derived by a formula.

#20 rolandlinda3

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Posted 17 February 2009 - 10:41 PM

Beautiful sketch. In Uganda one night the center of the sky opened up and I saw this area. I have never seen it so pretty since there is no major city for 100s of miles to disrupt the seeing. Your sketch reminds me of the night.

Roland

#21 GlennLeDrew

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Posted 21 February 2009 - 07:08 PM

Rony,
Some background info on iota Orionis. It's most likely the more massive star (actually it's a spectroscopic binary) ejected from the Trapezium cluster during the same event that flung the less massive, single stars AE Aurigae (currently lighting up the nebula IC405) and mu Columbae. Iota Ori, because of its much higher mass, has drifted a very much smaller distance from its parent cluster.

This dynamical ejection resulted due to the very high density of stars in the former Trapezium. Imagine how this cluster would appear if iota Ori, AE Aur and mu Col were still within it!

#22 rodelaet

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Posted 23 February 2009 - 05:04 PM

Thanks Roland!


I look forward to your sketches from Uganda.

#23 rodelaet

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Posted 23 February 2009 - 05:07 PM

Glenn,

Thank you for sharing this interesting story. It does bring a different light on iota Orionis. :cool:






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