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Binocular Icon 56 : a tenuous Valentine Rose. ;)

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#1 rodelaet

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Posted 15 February 2009 - 04:01 PM

A Valentine Rose.

Some observations require a decent preparation, while other observations come as a pleasant surprise. On a clear night, after I had observed the Belt of Orion with my 8x56 binoculars, I swept the view across the border into the Monoceros region. I wanted to check if the open cluster NGC 2244 was worth a view from my backyard with my binoculars. Last time that I had seen NGC 2244 was with my 100mm refractor. Back then, the eyepiece was equipped with an UHC filter. The Rosette Nebula, NGC 2237, was a faint and difficult target, which vanished when I removed the UHC filter. The sighting with my binoculars could only be inferior to the previous observation. NGC 2244 can be found on a straight line from Betelgeuze to Procyon. I started with Betelgeuze, slewed my view slowly eastward and ran into NGC 2244 within a few seconds. The cluster glowed like a beacon in the dark. As soon as I centred the open cluster in the eyepieces, it lost a bit of its sparkling grandeur. But when I moved the binoculars, NGC 2244 seemed highlighted again in my averted vision. The cause of this effect is the presence of the low surface brightness of the surrounding nebula: the Rosette Nebula! Now I’m not saying that my binoculars show a detailed object. But they do allow the detection of the presence of this faint nebula, even without any filters. The Rosette Nebula can be named together with the California Nebula, or with NGC 2024. These objects are all difficult to see, but with the right amount of patience, experience and persistence, they are within reach of a pair of binoculars.
The main showpiece is the rectangular shaped open cluster NGC 2244. It is a sparse cluster and counts only one medium star, two faint stars and five very faint stars. The brightest star, 12 Monocerotis, at the SE corner of the cluster is not even a cluster member but a foreground star. NGC 2244 would be a rather boring object if it was not accompanied by the Rosette Nebula, NGC 2237. It takes time and patience to reveal the Rosette in binoculars. A little trick that might help is to keep the field ‘in motion’. The human retina is more sensitive to moving objects. A slow wobble with the binoculars is sufficient to stimulate the sensitivity of our eyes. The northern region of the Rosette Nebula appears to be the brightest feature of the amorphous glow. The sky E of 12 Mon also shows a brightening. The sky next to the western border of the cluster seems a tad darker, as if there is a hole in the nebula. Keep in mind that these features do not appear immediately. It takes time and patience to reveal these subtle aspects of the Rosette complex.
The Rosette cluster is almost 5000 l-y away and is related to the Monoceros OB2 association. Like the Trapezium stars in the Orion nebula, the cluster members of NGC 2244 are born in the Rosette nebula. They are estimated to be very young: less than 1 million years. Long-exposure pictures show that these young giant stars have blown a hole in the Rosette complex. The Rosette Nebula is huge. It measures over 1° in the eyepieces. The Rosette Nebula measures 85 to 100 l-y across, which is 3 to 4 times larger than the Orion Nebula, which is 3 times closer to us. We can only imagine how magnificent the view of the Rosette Nebula would be if it was at the same distance as the Orion Nebula.
The accompanying sketch might not reveal the whole Rosette complex at first sight. I decided to draw the nebula not too bright. You may need to darken the room and to take your time and use averted vision to see the soft tenuous glow of NGC 2237 in the sketch. You can also use the slider at the right side of the windows, and slowly scroll this post. The movement will stimulate the eyes to see subtle brightness variations.



Site : Bekkevoort, Belgium ( 51° N )
Date : February 14, 2008
Time : around 21.30UT
Binoculars : Bresser Spezial-Jagd 8x56
FOV: 5.9°
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: 5.3
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 15 February 2009 - 06:12 PM

Rony,

Very delicate but I have seen this view from a dark site. Beautiful work! :cool: You know, I enjoy your narratives as much as these stunning sketches. :bow: :rainbow: :bow:

Frank :)

#3 Charles Laird

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Posted 17 February 2009 - 12:48 AM

Even with a darkened room I missed a lot. I did some experimenting and found a good way to view this extremely faint nebula sketch is to tear a hole in a piece of paper. View through the hole to block out the bright area of the screen around the sketch. Look at it for a bit. It goes from "I think I might be seeing it, to wow there it really is!"

Splendid work as usual Rony. That is a true representation of real visual astronomy: the struggle to see. Now,I have a question for you. How do you render extremely fine detail like this in your field sketch or final sketch before image processing? I am assuming you are using graphite. I have tried with a blending stump but so far I always seem to get things too dark.

#4 JayinUT

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Posted 17 February 2009 - 01:03 AM

Rony,

Just another award winning sketch. Your talent and skill is just amazing. Perhaps someday . . .

A comment on one thing I do besides the darken room. Because I view on my laptop (MacBook Pro) I can not only adjust the brightness of the screen, I sometimes tilt the laptop back and forth which seems to simulate different views.

Bottom line, great sketch as always.

#5 CarlosEH

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Posted 17 February 2009 - 10:41 AM

Rony,

A beautiful and accurate observation of NGC 2244 and the Rosette Nebula (NGC 2237). You have recorded the appearance of this elusive nebula very nicely. I look forward to reviewing it myself soon. Thank you for sharing it with us all.

Carlos

#6 rodelaet

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Posted 17 February 2009 - 04:47 PM

Frank, Charles, Jay and Carlos,

Thank you for the kind words on my impression.


Charles,

I included a little test bar. It should help you to calibrate your monitor. Only the left tile should appear dark. The other tiles look brighter. The calibration is important if you want to enjoy all the darker subtleties of sketches.

These sketches are made in two phases. First comes the field sketch. This is the blue print which is rendered under low light conditions. I use a Staedler fineliner 0.1 mm to draw the stars and a H graphite pencil for nebulosity . The paper is common copy paper. Each star gets a label. This number reflects my estimation of the brightness of the star. For nebulae I use roman numbers I to V (ranging from V for being bright with direct vision to I for being only visible with averted vision). This scale allows me remember how bright I perceived multiple features in the eyepiece.

Back indoor, I make a complete new sketch. But this time, I use no paper, but the computer to draw the sketch. I work with the computer mouse and a digital tablet with a pressure sensitive pen. The great advantage of these digital sketches is the ‘layered’ technique : The sketch is build up with multiple layers. You can see these layers as sheets of transparent paper. Each object is drawn on its own layer : stars, glare, spikes, nebulosity. While drawing on one layer, the other layers remain unaffected. I can draw or erase stars inside a nebula without damaging the nebula. Each layer has its own opacity. I can adjust the subtlety of an object by altering the opacity of its layer with a slider on the screen. See the example included in the following posts. Once the sketch is finished, I combine all the layers with the background, and post it as a jpeg file.

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#7 rodelaet

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Posted 17 February 2009 - 04:49 PM

Here is a close-up of the field sketch while in progress. Because of the mirror mount, these sketches appear mirrored. I flip the sketch afterwards, to get the orientation right. The pencil 'oval' near the middle of the sketch represents a darker zone.

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#8 rodelaet

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Posted 17 February 2009 - 04:51 PM

Here is an example of the changing opacity of the nebula layer of my sketch. I first render the nebula with 100% opacity. This way I have clear view of what I’m drawing. Then I lower the opacity of the layer to get the more lifelike appearance of my impression.
I hope it all makes sense.

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#9 Charles Laird

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Posted 17 February 2009 - 10:56 PM

It makes perfect sense, I do not do computer processing but am generally familiar with some of the concepts such as layering. I thought your field sketching might be along similar lines as you described.

I think visual sketching is an extremely valuable counterpoint to the glorious images produced by modern astrophotography. It conveys the true nature of visual amateur astronomy and as such is an extremely valuable teaching tool. In my opinion, if something is difficult to see with a particular human eye, set of optics, on a given night, then it must be rendered difficult to see in the final representation. That is the true record. It strikes me as a beginner, that rendering something that is difficult to see as easy to see on paper or screen is easy, but rendering it as difficult to see is really hard. My goal is to represent things as they are to me and in that, I have a long way to go. In my opinion, your sketches do three things. First, they raise the bar of excellence for those who would like to improve their sketching. Secondly, they provide an excellent teaching and training tool as to what visual astronomy is all about. Some beginners are disappointed at what they see because they have only seen photographs. Many who have young, sharp but untrained eyes miss what older, dimmer, but trained eyes see. The older eyes know what to look for and how to do it. Thirdly, they emphasize that visual astronomy is all about seeing what it there. Seeing all of what is there not simply what is next on the list. Your choice of modest equipment and wringing all there is out of it serves as a good counterpoint to aperture fever. A wonderful time in astronomy is to be had without a great expenditure of money. Your nebula sketches are particularly valuable for me, they encourage me to grow into seeing the unseeable and sketching the unsketchable.

As your sketch library grows I hope you will at least entertain the thought of publishing your sketches in some way shape or form. I believe it would be a service to amateur astronomy.

Charles

#10 frank5817

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Posted 17 February 2009 - 11:14 PM

Charles,

Very well said.

Frank :)

#11 rodelaet

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Posted 18 February 2009 - 05:56 AM

Charles,

Indeed, very well said.

Everyone should decide for himself how much money he wants to spend on astronomical equipment. But pleasure does not always grow with the higher budget. As you point out, the true pleasure comes with patient observing, regardless the used aperture. Personally I do care about portability and easy of set up. My scopes allow me be ready and observe within a couple of minutes. This means that during the working week, if I have an hour to spent under the stars, I’ll be there. If I had bought an Obsession (and isn’t it everyone’s dream?) instead, I would have much less ‘miles’ under the stars than today.

About the publishing of my sketches : they are available on my website (see my signature below) and on the Binocular forum over here. .

Wouldn’t it be great if a whole bunch of sketchers could unite their sketches in a book, something like : ‘The annual selection of astronomical sketches by Cloudy Nights.’

Maybe one day… ;)


And now back to earth : Charles, if I read correctly, you do sketch also? We would love to have your sketches shared over here. What do you think, Charles?






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