Astronomy Sketch of the Day – Page 293 – Drawings and sketches of an astronomical nature

Cold clouds

This large prominence was on the sun’s south west limb on March 27, ’07. Activity was otherwise low. Paradoxically, prominences are cooler than the surrounding atmosphere. They are columns of sun-stuff trapped and held up in the magnetic fields above the solar surface. The trapped plasma cools, recombines into hydrogen atoms and then emits visible light to show up as a prominence. The glowing gas twists and swirls in the sway of the magnetic fields and can change its appearance from minute to minute.

Observed from England at 10.30UT through a SolarMax60 H-alpha ‘scope at 50-80X, seeing moderately steady. The sketch was made large on A4 Canford black cartridge paper using white Derwent Studio and Derwent Watercolour pencils, the latter dry. I try to avoid erasers or blending stumps as they can sometimes take away the immediacy. If necessary, unwanted marks or brightness are reduced with lines of black Derwent Studio pencil. It is necessary to work fast and to finish a sketch within ten minutes, any longer and the scene can alter significantly. Details of this prominence were changing quickly but it was visible in more or less in the same overall form for over two days.

Les Cowley

Stop by and take a look around Les’s spendid daily website “Atmospheric Optics”. Click on the link in the blogroll.

Galactic swing dance

Object: Messier 51, The Whirlpool Galaxy
Classification: Galaxy
Position: RA 13h 29.9 min, DEC 47° 12′
Distance: ~23 million light years
Visual Brightness: 8m4
Apparent Dimension: 11′ x 7′
Constellation: Canes venatici
Observing Location: Erbendorf, Steinwald, Bavaria, Germany (800 meters
above sea level)
NELM: 6m2
Seeing: II / VI
Transparency: I-II / VI
Date: March 15, 2007
Instrument: Dobsonian 8″ f/6
Eyepiece: Reese 9mm Super Wide Angle
Magnification: 133x
Sketching Materials: black cardboard, white pastels, white ink, blending stump

A lot of work and patience went into the above drawing of M 51 to bring out as much detail and structure as possible: after one hour of dark adaption, another hour of pure observing and one more hour of sketching was invested, to get a glimpse of the subtle dark and light structures inside the diffuse nebulosity, which is generated by the object. At a first look, two blurry, bright smudges appear in the eyepiece, which can each be separated into a bright, almost stellar core surrounded by a diffuse, somewhat less brighter halo. It becomes apparent that the two objects are not located directly next to each other, but that there is a somewhat darker area in between, which is suddenly “cut off” by a brighter region in the east: the “bridge” of matter connecting the two galaxies! Inside M 51 A two slightly brighter regions start to appear, which bend away from the core and “dissolve” in the galactic disc: a hint of the spiral structure! Finally, two faint stars can be observed, which are apparently located East and West of the core, they are supposedly stars in the foreground. It may be noted here that the detail depicted in the drawing is the result of many hours of observation and patient use of averted vision, resulting in some sort of “sum picture”, which is surely not visible at a first glance. The beginner may be completely satisfied, if he can recognize the two discs and their cores – all the other details will appear with constant and regular observing.

Sebastian Lehner

To a southern exposure

Comet C/2006 P1 (McNaught)
10 January 2007 2255 UT
10×50 Binoculars
Cold Knob, WV USA
Altitude: ~3°
Conte’ Crayon on textured pastel paper

For me, getting a look at the famous Comet McNaught was not easy. I had tried and failed two days earlier at sunset when trees and houses blocked the view and it was rapidly sinking lower each evening–in a couple more days it would be gone for observers in the Northern Hemisphere.

Determined to see this comet before it disappeared, I trekked to the top of a nearby mountain to get a clear view of the western horizon and set up my binoculars. It had snowed 6 inches the night before, but now it was clear. Before the end of civil twilight, the comet popped into view. As the orange winter twilight progressed, McNaught took on the appearance of a burning ember just above the horizon.

The sketch is taken from a graphite pencil sketch I did in the field. The most notable features at 10x were the bifurcated tail extending about 30 arcminutes to the northeast and the very bright coma. The comet against the orange background of sunset was unforgettable. I have seen many images of McNaught in magazines and online that were taken on the evening of January 10th and they all show that orange winter sunset.

Of course, Comet McNaught went on south to become the brightest comet in 41 years, visible during daylight, and with a tail so long that it extended back to the northern hemisphere. But I saw it before it became famous.

Michael Rosolina

Cradle of the stars

The Orion Nebula (M42, NGC 1976) is one of the most well known and observed nebulae in the heavens. This magnificent collection of gas and dust visible as the “middle star” of the sword of Orion measures 30 light years across and lies approximately 1,500 light-years away. The Orion Nebula represents a stellar nursery in which stars are formed from the accretion of hydrogen gas and dust into protoplanetary disks (or proplyds) as imaged by the Hubble Space Telescope (HST).

I made wide-field observation of the Orion Nebula on February 14, 2007 using an 8-inch (20 cm) F/9 Klevtsov-Cassegrain reflector (a catadioptric design employing a sub-aperture meniscus correcting lens combined with a Mangin mirror-lens secondary). The observation was made under very transparent (6/6) and steady (5-7/10) conditions. The core of the nebula appeared brilliant in the field containing the famous Trapezium. Fainter extensions were noted to project from the core, including elongated ones to the north and south. The rendering was initially made using graphite (6H to HB) on Bristol Board paper (smooth), scanned into Photoshop and reversed.

Carlos E. Hernandez

Pacific places amidst “magnificent desolation”

Distinctive crater Stofler resides in the midst of the dense and chaotic crater field of the southern hemisphere of the Moon. One clear but very chilly evening in January 2007, the challenge of trying to capture the view was more than I could resist – this is my attempt. The sketch was carried out using white and black Conte’ pencils and chalk pastels on black ‘Canford’ paper. I began by marking out the main crater shapes using white Conte’ pencil, then I used a small chunk of white chalk pastel, broadside, to lay down the mare regions, blending this with a fingertip and a small cloth. More highlights were added (white Conte’ pencil), and a putty eraser used to define some of the features (and shadow extent) by negative drawing where I removed areas of pastel previously laid down. More detail was added with white Conte’ pencil as I went along, but there really was far too much to capture and I realized that I would have to quit while I was ahead and finish my outside drawing time before the view changed substantially. Once back inside I tidied up the sketch, removing the inevitable unwanted pastel smudges with a putty eraser, and re-defining some of the darkened inner crater edges with black Conte’ pencil, then using blending stumps (with touches of both white and black chalk pastel) to make final tiny adjustments. The sketch has been inverted and rotated in paint shop pro to give the standard orientation.

Sally Russell

Date: 25 January 2007

Time: 21.10-22.00 UT

Equipment: 105mm AstroPhysics APO/bino-viewer (mag x60)

Lunation: 7.3 days, 48.7% illumination

Sketch size: 6″ x 8″

The southern highlands of the Moon are almost completely dominated by craters in the 20 to 100 km size range, randomly scattered about the region. One way to determine relative ages of craters is to note which overlay or superpose over other craters or features, and the crater that obliterates or partially modifies another crater is usually younger. It is this principle that is the foundation of a stratigraphic approach to understanding lunar geological history. In the lunar highlands there is no shortage of overlapping or partially modified craters, and as Sally points out this region is about as densely chaotic as any on the Moon. A careful look at her beautiful sketch also reveals one of the great unsolved mysteries of the Moon. Many craters have smooth flat floors and the adjacent surface topography between these craters is also relatively smooth. The big question is: what is responsible for these smooth areas? Do the smooth floors and intercrater terrane reflect episodes of highland volcanism? Or perhaps these areas are covered with thick layers of ejecta that settled out across the surface as a result of this large scale stochastical gardening.

A star in the guise of a comet

Here is a sketch of NGC 2261, the Hubble’s variable nebula.

Some informations :

– Telescope : Dobson Lukehurst 495/2032, Pentax XW 7 mm (x290), no filter.
– Date : 30/10/06, 04:00 UT.
– Place : Nailly, Yonne, France.
– Sky : not transparent (lim. magnitude about 5,0) but with very good seeing.

A draft was made during the observation, then I made two sketches : one with the stars, the other with the nebula (on a white paper and with a lead pencil). Then, I scanned the two sketches and saved negative pictures. The picture with the nebula was colored in a light green. And finally, I added the two images. The sketch is not perfect : the east side of the nebula was more luminous than the west side – it is not obvious in the sketch. But the color of the nebula seems (to me) well shown.

Bruno Salque

Here’s a link to a archived post on Astronomy Picture of the Day that discusses some of the fascinating aspects of Hubble’s variable nebula.

The shepard philosopher

When I looked outside that Sunday evening there was not a cloud in the sky and the eight day moon was shining down on me from a very favourable angle. There were far too many desirable sketches available, and my eyes darted from Rupes Recta toward the south, to Eratosthens and the shadows and highlands spinning off it, and further north to Plato sitting on the darkness of the terminator. It was a difficult choice, but I settled on Plato just because it had slightly more interesting shadows and also some very bright highlights emerging from the darkness near its northern rim. A long thin pointed shadow poured from the base of Mons Pico toward the terminator and also from another high area to its right as I viewed it. These shadows lengthening in the hour it took to do this sketch. Just above Mons Pico as I viewed (south is up) a change in the lunar surface was apparent in the form of an Eiffel tower shaped greyness which swept up to and finished at Piazzi Smith. Mons Piton sits with Piazzi in area across from Montes Alpes which had several sun kissed high points. I observed the needle like Vallis Alpes cutting a sharp gash in the surface through rugged lunar land, lit slightly on its northern edge. Feathery shadows set of the shape of Plato and detached from its northern rim, very bright high areas warmed themselves as they became uncloaked from the blackness.

Deirdre Kelleghan
President
Irish Astronomical Society 1937 – 2007

Sketch details:

February 25th 2007
20:45UT – 21:45UT
53.2000ºN, 6.1000º W
200mm/F6/6.3mm Plossel/193X
8.19 days
Seeing 2
Trans Average
300gm Daler R paper/DR soft pastels/Black watercolour pencil/wooden toothpick
www.irishastrosoc.org

Plato and Sheep

Nestled on the plains between Mare Imbrium and Mare Frigoris lies the nearly lava filled crater Plato. This 100 km, dark pool of frozen lava has a darker tone than the lava that filled the Imbrium basin. Crater counts indicate that the lavas that filled Plato are actually younger than the Mare lavas of Imbrium. The history of emplacement goes something like this: the Imbrium basin was created first, followed by the impact that created Plato, and then the gradual fill in of basaltic lava that flooded Imbrium and much of the existing basin rings and superposed craters. This left untouched some of the isolated massifs that are now known as Plato’s Sheep, including the towering Montes Pico (2500 meters high), Piton (2000 meters high), and the Tenneriffe Mountains (2500 meters high). Finally came the slow lava inundation of Plato itself. Above Plato and rendered with wonderful precision is the Vallis Alpes, a large graben (extension) fault which probably formed as a result of the original impact that created Imbrium. Dee’s beautiful sketch clearly depicts the drama that awaits the observer when the telescope is turned to this region as the terminator passes through.

Galactic fetters

Markarian’s Chain of galaxies

Sketch was made on copy machine paper, A4 in size, with regular graphite pencil and blending stump. Conditions were good, transparency was excellent , limiting magnitude was 5.70 but seeing wasn’t that great. I used 8″ F6 dobson and 10.5mm Baader Hyperion Eyepiece. Magnification was 114x.

Vedran Vrhovac

70 million light years away, the sprawling Virgo Cluster is home to perhaps thousands of galaxies. In fact the Virgo cluster, despite it’s great distance, subtends an angle of about five full degrees in our sky, making it ten times larger than the angle the Moon subtends. Markarian’s Chain, beautifully rendered by Vedran, includes M84, M86 and M88 along with a host of smaller elliptical, spiral and irregular galaxies. Studies indicate that seven of the galaxies in the Chain actually move together at the same relative velocity.

Resplendent raptor

M16 Eagle nebula

This nebula was drawn with graphite pencils on
white paper and then inversed after scanning.
The main field stars (until about magnitude 11)
was printed with a charting software and the
fainter stars and nebula were added during the
observation. It took about an hour to lay all the
details on paper.

17.5-inch dobsonian, F/4.5, 74 &125x, OIII filter
used for the fainter parts; 15/august/2004,
22h00UT, good transparency (visual limit of 6.31
in UMi); from La Clapière in the french alps at
an elevation of 1650m.

Yann Pothier

Radiant spectacle

Today, March 2, 2007, the sunspot number is zero.

The sunspot number on October 28, 2003 was 238. An X-17 solar flare erupted that morning. Sunspot groups 484,486, and 488 were associated with Coronal Mass Ejections and auraural activity. The attached watercolor was based upon a white-light solar image captured with a 4″ refracting telescope, a white-light-solar filter, and a digital camera. The image of the sun with sunspots 484, 486, and 488 was processed in Photoshop and then printed. In a photocoping machine a transparancy was made. The transparancy was placed on an overhead projector and the projected image was traced and colored with watercolor pencils. Then, with a brush, water was added to the sunspots and to the remaining surface and background.

If the use of an “overhead projector” sounds like something from a school project, it was. Students at the A.R. Gould School in South Portland, Maine have used this process numerous times to document their observations.

… just a thought about tracing. In the late ’90s, I sent a cardboard-box camera obscura to Betty Edwards, the author of “Drawing on the Right Side of the Brain”. In her book she recommends that one should try to copy an image that is upside down; she suggests that that may allow the observer/drawer to see what is there and not what one expects to be there. In the camera obscura that I constructed, the image was projected upside down. In our conversations I asked her about the whether she thought tracing was drawing. She said that if two people were to trace the same thing that the finished drawings would be different, because drawing is about how we see things. (She also said that tracing allowed muscles to build muscle memory. I suppose that that is similar to practicing scales in music.)

John Stetson