Jeremy Perez – Page 147 – Astronomy Sketch of the Day

Crisium’s Clean Sweep

Mare Crisium
By Richard Handy

The history of the Moon is written by impacts and volcanism. Nowhere is this more apparent than the lunar maria. Mare Crisium, unique among the nearside maria for being completely embayed by the lunar terrae, formed as a result of a 25 km impactor that struck the northeastern quadrant of the Moon some 3.9 to 3.85 Billion years ago. Imagination pales in comparison to the fury of this event. At first impact, all craters that had formed previously in the target area were swept clean of the surface as a deep basin from 10-25 km deep and 500 km in diameter formed. The very surface of the moon, rebounding from the shock of compression, acted like the surface of a pond that was stuck by a pebble, as large undulating seismic waves spread out from the center of the impact, across the basin floor, lifting huge blocks of lunar crust and faulting them in concentric rings at regular intervals. Shock melted material mixed with pulverized regolith called fluidized flow fronts, splayed out radially and nearly horizontal to the surface, creating strange braided landforms and teardrop formations as they tore through crater walls, burying what they did not destroy. A rain of secondary impacts followed, some taking long arching trajectories before impacting several minutes later, hundreds of kilometers away into the distant surrounding terrain. Although the entire basin was created in a few milliseconds, the lavas that cover Mare Crisium itself took hundreds of millions of years to emplace. Impacts that create basins also create deep fractures or faults in the bedrock beneath them. Working in concert with these natural conduits is a mantle that is closer to the surface due to uplift. As a result basaltic lavas found easy access to the surface following these fractures and the Crisium basin gradually became Mare Crisium. Over the course of the next billion years various lava flows erupted onto the mare, covering large portions that had previously been filled in. Nevertheless the mare’s surface is still quite deep in relation to the mean lunar surface, in areas close to 8 km deep according to recent Clementine data. At the western edge of Crisium lies the dramatic butterfly winged rays of Proclus, ejected predominantly lateral to the crater, in two wide 40 degree fans as well as a few subtle down range dustings, the most obvious ray almost bisecting the mare. This is a result of a low angle impact (less than 45 degrees to the surface). As it turns out, Crisium itself is elongated in the east-west direction, perhaps the result of just such a glancing strike.

Here are the sketch details:

Subject: Mare Crisium Rukl: 26, 27, 37, 38
Date: 2-2-07 Started- 6:20 UT End- 8:37 UT (2-3-07)
Seeing: Antoniadi III Weather: Clear
Telescope: 12″ Meade SCT f/10
Binoviewer: W.O. Bino-P with 1.6X Nosepiece.
Eyepieces: W.O. WA 20mm Plossls
Barlow: none
Magnification: 244X
Lunation: 15.1 days Phase: 348.4 deg Illumination: 99.9%
Colongitude: 97.5 deg Lib in Lat.: -1 deg 51 min Lib in Long.: +04 deg 03 min
Sketch medium: White and black Conte’ Crayons on black textured Strathmore paper.
Sketch size: 18″ x 24″.

Salt and Pepper in Cassiopeia

M52 (NGC 7654) Cassiopeia Open Cluster
By Kiminori Ikebe

Difficulty level 1
Date of observation: 2002/01/05 20:30
Transparency/seeing/sky darkness: 2/2/3
Instruments: 32cm Dobsonian with XL21 at 70x
Width of field: 0.9 degree
This cluster is situated west of Cassiopeia’s letter W. It is fairly bright. Although it is a mid-size cluster, stars are well concentrated and individual member stars are bright and beautiful. At 90x it is almost fully resolved. A 7.9-magnitude star in the west stands out. There are many bright stars in the northwest. In the east there is a small condensation from where lines of stars extend outward. Also, a line of stars running from the center to the southeast attracts an observer’s attention. There is a triangular-shaped clump in the southeast somewhat detached from the cluster. There are many faint stars sprinkled in the outlying areas.

Mr. Ikebe’s sketch gallery can be found here: Visual Observation of Deep Sky Objects

A Stellar Swarm in Pegasus

M15
By Barry Chase

Perhaps the most dense of the Milky Way’s globular clusters, M15 lies about 33,600 light years away and is about 175 light years in diameter. It has undergone a core collapse and half the mass of the cluster resides within a 10 light year radius of its center. It is not clear whether this dense concentration is due to the gravitational interactions of the clusters stars, or if it is due to the influence of a supermassive object–a black hole–at its core. M15 is also the first globular cluster in which a planetary nebula was found. (This planetary nebula, Pease 1, is a considered a challenging target for amateur astronomers with large telescopes, dark steady skies, and lots of patience.)

Source: SEDS

Ikeya-Zhang’s Ionic Wind Sock

C/2002 C1 (Ikeya-Zhang)
By Martin Mc Kenna

C/2002 C1 Ikeya – Zhang on March 20th 2002 at 20.48 LT as seen through the 10X50mm binoculars. The 6 day old waxing crescent moon was high in the SW which drowned out the fainter secrets of the comet however I could still see a tail 7 degrees long which had a ‘forked’ appearance due to the possible detection of the fainter straight blue ion tail at a slight angle from the main dust tail.

The dust and ion tails were superimposed on one another at the time. With binoculars or the naked eye the comet was a pearly white colour however with the light grasp of a telescope one could see the tell tale blue signature of the more subtle and dynamic ion/gas/plasma tail. On March 3rd astrophotographers imaged a rare disconnection event within the ion tail caused by changes in the solar wind. Comet tails are the ‘wind socks’ of the solar system and hence observations and CCD images are of great importance to professional astronomers within this field.

Eta Carinae from Haleakala

Eta Carinae Complex and NGC 3293
By Jeremy Perez

Move mouse over image to see labels. Click for larger image.

The observing highlight of an evening atop the summit of Haleakala in Maui was gazing through my binoculars at the rich starscape in the vicinity of Eta Carinae. I had not done any homework on the area beforehand, so I approached it with unexpecting eyes. The mottled depths of the surrounding Milky Way, the smattering of intensely bright foreground stars, the abundance of open clusters of all shapes, sizes and intensities, and the stunning patches of glowing nebulosity made the whole region a delicious feast for the eyes. One incredible open cluster to the northeast, nearly took my breath away, but I did not have time to even attempt a sketch of it. Instead, I chose to render the region bracketed by the Eta Carinae complex and a much more manageable cluster, NGC 3293.

Eta Carinae was a brilliant orange star that surrounded itself in a plush comfort of nebulosity. This misty region ended abruptly to the south and then emerged again to surround a trio of bright stars. The observation and sketch were done more hastily than I would have liked and I know there was more detail to be extracted from this bright nebula, but I took what I could get. The northwest side of the view was punctuated by the small, bright open cluster, NGC 3293. Four bright stars announced themselves within its glowing boundary of unresolved starlight.

This section of the sky is still beckoning me, and I know I will have to return to it again with more time to spare. Even if I only have binoculars again the next time, it will still offer more than I can possibly absorb.

The sketch was created on Strathmore sketch paper with 2H and HB pencils. Nebulosity was shaded with a blending stump loaded with graphite. Color was added to Eta Carina in Photoshop.

Object Information

Eta Carinae is one of the most massive stars in the universe and is likely greater than 100 solar masses. It is about 4 million times more luminous than the sun, but radiates 99% of this energy in the infrared. Due to its extreme mass, it is expected to go supernova within the next few hundred thousand years. In the meantime, as it rapidly sheds matter, it goes through sporadic, violent outbursts. The most recent outburst peaked in 1843 when Eta Carinae became a magnitude -1 star, second only to Sirius. This eruption generated a rapidly expanding plume of gas that now forms a fascinating dumbell shape.

November Mars in Subtle Salmon

Mars
By John Karlsson

This was a great night, clear and fairly calm for where I live here in Vernon BC Canada. I couldn’t pass up sketching this one. It was late and I had to get up for work at 6:30. I only wish I had better optics to give me some more contrast. I did however use my variable polarizing filter to bring down the contrast. It was glaringly bright.

John

Note: John used Crayola pencil crayons to create realistic color for this sketch. He blended the colors lightly to prevent streaks from showing as much as possible. John layed down a peach base first, and overlapped this with a layer of orange. He applied shading for the dark albedo features using a blending stump loaded with graphite from a 2H pencil.

Precious Moments of Totality

Solar Eclipse
By Serge Vieillard

If you were about to experience the brief but awesome spectacle of a solar eclipse, would you take the time to immerse yourself in a sketch of the event? If you have a passion for sketching astronomical objects and events, you may find yourself attempting what Serge Vieillard did. On March 29, 2006, Serge and 14 other club members journeyed to the Sahara Desert in Libya to view the eclipse. Racing across the dusty landscape in 4x4s to arrive at the site on time, they set up to the southeast of the volcano, Waw Enamous. As the eclipsed deepened, they found themselves entranced by an indescribable atmosphere: the sky darkened, Venus appeared, shadows began to shift, Bailley’s Beads began to sparkle, leading finally to totality. With that, the immense corona blossomed before them while solar prominences emerged and evolved as the moon passed before them.

Rather than photograph this awe inspiring event, Serge chose to harken back to an earlier era of astronomy and he sketched it instead. Because totality would only last 4 minutes, he had to be fast and deliberate in his sketching method, observing with a Kowa 77 mm TSN-2 for wide views of the corona, and a Meade ETX-90 at 100X for viewing the prominences. During those brief 4 minutes, Serge sketched the main contours of the corona, and sketched in the positions of the dancing prominences. Immediately after totality broke, he spent the next several minutes finishing the details of the sketch while it was still fresh in his mind.

Serge used colored pencils to add color to the sketch. However, since he was drawing on white paper and would be inverting it after scanning, he used a technique adapted from his previous color observations and sketches of M42, the Great Orion Nebula. By pre-testing, scanning, and inverting the color values of several pencils, he was able to determine what colors would produce the best color once the sketch was inverted after scanning. The results speak for themselves in this outstanding illustration.

The entry from Serge’s website is included below in the original French. (Google Language Tools may be helpful in translating if you do not read French.) More of Serge’s incredible sketches can be found at his website: ASTRONOMIE AMATEUR OBSERVATION VISUELLE CROQUIS ASTRO.

Eclipse totale du 26 mars 2006, dans le désert Libyen, au sud est du volcan waw Enamous. Une aventure exceptionnelle que nous avons vécue avec 14 copains(es) du club. Découverte d’un pays, du Sahara, d’un autre mode de vie. Course effrénée des 4×4 dans la poussière pour être présent sur le site au bon moment. Une ambiance indescriptible, assombrissement du ciel, apparition de Vénus, des ombres volantes partout, les premiers grains de Bailly, arrachage des filtres et ça y est ! Couronne solaire énorme, nombreuses protubérances dont la visibilité évoluera au fil du phénomène selon de déplacement de la lune. J’ai tenté ce croquis, évoquant à l’ère du numérique une astronomie d’une autre époque, ambiance 1900, à l’oculaire de la longue vue L80 pour la couronne et de l’ETX x100 pour les protubérances. Les 4 minutes sont passées comme un éclair. Je n’ai eu le temps que de marquer au mieux le contour des différents panaches. Tout de suite après la totalité, l’image encore en mémoire, j’ai apporté la texture particulière et les finitions pour ce résultat étrange…

A Spiral That’s Not a Galaxy

NGC 5189
By Eiji Kato

NGC 5189 is an unusual planetary nebula located an estimated 3000 light years away in star-rich region of the constellation Musca. It is sometimes referred to as the “Spiral Planetary” and gets its unusual shape from our edge-on perspective.

An in-depth discussion of this fascinating celestial object can be found in this article by Andrew James.

More of Eiji Kato’s deep sky and comet sketches can be found in his gallery.

Early Holmes in Charcoal and Graphite

Comet 17P/Holmes
By Erika Rix

The comet was created with charcoal loaded onto a thick blending stump. I added some fine touches with a number 2 pencil for accuracy on the brightest areas. The stars were done with a number 2, .5mm and .3mm mechanical pencils.

Observation made with an Orion ED80 on an LXD75 mount, 21-7mm Zhumell eyepeice with diagonal.

Jupiter’s Twilight Farewell

Jupiter
Gas Giant Planet
By Eric Graff

Parks Astrolight EQ6 • 6″ f/6 Newtonian Reflector
7.5mm Parks Gold Series Plössl + 2x Barlow • 240x, 13′ FoV
1 October 2007 • 02:30-03:00 UT

By the 1st of October, Jupiter is slipping quickly into the evening twilight, so I was pleased to make this final observation of Jupiter for the 2007 opposition. The four Galilean satellites are arrayed as follows (preceding to following): Europa (forming a close pair with a 10th magnitude field star), and Io on the west side of the planet; to the east, bright Ganymede forms another close pair with slightly fainter Callisto. Another faint field star lies just beyond these two, masquerading as yet another Jovian satellite.

The cloud belts of Jupiter displayed a pleasing amount of detail. The north equatorial belt is considerably darker than the south equatorial belt, which is split in two by a bright lane. Conversely, the south polar region was more prominent than its southern counterpart. The equatorial region itself was quite bright with subtle indications of the festoon activity which has lately characterized the region.