Jeremy Perez – Page 148 – Astronomy Sketch of the Day

Capuanus at the Marsh of Epidemics

Capuanus at the Marsh of Epidemics
By Frank McCabe

At my geographic location during the fall, it is not uncommon to have a sequence of days with fog and mist under heavy cloud cover. At sunset the fog lifted and the sky cleared. It was time to take advantage of this break to observe and sketch.
The sketching target I chose near the terminator is Pre-Imbrian era crater Capuanus. This ancient crater rests on the shore of Palus Epidemiarum. At 58 kilometers in diameter, this is a large crater with extensive rim damage from multiple crater impacts. A narrow gap in the low north wall nearly connects the crater floor to the marsh. Brightly illuminated in the rising sun is the high western wall which towers at 2.5 kilometers above the crater floor. The basaltic lava on the floor of the crater appeared mostly dark. Two of the domes or dome-like rises could be detected on the southern crater floor. These volcanoes were active during the age of prokaryotic life here on earth 3.5 billion years ago. Ridges extending from the west of the crater, line up nicely with the margins of both mare Nubium and mare Humorum. Perhaps these are remains of a basin rim which was part of one of these seas.Across the floor of Palus Epidemiarum a wide segment of western Rima Hesiodus could be seen approaching the northern most of these ridge reminants. Two hours after I began sketching clouds moved in and closed my window on the moon.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, 9”x12”, white and black Conte’pastel pencils and a blending stump. Brightness was slightly decreased after scanning.

Telescope: 10 inch f/5.7 Dobsonian and 4mm eyepiece 362x
Date: 11-20-2007 0:05-1:40 UT
Temperature: 14°C (58°F)
fog, calm
Seeing: Antoniadi III
Co longitude: 33°
Lunation: 10 days
Illumination: 72.2 %

Frank McCabe

Colorful Witness to Tombaugh’s Discovery

Delta Geminorum

By Wade V. Corbei

This is an interesting double star (in all actuallity a Binary star) found in the constellation Gemini (as noted by the name). The Primary star is much larger than the companion star, and appears as a yellowish-white, while the companion appears as a nice contasting purple. Delta Geminorum also holds a historic significance as well, as in 1930 Clyde Tombaugh discovered the planet Pluto 1/2° east of this star.

A unique star with an equally interesting history.

Shadowplay on the Floor of Ancient Thebit

The Straight Wall, Birt, and Thebit on the floor of ‘Ancient Thebit’
By Richard Handy

What struck me immediately was the scimitar shaped shadow of the Straight Wall. I had observed the Wall on many past ocassions and I guess I had never seen it so close to the terminator. The long shadow cast by the fault (the “absolute best example of a lunar fault” according to Chuck Wood) amply displayed the fact that Ancient Thebit must have subsided on it’s western half into the Nubium basin. Ancient Thebit is the large circular partial rim flooded with mare lavas which dominates the center of the sketch. It is not to be confused by the snowman shaped 57 km Upper Imbrium crater Thebit, which lies within it along with Birt
and the Straight Wall. I’m not totally sure about my interpretation, but I believe that Rima Birt is demarcated by the shadow line just immediately above Birt, the small double crater on the left of the Straight Wall. The crater at the lower right is Purbach with its scattering of low peaks and small craters on an otherwise lava flooded floor.

Here are the sketch details:

Subject: Rupes Recta, Birt, Thebit on the floor of “Ancient Thebit”.
Date: 8-31-06 Start time- 3:40 UT Ending time- 4:27 UT
Lunation: 8.31 days Phase 88.1 deg Colongitude: 8.6 deg
Libration in Latitude: +6 deg 48 min Libration in Longitude: -6 deg 43 min
Telescope: 12″ Meade SCT f/10
Binoviewer: W.O. Bino-P with 1.6X Nosepiece
Eyepieces: 20mm W.O. Plossls
Magnification: 244X
Sketch medium: White and black Conte’ Crayon on black Strathmore Artagain paper.
Sketch size: 9″ x 12″

Arm of the Eastern Veil

Eastern Veil Nebula – NGC 6992 and NGC 6995
By Kiminori Ikebe

Lying some 1400 light years away in the constellation Cygnus is the beautiful supernova remnant known as the Veil Nebula or Cygnus Loop. When the supernova first lit up the sky thousands of years ago, it likely shone with the brilliance of a crescent moon (magnitude -8). The eastern portion of this broken circle of nebulosity is catalogued as NGC 6992 and NGC 6995. The full area of the Veil Nebula spans more than 3 degrees of the sky. In order to capture much of the eastern arm, Mr. Ikebe broke it down into the two sketches shown above.

(Source: APOD}

Mr. Ikebe’s notes about this nebula:

A magnificent view. The nebulosity in the shape of an arch in which bright and dark areas entwine in a complex manner. It is not possible to describe in words. It is difficult to draw it accurately and this sketch only shows how this nebula is perceived. The Veil Nebula is one of the most complex but clearest objects in the northern sky. The nebulosity from NGC 6992 to NGC 6995 is the brightest part of the Veil Nebula and even 10×42 binoculars reveal an arch-shaped nebulosity clearly.

(Re: NGC 6995) The complex area on the southern end of the arch in the east. The tip of the nebulosity divides into several branches looking like a human hand trying to grasp something. Off the tips of the fingers there are two faint areas, which may be IC 1340.

Equipment used: 32 cm Dobsonian at 70X
Sketch Media: Black paper, white paint (for stars), white watercolor pencil, and tissue paper. A Japanese language discussion of Mr. Ikebe’s sketching technique with photos can be found here: How to Make a Sketch. Translating the page using Google Language Tools can help with some of the text.

Archimedes in High Relief

Archimedes Crater
By Barry Chase

This drawing of Archimedes Crater is Barry Chase’s second Lunar sketch. The Lunar terminator’s close proximity provides strong, shadowed relief to the crater’s rim and surrounding terrain. Archimedes is 83 km in diameter, 2.1 km deep, and is the largest crater in Mare Imbrium. It does not possess a central peak, but does sport a 30 km long triangular promontory extending from its southeast rim.

Source: Wikipedia

Tuttle’s 2007 Debut

Comet 8P/Tuttle
By Martin McKenna

Comet 8P/Tuttle will be making a noteworthy apparition over the next couple months, passing .25 AU from Earth on January 2nd. Although it could become visible to the naked eye for observers with dark skies, it is still rather faint. Martin McKenna made an early visual observation and sketch of the comet on the evening of November 14/15. Note that since the comet is sketched at an appropriately faint level, any incidental glare on your monitor may make it difficult to see.

Notes from Martin’s observation:
Last night (Nov 14/15th 2007) I made my first visual observation of 8P/Tuttle at 03.58 UT in an incredible sky between banks of thick fog. Tuttle was located in the high northern circumpolar sky below Polaris and not far to the SW of 4th magnitude Delta Ursae Minoris. Using the 8.5″ F/7 reflector with 32mm 1.25″ eyepiece I conducted a systematic search through this area without success as on previous nights. However I managed to catch the comet which surprised me after 45 minutes of fruitless searching. The comet was extremely faint and looked like a circular patch of green haze in a field of faint stars. Tuttle was extremely diffuse – difficult to tell where the coma ended and the sky began. At centre I could see a faint pin prick condensation. No tail observed. It was observed faintly with direct vision however averted vision was needed to see its full extent. I was delighted to finally catch Tuttle at such a faint magnitude and look forward to watching its rapid development. 17P/ Holmes and 8P/Tuttle where a real treat at this silent hour of the night. This is my 42nd observed comet.

Mag: + 10.9 – 11.0, Dia: 3′, D.C: 2

Martin McKenna’s Comet Sketches

Messier’s Swan

M17 – The Swan Nebula
By Jeremy Perez

Observation Notes:
From Anderson Mesa, this nebula appears much larger than the typical swan shape that I see from home. The back of the swan is the brightest portion with the neck second brightest. The head appears to have a crest, and fainter wings appear above the body. The tail flows out to the southeast and then in multiple flowing arcs to the northeast and back around to the northwest.

I chose the 25 mm Plössl eyepiece to capture the full extent of nebulosity in its 66 arc minute true field of view. There was a bright yellow-orange star to the northwest of the nebula as shown in the image. This sketch took 2 hours to complete, but the sky was clear and the experience was enjoyable. My only concern was that it would sink too far into the murk in the southwest before I finished. 172 stars are plotted in the sketch.

I used 2H and HB graphite leads to plot the stars, and a blending stump loaded with graphite to shade in the nebula. After scanning and inverting the sketch I used a soft, mostly transparent brush to add a bit of glare around the brighter stars and added color to the yellow-orange star on the northwest side of the view.

Object Information*:
M17 is a region of star formation that shines by excited emission of light from radiant young stars within. The stars that heat and illuminate this nebula aren’t readily visible, but are hidden within. It is estimated that a small cluster of about 35 of these stars are imbedded in the nebulosity.

Photographically, the color of the Swan Nebula is reddish. This color comes from the hot hydrogen gas excited to shine by the hottest stars which have just formed within the nebula. However, the brightest region is actually a white color. This white color isn’t just a photographic overexposure as I had thought, but is apparently a result of a mixture of red emission light, together with reflections of the bright star light from the dust in that region. The nebula also contains a large amount of dark obscuring dust, which is responsible for giving it its distinctive shape. However, even this dark dust is glowing brightly in the infrared spectrum, heated by hidden young stars.

The bright portion of the nebula extends roughly 15 light years, but the total cloud seems to extend at least 40 light years. The amount of matter in the cloud is estimated at about 800 times that of the Sun, which makes it more massive than the fantastic Orion Nebula (M42). It’s estimated that M17 is 5,000 to 6,000 light years away. It was discovered by Philippe Loys de Chéseaux in 1745-46, but wasn’t widely known, and so rediscovered by Charles Messier in 1764. Under very favorable conditions, M17 is just visible to the naked eye.

This object is known by a number of common names: Swan, Checkmark, Horseshoe, Omega. It is also catalogued as: Cr 377, Lund 827, LBN 60, Sh2-45, h 2008, GC 4403, OCL 44.

*Source: SEDS; ngcic.org

The Water Bearer’s Spiral

NGC 7293 – The Helix Nebula
By Eiji Kato

The Helix Nebula lies roughly 450 light years away, making it one of the closest planetary nebulae (distance estimates range from 85 to 590 light years). With a diameter of 16′ for the main portion of the nebula and an outer halo diameter of 28′ its apparent size is among the largest known planetary nebulae. Although the nebula is intrinsically bright, its large size makes it a difficult target for visual observation under less than ideal sky conditions. It was discovered by Karl Ludwig Harding before 1824.

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

A Trio of Isolated Prominences

Solar Prominences
By Erika Rix

Seeing today was terrible and I tried my best to hang in there for a few good moments to see anything on the other half of the Sun. There was a small prominence, but I just wasn’t able to catch the fainter large one that others were able to see.

I did have some nice views by playing with the Etalon. There were some hairline filaments, or perhaps just darkened lines, scattered about on the disk. And three areas of proms on the eastern half of the Sun can be shown in the sketch.

Sketch done on black Strathmore Artagain paper with Conte’ and Prang white pencils. The graphic on the upper right is from Les’ Tilting Sun program. Some areas blended slightly with fingertip.

Early Details of a Golden Comet

17P/Holmes
Periodic Comet
By Eric Graff

Parks Astrolight EQ6 • 6″ f/6 Newtonian Reflector
7.5mm Parks Gold Series Plössl • 120x, 26′ Field of View
26 October 2007 • 09:45-10:15 UT

On the 23-24th of October, 2007 Comet 17P/Holmes experienced a major outburst, increasing its brightness 1 million times in just a few short hours, rising from 17th to 2nd magnitude. Such events are usually caused by the sudden release of gas and/or dust particles from the comet (the yellow color suggests the latter, in this case). During the early morning hours of October 26, the smoke from the Southern California fires had cleared sufficiently to make this observation. To the unaided eye, 17P rivaled the brightest “star” in the constellation Perseus – appearing only slightly less prominent than magnitude 1.8 Alpha (α) Persei (Mirfak). In 10×50 binoculars it had a bright yellow hue and looked slightly fuzzy or unfocused.

Through the eyepiece of my telescope the golden hue was striking as was its brilliance, near-perfect circular symmetry, and sharp stellar pseudo-nucleus. It resembled a huge, bright, yellow planetary nebula about 4′ in diameter. At high magnifications (120x, 240x) the central regions of the comet displayed considerable detail. A bright arc of material extends from the nucleus from south to west, with three prominent streamers involved in and extending from this arc. The circular coma has a somewhat annular appearance. Beyond the bright circular coma, two faint plumes of material, one to the northwest (elongated) and the other to the south-southeast (very broad and diffuse) could be detected by gently rocking the scope from side to side.

This comet was discovered by British astronomer Edwin Holmes on November 6, 1892 while conducting observations of the Andromeda Galaxy (M31). The entirety of its 6.88 year orbit is spent between the orbits of Mars and Jupiter.