NGC 2736
Sketch by Eiji Kato
Discovered in 1835 by John Herschel, this unusually straight segment of the Vela Supernova Remnant shock wave is sometimes called the Pencil Nebula. It lies about 815 light years away and is moving at about 180 kilometers per second.
Source: Wikipedia
Petavius Crater
Sketch and Commentary by Carlos E. Hernandez
I made an observation of the crater Petavius and environs on July 31, 2007 (03:00-04:15 U.T.) using my 9-inch (23-cm) F/13.5 Maksutov-Cassegrain. Petavius (25.3*S, 60.4*E) measures 110 miles (177 km) in diameter containing a central mountain range, prominent rille (Rimae Petavius, (50 miles (80 km) in length) and ridges over it’s eastern and northern sections. Smaller rilles are also noted over it’s floor. Wrottesley (23.9*S, 56.8*E) is the crater noted along the western border of Petavius. The elongated crater to the east of Petavius is Palitzsch (28.0*S, 64.5*E) which measures ~25 miles (41 km) and appears half illuminated and half in shadow. Hase (29.4*S, 62.5*E) is a disintegrated crater that lies to the south of Petavius and measures ~52 miles (83 km). Several craters in shadow (with illuminated rims) appear towards the terminator.
The observation was made using graphite (4H to HB) then scanned into Photoshop and adjusted.
Links to Petavius;
http://www.lpi.usra.edu/resources/cla/info/f2/
http://en.wikipedia.org/wiki/Petavius_(crater)
http://www.lpod.org/?m=20060814
Hickson 61
Sketch and Commentary by Bill Ferris
Move mouse over sketch to see labels.
Hickson 61: Galaxy Cluster (Coma Berenices)
RA: 12h 12.3m / DEC: +29º 10′.8
Instrument: 18-inch Obsession
This quartet can be found in northwestern Coma Berenices. 4.3 magnitude Gamma (15) Comae Berenices shines as a naked eye landmark about 3 degrees to the east. My sketch presents a 199X view in the 18-inch Obsession. The brightest of the four galaxies is NGC 4169, also known as Hickson 61A. This 12.2 magnitude S0-type galaxy covers a 2′ by 1′ area and is aligned northwest to southeast. It is westernmost of the four, becomes gradually brighter towards the middle and displays a stellar core. The slender galaxy 2′ to the northeast is Hickson 61B. Hickson 61B is a 13.6 (B) magnitude spiral seen nearly edge-on. It covers a 5′ by 0′.7 area in my drawing, tapers in brightness towards the ends and is aligned northwest to southeast. Also known as NGC 4173, this galaxy’s ragged form shows no hint of stellaring at the core. The other edge-on spiral in the field is Hickson 61C, listed in Dreyer as NGC 4175. It’s a 14.2 (B) magnitude object covering a 1′.8 by 0′.4 area. NGC 4175 features a bright mid-section and has nearly the same position angle as its sibling to the northwest. Finally, NGC 4174 equals Hickson 61D. At 14.3 magnitude in the blue and 1′ by 0′.5 in size, this stellar metropolis is the smallest and faintest of the bunch. Aligned northeast to southwest, NGC 4174 features a faintly stellar core within a surrounding disk of even brightness.
M41
Sketch by Michael Vlasov
M41 is an open cluster containing about 100 stars, including several red giants with a chemical composition similar to our sun. The stars are distributed over a volume about 25 to 26 light years across, and the cluster is receding from us at 34 km/sec. at a distance of 2300 light years.
M41 was possibly recorded by Aristotle in 325 BCE. Hodierna was the first to catalog it before 1654, then it was rediscovered by John Flamsteed in 1702. It was found again by LeGentil in 1749, and finally by Charles Messier in 1765. Phew.
Saturn
Sketch by Serge Vieillard
While visiting the Sahara in Algeria, Serge Vieillard observed and sketched Saturn on a clear, stable night in January 2008.
Solar H-Alpha
Sketch and Commentary by Erika Rix
2008 04 06, 1240ST – 1330ST (1640UT – 1730UT)
Solar H-alpha
PCW Memorial Observatory, Zanesville, Ohio, USA, Lat: 40.01 / Long: -81.56
Erika Rix
Temp: 62.1 °F / 16.7 °C
Winds: 3.5 mph from the East
Humidity: 52%
Seeing: 5/6 with moments of 2/6
Transparency: 4/6
Alt: 51.3 Az: 143.3
Equipment:
Internally double stacked Maxscope 60mm, LXD75, 40mm ProOptic Plossl, 21-7mm Zhumell
Sketch Media:
H-alpha – Black Strathmore Artagain paper, white Conte’ and Prang pencils, white vinyl eraser.
Added –25 brightness, +15 contrast after scanning in color at 300 dpi. Tilting Sun program used for digital Sun insert.
Triesnecker and Rimae on the shores of the Central Bay
By Richard Handy
Sinus Medii or Central Bay, is aptly named for its relation to the geographic midpoint of the Moon (the point on the surface where the Earth would appear at the zenith at all times). On the northeastern shore of Sinus Medii lies the Copernican Period crater Triesnecker, the 26 km archetypical complex crater. Only hints of its distinguishing characteristics are apparent is my sketch because most of the crater’s inner walls are cloaked in shadow in this view, awaiting lunar sunrise to reveal their contours. The intense highlights off the scalloped western wall is the only evidence of considerable mass wasting that the crater has experienced. Hidden in this view is a floor whose entire western half is buried in wall debris. The deviation from circular (polygonal) form that Triesnecker displays is apparent all around the periphery of the crater. Terrace collapse has resulted in a reduction in floor depth and a annular ring of hills that are hidden from our view here. A mid morning Triesnecker sports a central peak and a small mare like area of what appears to be impact melt. The larger the crater the higher the peak, a product of the rebound energy of a surface that is impacted. Triesnecker sized craters lie at the lowest energy level necessary to produce central peaks, consequently the peak heights hover around 300 to 500 meters, large craters between 80 and 100 km have central peaks that average 2 km high. Immediately to the east, the complex rille network of Rimae Triesnecker dominates the right side of my sketch. Several things intrigue me in this area. Despite Triesnecker’s obvious superposition on top of these features, it seems amazing to me that these rilles survived being buried by its ejecta blanket. However this sketch is probably telling for what it does not reveal, filled in rilles which might be responsible the isolated rimae segments I’ve rendered here. The biggest mystery to me is why these rilles are located in this area of the Moon in the first place. Wilhelm suggested extensional forces. Perhaps Procellarum/Imbrium and Serenitatis/Tranquillitatis mascons are responsible for their appearance here, meaning these rilles are interpreted as grabens. A quick look to the northeast and we are amidst the obviously volcanic domain of the Hyginus crater and Rima. The surface elevation in this region has subsided and that may be due to extensional forces and subsequent outflows of mare lavas and terminal eruptive episodes
Here are the sketch details:
Subject: Triesnecker and Rimae Rukl: 33, 34
Date: 1-26-07 Started- 4:38 UT End- 5:55 UT
Seeing: Antoniadi III to IV Weather: Clear
Telescope: 12″ Meade SCT f/10
Binoviewer: W.O. Bino-P with 1.6X Nosepiece.
Eyepieces: W.O. WA 20mm Plossls
Barlow: 2X Televue Powermate
Magnification: 396X
Lunation: 7.03 days Phase: 86.8 deg Illumination: 52.8%
Colongitude: 359.7 deg Lib in Lat.: -4 deg 33 min Lib in Long.: +03 deg 35 min
Sketch medium: White and black Conte’ Crayons on black textured Strathmore paper.
Sketch size: 18″ x 24″.
Sombrero Galaxy (M-104), NGC 4594
Sketch and Commentary by Frank McCabe
Occasionally from my home observing site the humidity drops low enough to dramatically reduce the light scatter making it possible to observe bright galaxies. This night was one of those times.
Many of the bright galaxies of northern hemisphere springtime were visible this night and I selected the bright Sombrero galaxy in Virgo for sketching. This bright (9.0 visual magnitude), Sa spiral is just north of the Corvus border. Pierre Mechain discovered it in May of 1781 and 5 days later Charles Messier added it to his copy of the Messier catalog.
Vesto Slipher in the second decade of the 20th century measured the rotation rate and red shift of this magnificent spiral. This galaxy is receding at 1024 km/sec and is somewhere between 27.7 and 30.9 million light years distant. The nearly edge-on galaxy has a large glowing central bulge and a dark dust lane that can be detected with dark adapted vision in a 10 inch telescope. A spiral galaxy with large central bulge usually implies many globular clusters in association with that central bulge. This galaxy may have as many as 1200-2000 globulars in motions around the center. A research group led by John Kormendy in the mid 1990s discovered a super massive black hole at the core of this galaxy that measured one billion solar masses. This is a galaxy worth taking a look at on a clear night. You will find it at R.A. 12h 40 min. Dec. -11º 37min.
Sketching:
9”x12” white sketching paper; 4B graphite pencil and a blending stump made from a dowel rod; after sketching a 6” circle was cut from the sketching paper;
scanned and inverted; brightness of stars adjusted with MS Paint.
Scope: 10” f/5.7 Dobsonian: 26 mm widefield eyepiece 56x and 8 mm eyepiece 181x
Date and Time: 4-3-2008, 4:00-4:50 UT
Seeing: Pickering 7/10
Transparency: Excellent 4/5
NELM: 4.8
Frank McCabe
Oak Forest, Il. USA
Castor (Alpha Geminorum / Struve 1110)
Sketch and Commentary by Jeremy Perez
The fussy seeing provided a beautiful view of this brilliant double. The diffraction patterns shimmered and danced, adding a bit of challenge to viewing the pair, but also providing a mesmerizing, speckled light show. The primary of Castor appeared bright white while its companion hinted at a subtle blue.
Measuring this duo using the Dobsonian scope was very challenging. I was attempting the PA measurement without my external dial, and although it was very tough to get the primary to drift through the exact center of the eyepiece, the measurement worked out fairly well–differing from Workman’s calculated 2008.2 value by only .8 degrees. The separation estimate was worse though, since I couldn’t track and allow the stars to hover over the scale. (My estimate of 6.9 arc seconds was a bit over compared to the calculated value of 4.5 arc seconds).
| Subject | Alpha Geminorum (Castor / STF 1110) |
| Classification | Multiple Star |
| Position (J2000) | Gemini [RA: 07:34:35.7 / Dec: +31:53:16]* |
| Position Angle* | 59° [2008.2 my measurement] 58.2° [2008.2 Brian Workman’s DS Calculator] |
| Separation* | 6.9″ [2008.2 my measurement] 4.5″ [2008.2 Brian Workman’s DS Calculator] |
| Magnitudes* | 2.0 / 2.9 |
| Spectral Types* | A1V / A2Vm |
| Date/Time | MAR 19, 2008 – 10:45 PM MST (MAR 20, 2008 – 05:45 UT) |
| Observing Loc. | Phoenix, AZ |
| Instrument | Orion XT8 (203 mm dia./1200 mm F/L) |
| Eyepieces/Mag. | 10 mm Sirius Plössl + 2X Barlow (240X) 12 mm Meade Astrometric EP + 2X Barlow (200X) |
| Conditions | Mostly Clear, Gibbous Moon |
| Seeing | 3-4/10 Pickering |
| Transparency | NELM Mag ~4.0 |
| *References | The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996); Starry Night Pro Plus 5.8 |
73P-C/Schwassmann-Wachmann 3
73P-B/Schwassmann-Wachmann 3
Sketches by Kiminori Ikebe
Two years ago, comet 73P/Schwassmann-Wachmann put on a memorable show for observers. The two brightest components of the fragmented comet had reached 6th magnitude and were separated by about 9 degrees when Kiminori Ikebe sketched them on the night of April 30, 2006.
