Pencil – Page 209 – Astronomy Sketch of the Day

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

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.

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

Stellar spirit

Ghost of a dying star

In the western reaches of elongated Hydra, near the western border of Sextans you will find a ragged string of four stars ranging in magnitude from 6 to 8 aligned northeast to southwest located 1.7° south of 4th magnitude Iota Hydrae and 2.5° east of 5th magnitude Tau1 Hydrae (a fine, widely spaced double star). The third star from the west (and slightly out of line with the other three stars) is 7th magnitude HD 83535. This bluish-white star is superimposed on the edge of a ghostly planetary nebula known as Abell 33. My best view of this limpid pool of nebulosity was achieved with a 20mm Plössl (yielding a magnification of 45x) and an OIII filter. This setup revealed a small faint disk of tenuous nebulosity about 4½’ in diameter in contact with the 7th magnitude star on its southwest edge. The edges of the disk were reasonably sharp and the brightness faded gradually toward the darkened center. At other magnifications (both with and without the filter) the view was less distinct and the nebula became almost impossible to detect at magnifications above 60x. The 16th magnitude central star was not visible, but a trio of 13th magnitude stars (two of them a close pair) are perched on the northwestern edge of the nebula.

Abell 33 was discovered on Palomar Observatory Sky Survey plates by George O. Abell and published in the April 1966 Astrophysical Journal (Abell 1966). These nebulae, being very faint and of relatively large angular size are classified as ‘old’ or ‘evolved’ planetary nebulae. Observing the 86 objects in Abell’s catalogue constitutes one of the supreme observing challenges for amateur astronomers with large-aperture scopes; fortunately a few of them, including this one, are accessible in fairly modest equipment provided the observer has access to very dark skies and an OIII filter. Recent estimates place Abell 33 at a distance of about 1,100 light years from Earth (Phillips 2005), which implies an actual diameter of about 1.4 light years.

Subject: Abell 33 (PK 238+34.1)
Object Type: Planetary Nebula
Constellation: Hydra
Right Ascension (2000.0): 09h 39m 09.1s
Declination (2000.0): -02° 48′ 31″
Magnitude: 12.4n/15.7s
Diameter: 268″
Classification: 2b

Observer: Eric Graff
Location: Cuyamaca Mts., San Diego Co., California (4,000 ft. elevation)
Date & Time: 12 March 2007 at 04:30UT
Transparency: NELM 6.7, TLM ~14.1
Seeing: Pickering 5-6/10
Telescope: Parks Astrolight EQ6 (6″ f/6 Newtonian Reflector)
Eyepiece: 20mm Parks Gold Series Plössl (45x, 70′ TFoV)
Filter: Lumicon OIII Filter
Sketching Materials: #2 pencil, black ink, blending stump, 24# copy paper

References:
Abell, George O. 1966. Properties of Some Old Planetary Nebulae. Astrophysical Journal. 144:259-279.
Philips, J.P. 2005. The distances of highly evolved planetary nebulae. Monthly Notices of the Royal Astronomical Society. 357:2:619-625.

A rose by any other name

The Rossette nebula, NGC 2237-8, 46

Here is a challenging object. It was at the threshold of visibility for me and my gear. The nebulae was visible at a power of 12.5 (40mm EP) and at 19x (26mm EP). It vanished at any higher power!! The sketch was made with help of a lumicon UHC filter. But the most significant aid in detecting the ghostly glow was wobbling the scope left and right. The eye is more sensitive to moving ghosts than to steady
ones. As a result of the UHC filter, the fainter stars are lost. But I wanted to concentrate on the nebulae. The sketch was made in Photo-Paint, based on a raw pencil-sketch behind the scope. I hope you like the view.

Rony De Laet

Sketch data:

Date : March 9, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
EP : 26mm SP
Power : 19x
FOV: 2.7°
Filter : Lumicon UHC
Seeing : 3/5
Transp. : 2.5/5
Sketch Orientation : N down, W left.

A dark horse

The Horsehead nebula is among the most photographed denizens of the deep-sky. But it is rarely the subject of a visual observation, much less a sketch. I made this observation the night of January 20, 2006, almost ten years to the day after my first observation of this ellusive object. Formally designated Barnard 33 (B33), the Horsehead is a dark nebula seen in the foreground of the delicate emission nebula IC 434. The contrast between IC 434 and the Horsehead is quite subtle; like a whisper in the night. But as long as the sky darkness and transparency are good, a 6-inch aperture is up to the task of seeing the famous Horsehead. On this night, the view in my 18-inch Obsession was truly stunning. Even unfiltered, the inky black form of B33 was obvious at 109X (22-mm Nagler Type 4 w/ Paracorr). My sketch represents a combination of two views. The first was unfiltered to reveal as many field stars as possible. The second was with a Lumicon hydrogen-beta (H-beta) filter in place to record the full glory of the B33/IC 434 complex. The Horsehead cuts into IC 434 along the nebula’s eastern edge. It is distinctively darker than the surrounding sky, having a genuine inky blackness as if someone has carelessly left the tip of their quill too long against the sky. The back of the horse’s neck, head, brow, and snout are all discerned. Some 60 stars frame the view.

I used HB and 2B Staedtler Mars Lumograph graphite pencils to make the drawing on a sheet of white printer paper. Gentle rubbing with the tip of my right index finger lended softness to the background nebulosity.

Bill Ferris
Flagstaff, Arizona