Category: Nebulae

Milky Way Sights

Lagoon Nebula and Vicinity

Lagoon Nebula and Vicinity
Sketch and Details by Carlos Hernandez

My South Florida weather cleared temporarily on July 30, 2008 (04:00 U.T.) and allowed me to tour the Milky Way with my Oberwerk 11 x 56 binoculars. Many targets were visible but the Lagoon Nebula (M8) and Trifid Nebula (M20), as well as M21 and M28 caught my eye. The Lagoon Nebula (M8, NGC 6523) was visible as an elongated nebulosity which included clumps of stars (NGC 6530). The Trifid Nebula (M20, NGC 6514). The open cluster M21 was visible north of the Trifid Nebula and M28 towards the east (left).

A digital rendering made using Photoshop CS3.

Carlos

Riches of the Star Queen

M16

M16 – The Eagle Nebula
Sketch and Details by Eric Graff

Object Name: Messier 16
Also Known As: NGC 6611, Cr 375, Mel 198, C1816-120, IC 4703, Sh2-49, Eagle Nebula, Star Queen Nebula
Object Type: Open Cluster + Emission Nebula + Dark Nebula
Constellation: Serpens (Cauda)
Right Ascension (2000.0): 18h 18m 45.0s
Declination (2000.0): –13° 47′ 54"
Magnitude: 6.0
Size: Cluster 21′; Nebula 35′ x 28′
NGC Description: Cl, at least 100 st L & S
Discovery: Philippe Loys de Chéseaux, 1746

Date/Time: 4 July 2008 • 04:20 to 06:45 UT
Location: Oakzanita Springs (4,010 ft. elevation), San Diego Co., California, USA
Telescope: Parks Astrolight EQ6 • 6" f/6 Newtonian Reflector
Eyepiece/Magnification: Parks 15mm Gold Series Plössl • 60x • 52′ FoV
Filters: Lumicon OIII
Conditions: Clear, calm, 62°F
Seeing: Pickering 4-5
Transparency: NELM 6.3; TLM 14.0

The Eagle Nebula (or the Star Queen Nebula, if you prefer) is one of the most spectacular "Great Nebulae" in the sky – in photographs, anyway. Unlike other emission nebulae on Messier’s list (M8, M17, M20, and M42-43), the Star Queen does not willingly yield her secrets to the visual observer. In fact, she puts up a rather tenacious fight.

The sky was not quite wholly dark when I centered my scope on M16 soaring above the brink of Oakzanita Peak. The nebulosity itself was not visible yet, but I immediately set to work sketching the visible members of the bright and easy open cluster invested in the nebula. By the time this task was completed the sky had darkened completely as the billowing clouds and star-studded reaches of the Milky Way cast their net above the entire eastern horizon. In the eyepiece gossamer veils of tenuous nebulosity draped lazily over the sparkling star cluster like a lumpy, disheveled cloak.

The best view in my scope occurs at 60x magnification with an OIII filter. The nebulosity is complex and the hazy morass dances with subtle possibilities, but getting that detail onto paper was challenging; the region around the famous "Pillars of Creation" was particularly difficult in this regard. Once I was satisfied that I had done all I could with the central portion of the nebula I was able to pick up faint, nearly featureless extensions on nearly every side by placing the cluster just outside the field of view and sweeping slowly from side to side (N-S or E-W; kind of like looking for the tail of a comet).

Omega Blossom

M17

M17
Sketch by Serge Vieillard

Serge Vieillard worked on this detailed drawing of M17 over two nights while visiting Spain in 2007. He used a 46 cm Obsession telescope, a variety of magnifications and an OIII filter to prepare the drawing. He was not satisfied with the proportions of the first night’s sketch and so made use of an accurate, pre-plotted star field to concentrate on observing and redrawing the nebula on the second night.

Dark Nebula Nexus

M20

M20 – The Trifid Nebula
Sketch by Kiminori Ikebe

Mr. Ikebe observed and sketched this view of M20 using a 50 cm Dobsonian at 220X.

M20, The Trifid Nebula, is a famous and beautiful target for astrophotographers and visual observers alike. The red emission nebula contains a young star cluster at its center, and is surrounded by a blue reflection nebula that is most noticeable at the northern end. It’s distance is not well agreed upon, and is listed anywhere from 2,200 light years (Mallas/Kreimer) to 9000 light years (Jeff Hester). Its magnitude estimate is also wide, and is listed from 9.0 (Kenneth Glyn Jones) to 6.8 (Machholz). Part of the magnitude difficulty comes from the very bright triple-star system at the heart of the nebula.

The dark nebula that crosses the Trifid was cataloged by Barnard and listed as B 85. The object was originally cataloged by Charles Messier in 1764, when he described it as a cluster of stars.

Marbled Milky Way Magesty

NGC 6604
NGC 6604
Sketch and details by Eric Graff

Object Name: NGC 6604
Also Known As: H.VIII.15, Cr 373, C1815-122
Object Type: Open Cluster + Emission Nebula (Sh2-54)
Constellation: Serpens (Cauda)
Right Ascension (2000.0): 18h 18.0m
Declination (2000.0): –12° 14′
Magnitude: 6.5
Size: 6′ (some sources say 60′)
NGC Description: Cl, lRi, lC
Discovery: William Herschel, 15 July 1784

Date/Time: 4 July 2008 • 09:05 to 10:30 UT
Location: Oakzanita Springs (4,010 ft. elevation), San Diego Co., California, USA
Telescope: Parks Astrolight EQ6 • 6″ f/6 Newtonian Reflector
Eyepiece/Magnification: Parks 15mm Gold Series Plössl • 60x • 52′ FoV
Filters: Lumicon UHC, Lumicon OIII
Conditions: Clear, calm, 62°F
Seeing: Pickering 4-5
Transparency: NELM 6.3; TLM 14.0

If you sweep 1.6° north and slightly west of M16 you’ll chance upon a tight knot of five stars in a glittering field awash with hundreds of stars and marbled with complex swirls of bright and dark nebulosity. This small group (and undoubtedly many of the fainter stars that surround it) comprises the open cluster NGC 6604. The nebulosity (which I found remarkably easy to detect, even without filters) is the southernmost section of a large, but faint, HII region catalogued as Sh2-54. The 7th magnitude lucida of NGC 6604 is an O8 type star that is also an eclipsing binary (of the Beta Lyrae type) designated MY Serpentis. In spite of its spectral type, MY appears yellowish in the eyepiece; this is because the cluster (and nebulosity) is buried deeply in the Great Rift of the Milky Way, severely dimming and reddening its light.

In order to concentrate on the nebula itself, Eric notes: “I sketched the object(s) and a couple dozen of the brightest field stars and background nebulosity. Then, due to the extreme richness of the field I got out printed DSS negatives and started circling the stars I could see (which still took a fair amount of time). These were transferred to the sketches over the weekend. “

Gossamer Stellar Ghost

The Veil Nebula

The Veil Nebula, NGC 6992
Sketch and Details by Rony De Laet

The Veil Nebula

The Veil Nebula in Cygnus can be a tricky object to observe, especially without an OIII filter. This supernova remnant is a delicate complex of faint light that encompasses a 3° field. Starting point for this observation is Epsilon Cygni. From there, go 3° south to find 52 Cygni. A small pair of binoculars can show both Epsilon and 52 Cygni in the same field of view. Now try to move both stars near the western border of the field in order to see the brightest part of the Veil (NGC 6992-6992) in the middle of the eyepieces. I had to use averted vision and a lot of patience to reveal that part of the nebula. The other section, NGC 6960, behind 52 Cygni was not visible at all. I believe that the bright 52 Cygni outshines the weak glow of that part of the Veil. I did have the impression that Simeis 229 or Pickering’s Triangular Wisp could be noted as a tenuous brightening of the sky. Or is it maybe the combined light of an unresolved group of stars at that spot? Detecting the Veil Complex is an interesting exercise, which I should repeat later on the year under darker skies. I do strongly recommend the use of a mount to go after the Veil Nebula. The steady view will allow your eyes to study the star field in greater detail.

Site : Bütgenbach, Belgium
Date : July 1, 2008
Time : around 23.15 UT
Binoculars : Bresser 8×56
FOV: 5.9°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 3,5/5
Transp. : 4/5
Nelm : around 5.8
Sketch Orientation : N up, W right.
Digital sketch made with Photo Paint, based on a raw pencil sketch.

Nothing To Blink At

NGC 6826

The Blinking Planetary, NGC 6826
Sketch and Details by Jeremy Perez

NGC 6826, also known as the Blinking Planetary, was pleasantly bright when I tracked it down at low power. It exhaled a blue-green color at all levels of magnification. At 240X, it displayed a shelled structure with an outer shell that appeared circular while the inner shell was elongated at a PA of about 135 degrees. This inner shell was bright enough to make the central star appear to almost blend into it. I did not notice a blinking effect on the nebula, but detail was lost to direct vision. I estimated its diameter to be about 40 arc seconds. This estimate turned out to be fairly poor, as the actual diameter is 27 x 24 arc minutes. If you’re in the area enjoying M27 and M57, reward yourself a look at this beautiful planetary nebula too.

Object Information:

NGC 6826 was discovered by F.W. Herschel in 1793. High resolution photographs reveal an elliptical nebula with an eye-like appearance. Between the inner and outer shells, along the long axis, two red “FLIERS” can be seen. The cause of these structures is yet to be determined, but Hubble telescope images seem to indicate that these FLIERS are stationary while ejected stellar material flows past them–sculpting them in the process. NGC 6826 is also catalogued as PK83+12.1, H IV-73, h 2050, GC 4514.

Subject NGC 6826
Classification Planetary Nebula (3a(2))
Position Cygnus [RA: 19:44:48.17 / Dec: +50:31:30.4]*
Size* 27″ x 24″
Brightness* 8.8 vMag / 9.8 bMag (Central Star 10.4 mag.)
Date/Time August 13, 2007 – 01:30 AM MST (August 13, 2007 – 08:30 UT)
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 10 mm Sirius Plössl + 2X Barlow (240X)
Conditions Mostly clear, calm
Seeing 4/10 Pickering
Transparency ~ Mag 5.8 NELM
*References NGC/IC Project, Bruce Balick, University of Washington

Seeing Darkness

Barnard 168

Bernard 168
Sketch and Details by Rony De Laet

Barnard 168

The European midsummer nights are not the most favourable nights to go deep-sky hunting. The twilight lasts for the whole night. I had planned to give my attention to some bright galactic clusters. The more delicate objects like faint nebulae should have to wait for darker nights. The NELM for this particular night was around 5.8. I had a few clusters in Cygnus in mind. The last one on my list was the conspicuous M39. When I finished my observation of M39, I tried to see if NGC 7209 in Lacerta was a worthy object for autumn nights. Much to my surprise did I encounter Barnard 168, a thin dark line halfway between M39 and NGC 7209: a dark nebula! It was an unprepared but pleasant visit in the twilight sky. B 168 does not come forward as a void in a crowded field of stars. No, it really shows a darkening as large as 2° in the subtle galactic star glow. While B168 should offer more detail on darker nights, I did make an observation with a sketch under the twilight sky. Maybe other observers with less ideal skies would be encouraged to try their luck as well?

B168 can be found near M39. Put M39 at the western edge of the fov, as shown in the sketch. B168 should be visible near the centre of the field.

Site : Bütgenbach, Belgium
Date : July 2, 2008
Time : around 00.15 UT
Binoculars : Bresser 8×56
FOV: 5.9°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 3,5/5
Transp. : 4/5
Nelm : around 5.8
Sketch Orientation : N up, W right.
Digital sketch made with Photo Paint, based on a raw pencil sketch.

A Celestial Rorschach Inkblot Test

LDN 1795

LDN 1795, a Dark Nebula
Sketch and Details by Dave Riddle

Located only two and one half degrees SE of the Galactic center, LDN 1795 may be one of the finest dark nebulae visible in small telescopes. Appearing as a prominent dark spot in my 11×80 finder, this dust cloud lies in front of the Great Sagittarius star cloud and exhibits an unusual shape as seen through my 18″ reflector at ~110x (20mm Nagler). I saw this inky cloud as either a horse’s head or the head of a Great Dane (making this cloud a kind of celestial Rorschach inkblot test!). John Herschel thought this field to be so extraordinary that he recorded two prominent “clusters” (now recognized as very dense Milky Way fields) in his Cape observation notebook. However, the concept of an obscuring cloud eluded him, although he would later admit that imperfectly transparent regions of space might exist. The idea of dark nebulae can be dated back to the mid-1700’s but it was clearly an idea ahead of its time. The digital drawing was done from a rude pencil sketch I made on the evening of July 21, 1998 from the dark rural skies of Panacea, Florida. As many of you know, drawing a dark nebula presents a challenge to the observer. Photoshop allows me to dispense with my pencil and eraser to make a finished drawing. With practice, I may get it right one of these days (nights)!

Dave Riddle