Category: open clusters

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).

Line of Sight Neighbors

M39

M39 and NGC 7082
Sketch and Details by Rony De Laet

The brightest open cluster of Cygnus is Messier 39. With a diameter of more than a full moon, M39 is a beautiful binocular object. To find this open cluster, just drawn an imaginary line from Deneb (Alpha Cygni) to Alpha Lacerta and point your binoculars at the middle of that line. There you’ll find M39 as a large triangular configuration of 6 brighter stars with a dozen fainter ones. While you have this open cluster in your sight, try to find a neighbour of M39: NGC 7082, at one and a half degree to the south. NGC 7082 is rather dim, compared to M39. My binoculars show only a few faint stars in an elongated misty patch of weak unresolved star glow. M39 and NGC 7082 appear to be close companions, but this an optical illusion. While M39 is 830 light-years from us, NGC 7082 is about 5 times further away. With both objects in the field of view, it is not difficult to imagine that NGC 7082 floats far behind M39 through the night sky.

Site : Bütgenbach, Belgium
Date : July 1, 2008
Time : around 23.45 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.

(Note: if the sketch does look too dark on your monitor, try to darken the room.)

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. “

Arrowhead, Butterfly or Starfish?

M93

M93, an open cluster in the constellation Puppis
Sketch and Details by Jeremy Perez

This is a triangular arrow shaped cluster with its tip pointing southwest. This southwest tip hosts one orange and one yellow star. In the center lies a trapezium-like arrangement of stars. The main body appears to be 16′ in diameter. The brightest neighboring star lies 30′ to the southeast.

Factoids:
M93 lies 3600 light years away and its 80 or so member stars span 20-25 light years across. Its brightest stars are B9 Blue Giants, and its age is estimated at 100 million years. While its stars form a triangular shape, Kenneth Glyn Jones found it to look like a butterfly, while Admiral Smyth found it more like a starfish. It was one of the last deep sky objects discovered by Charles Messier personally and was cataloged in 1781.

Subject M93 (NGC 2447)
Classification Open Cluster
Position* Puppis [RA: 07:44.6 / Dec: -23:52
Size* 22′
Brightness* 6.0
Date/Time February 4, 2005 – 9:15 PM
(February 5, 2005 – 04:15 UT)
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 32 mm (37X)
Conditions Clear, 29�F
Seeing 2/10
Transparency Mag 5.0
Sources SEDS
*Based on published data.

Flocking to Scutum

M11

M11
Sketch and Details by Kiminori Ikebe

M11(NGC 6705) Sct open cluster
Difficulty level 1

Date of observation: 1999/10/06 20:23
Observing site: Makinoto
Transparency/seeing/sky darkness: 3/5/3
Instruments: 32cm Dobsonian with XL14 at 110x
Width of field: 0.6 degree
This is a fine and bright cluster containing many stars. At 110x it is highly concentrated but almost completely resolved. There is a 7.8-magnitude star near the center. It is very conspicuous. There are two faint stars nearby. It is a fine sight with an equal double on the south side, which is as bright as the star near the center. The distribution of the resolved stars is quite uneven. The general shape of the cluster is that of a diamond and a beautiful chain of stars is seen in the southeast outlying area. Dark areas and dense patches of stars are intermingled. There are scattered outliers northeast of the cluster. They seem to be members of the cluster.

The Sparkling Heart of Canis Major

M41

M41
Sketch and Details by Wade V. Corbei

I was able to observe M41 (NGC 2287) on Jan. 18th (early 19th), the ONLY day so far this month that has allowed for any sort of observing.

I was actually quite surprised at this OC that contained quite a few star-chains that only brought more interest, complexity and beauty to this jewel of the night-sky residing within Canis Major. I was fortunate in that my one night of observing was extremely clear and steady, allowing for some great observing of many of the fainter stars within this region.

This sketch, like all others, started out with a plain ol’ mechanical pencil, a #2 pencil & paper (my sketch book). The original sketch was then scanned into and digitized in PhotoShop CS3.

According to my observing notes, I spent a total of 1-hour & 10-minutes at the EP sketching and observing this OC. The longer I gazed at this OC, more star-chains and fainter stars seemed to slowly emrge from the inky darkness. I do rememebr having to stretch a bit after observing and sketching this one.

A Wide Look at M35

M35

M35
Sketch and Commentary by Rony De Laet

While Gemini is far past its optimum appearance in the sky, the view of M35 is still very exciting in a pair of binoculars.

The open cluster M35 was probably discovered in 1745 by Philippe Loys de Chéseaux. In 1764 Charles Messier added the object in his famous catalog with the entry number 35. The cluster has once been called the Shoe-Buckle Cluster for an evident reason. This misty patch can easily be found at Castors foot, between Eta and 1 Geminorum. At a distance of 2.700 l-y, M35 is visible as a mottled, misty patch to the naked eye under very dark skies. It shines with a total magnitude of 5.1.

M35 is a very rewarding object in small binoculars. Once Eta Geminorum is centered in the field of view, the sparkling cluster is easily visible near the western border of the field. I could partially resolve the cluster with my 8×56. Four stars were visible with direct vision, while a total of 14 stars could be picked out of the glow with averted vision. A few dark lanes were visible as well. Unfortunately, the sky was not very clear during the observation and M35 was approaching the north-western horizon. I saw a brightening near the position of NGC 2158, but I could not confirm its presence. M35 is certainly an object to return to next year, when it appears again near zenith. The bright star near the bottom left corner of the sketch is Eta Geminorum.

Observing data:
Date : April 7, 2008
Time : around 20.30UT
Binoculars : Bresser 8×56
FOV: 5,9°
Filter : none
Mount : Trico Machine Sky Window
Seeing : 2,5/5
Transp. : 2,5/5
Nelm : 4,8
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.

Messier 41

M41

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.