open clusters – Page 31 – Astronomy Sketch of the Day

One Wild and Distant Duck

The Wild Duck Cluster, M11
By Jeremy Perez

M11 holds a special place for me. It was the first deep space object I viewed through the new telescope–besides M45 & M31 which I had seen before. It was very exciting to see something with my own eyes that prior to that night I never even knew existed. It was a symbol for me of what else lies in the sky that I don’t yet know about. Beautiful. A striking collection of stars. I revisited it this night under less than perfect conditions. It was diving into some of the worst light pollution from my home vantage point. Oh, and the moon was starting to rise. It demonstrated dense and mottled granularity, with numerous resolvable stars winking in and out across the surface. (Did I mention seeing was really bad too? 3/10. Right.) Anyway, one bright star dominates the center of the cluster, and 2 others close stars reside just outside to the SSE. (It should be noted that these bright stars are actually foreground stars, and aren’t part of the cluster.) The overall shape of the cluster is circular with a central cloud surrounded by a gap, and then a rough ring of stars. OK. I know I’ve said this before, but once more for emphasis: to me, the “Wild Duck” name doesn’t just look like a V-shaped ‘flock of ducks’, but actually looks like a duck raising it’s wings to take to flight, with the head at the SW side of the central concentration of stars, and the wings curling around on the NW and SE sides. The dimension of the main body of the cluster appeared to be 7′ across.

Factoids:
M11 is one of the richest and most compact of the open clusters. It is 6,000 light years away, and contains around 2,900 stars. If our planet were in the midst of this cluster, we would see several hundred brilliant first magnitude stars scattered across the night sky. Amateur astronomy would probably be pretty tough in a sky so brightly lit at all times. M11 was discovered in 1681 by Gottfried Kirch, first resolved into stars in 1733 by William Derham, and then included in Charles Messiers catalog in 1764. Its age is currently estimated to be 250 million years, and it is receding from us at 22 km/sec.

A Brooch in the Horns of the Bull

NGC 1647
By Jeremy Perez

Observation Notes:
I first noticed NGC 1647 between the horns of Taurus in a wide-field astro photo I shot of the area in November 2005. I had been meaning to observe and sketch it since then. At 37.5X magnification, the cluster appeared large, bright and sparse. Two colorful yellow and yellow-orange stars rested at the south side of the cluster. I noted several doubles within. The diameter of the main body of the cluster appeared to be about 30 arc minutes. Several bright Orionids graced the sky and caught my attention during the observation and sketch.

Object Information
NGC 654 was discovered by Friedrich Wilhelm Herschel in 1784. According to Catalogue of open cluster parameters from UBV-data. (Loktin+, 1994), the cluster is about 509 parsecs distant (1,660 light years). Star Clusters and Associations, Selected Data (Alter+ 1970) lists a distance of 550 parsecs (1,790 ly). The cluster is also catalogued as Cr 54, Mel 26, OCL 457, Lund 139, H VIII-8, GC 896.

Jewels at the Feet of Gemini

M35 (NGC 2168)
By Wade V. Corbei

Visible to the naked eye under good sky conditions, M35 resolves into a nearly circular mass sparkling with stars, even with small aperture instruments. The cluster consists of 400-500 stars with 120 brighter than magnitude 13. It is 2700 to 2800 light years distant with a diameter of about 24 light years. It is estimated to be about 100 million years old and contains several yellow and orange giants. The cluster is approaching us at 5 km/sec. It was discovered by Philippe Loys de Chéseaux in 1745-46, independently rediscovered by John Bevis before 1750, and finally cataloged by Charles Messier in 1764.

Source: SEDS

The Moon Over Georgia

The Moon Over Georgia
By Carlos E. Hernandez

I was treated to a beautiful sight of the Waning Gibbous Moon (14.1 days old) rising over the northeast horizon of my son’s home in Georgia (Grantville, southwest of Atlanta) on November 24, 2007 (01:30 U.T.). The clear and dark skies accented the Moon above Taurus (Aldebaran) and Auriga (Capella) below it. I was inspired to render what I saw.

A digital image produced in Corel Painter X.

Carlos

Salt and Pepper in Cassiopeia

M52 (NGC 7654) Cassiopeia Open Cluster
By Kiminori Ikebe

Difficulty level 1
Date of observation: 2002/01/05 20:30
Transparency/seeing/sky darkness: 2/2/3
Instruments: 32cm Dobsonian with XL21 at 70x
Width of field: 0.9 degree
This cluster is situated west of Cassiopeia’s letter W. It is fairly bright. Although it is a mid-size cluster, stars are well concentrated and individual member stars are bright and beautiful. At 90x it is almost fully resolved. A 7.9-magnitude star in the west stands out. There are many bright stars in the northwest. In the east there is a small condensation from where lines of stars extend outward. Also, a line of stars running from the center to the southeast attracts an observer’s attention. There is a triangular-shaped clump in the southeast somewhat detached from the cluster. There are many faint stars sprinkled in the outlying areas.

Mr. Ikebe’s sketch gallery can be found here: Visual Observation of Deep Sky Objects

Eta Carinae from Haleakala

Eta Carinae Complex and NGC 3293
By Jeremy Perez

Move mouse over image to see labels. Click for larger image.

The observing highlight of an evening atop the summit of Haleakala in Maui was gazing through my binoculars at the rich starscape in the vicinity of Eta Carinae. I had not done any homework on the area beforehand, so I approached it with unexpecting eyes. The mottled depths of the surrounding Milky Way, the smattering of intensely bright foreground stars, the abundance of open clusters of all shapes, sizes and intensities, and the stunning patches of glowing nebulosity made the whole region a delicious feast for the eyes. One incredible open cluster to the northeast, nearly took my breath away, but I did not have time to even attempt a sketch of it. Instead, I chose to render the region bracketed by the Eta Carinae complex and a much more manageable cluster, NGC 3293.

Eta Carinae was a brilliant orange star that surrounded itself in a plush comfort of nebulosity. This misty region ended abruptly to the south and then emerged again to surround a trio of bright stars. The observation and sketch were done more hastily than I would have liked and I know there was more detail to be extracted from this bright nebula, but I took what I could get. The northwest side of the view was punctuated by the small, bright open cluster, NGC 3293. Four bright stars announced themselves within its glowing boundary of unresolved starlight.

This section of the sky is still beckoning me, and I know I will have to return to it again with more time to spare. Even if I only have binoculars again the next time, it will still offer more than I can possibly absorb.

The sketch was created on Strathmore sketch paper with 2H and HB pencils. Nebulosity was shaded with a blending stump loaded with graphite. Color was added to Eta Carina in Photoshop.

Object Information

Eta Carinae is one of the most massive stars in the universe and is likely greater than 100 solar masses. It is about 4 million times more luminous than the sun, but radiates 99% of this energy in the infrared. Due to its extreme mass, it is expected to go supernova within the next few hundred thousand years. In the meantime, as it rapidly sheds matter, it goes through sporadic, violent outbursts. The most recent outburst peaked in 1843 when Eta Carinae became a magnitude -1 star, second only to Sirius. This eruption generated a rapidly expanding plume of gas that now forms a fascinating dumbell shape.

A Calculating Cluster

NGC 2169 – The 37 Cluster

By Wade V. Corbei

NGC 2169 is an open cluster located near the apex of Orion’s raised eastern arm. It has become known for an asterism of stars within it that appear form an angular representation of the number 37. NGC 2169 lies 3600 light years away and is receding at about 16 km/sec.*

*Source: SEDS

A Cluster on the Doorstep of the Trifid

M21
By Wade Corbei

This is an Open Cluster found in Sagittarius that contains a lot of stars of varying magnitudes, and lies close to M20 (Trifid Nebula). According to my notes, this OC was completed over the course of two evenings due in part to its location in the sky. It slipped behind some trees to my south on the first night, so I had to finish the sketch the following evening. Total sketching time at the EP was, I believe, approximately 1.5 hours.

A nice OC that fills up the entire FOV in a low-power EP.

A Promenade Through a Royale Garden

IC1396, a promenade through the Royale Garden.

One of the known highlights of Cepheus is Mu Cephei, a deep orange star. This night Mu Cephei served as the guiding light to IC1396. This region is a beautiful field of stars. There was something peaceful about this place. I felt like strolling through an exotic garden covered with haze. The place seemed majesticaly silent with Mu Cephei as a guard of honour at the border of the eyepiece. I don’t know if I saw IC1396 at all. I just noted all the light I could absorb in this field. A strange fact is that Mu Cephei kept his orange color through the UHC filter.

Date : October 13, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
Meade SP 26mm
Power : x20
FOV: 150′
Filter : Lumicon UHC
Seeing : 3.5/5
Transp. : 3/5
Nelm : 5.3
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.

Rony De Laet
Belgium

ET Phone Home

Here is my impression of NGC 457, a little funny guy that seems to swing through space with his arms stretched to get hold on some stars. The night was not very dark. The milkyway was only visible in the cygnus region. While centering the cluster, there appeared a small glowing patch to the north west. I did not know what it was, probably an anonimous grouping of stars. It turned out that the patch was NGC436, at about 40′ ! It came as a nice surprise.

Date : October 16, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
Meade SP 26mm
Power : x20
FOV: 150′
Filter : none
Seeing : 3.5/5
Transp. : 3/5
Nelm : 5.1
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.

Rony De Laet
Belgium

http://www.geocities.com/rodelaet