M16, Messier 16, Eagle Nebula, Star Queen Nebula, IC 4703
Messier 16 The Eagle Nebula

For a full size image click here:

Exposures: L 11×600 Bin 1, RGB 11×300 Bin 2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 7,000 Light Years                           
Magnitude: 6.4                                                   
Size: 7 Arc-minutes                                          
Age: Approx. 2 Million Years                        

Messier 16 is an open cluster in the constellation Serpens. The cluster is very young at 2 million years and was formed from the surrounding gas and dust known as IC 4703. The cluster contains about 460 stars with the brightest at magnitude 8.24. The entire area is commonly known as the Eagle nebula or Star Queen nebula. M16 contains many very hot young stars and the ultraviolet radiation emitted from these stars is the illuminating source of IC 4703. These young stars are also responsible for the shaping of the elephant trunk structures seen in my image. These young stars are Type O stars which are very hot, very large, and emit large amounts of ultraviolet radiation in the form of a solar wind. It is this solar wind which sculpts the shape of the denser dust in the region. It is also the solar wind which can destroy any planet and star formation in the immediate area of newly formed stars by blasting away any remaining gas and dust. This ultraviolet radiation is also giving the entire nebula a hollowed out look as it pushes gas and dust away from the cluster. However, farther out this same solar wind provides an initiation force to stimulate star formation because it shocks and heats cooler gas and dust.

The large dust structures in my image are shaped from the ultraviolet radiation of nearby stars in the cluster. The dark dust structures are commonly known as elephant trunk structures because of their shape. One of the more famous ones is seen in this image and has been dubbed the Pillars of Creation. This area is shown in the middle of my image as a multi-pronged feature. The pillars contain Evaporating Gaseous Globules (EGG) that are smaller denser areas of gas and dust and are thought to be star formation areas. The smaller dust structures outside of these elephant trunk structures are called globules and it is thought that these are future protostars.

NGC 6946, Fireworks Galaxy
NGC 6946 The Fireworks Galaxy

Exposures: L 10×900 Bin 1, RGB 10×450 Bin 2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 10 Million Light Years                 
Magnitude: 8.9                                                 
Size: 11 x 10 Arc-minutes                             
Age: Approx. 10 Billion Years                       

NGC 6946, the Fireworks galaxy, is a spiral galaxy in the constellation Cepheus. It is a relatively large face on spiral galaxy that lies along the galactic plane and it is this view through the galactic plane that presents the rich foreground star field. The asymmetrical shape of NGC6946 may be the result of earlier gravitational interactions with nearby galaxies. Classified as a type Sc galaxy, NGC 6946 has well defined arms containing star clusters, Ha regions, and dust lanes. There is a lot of active star formation in NGC 6946. It is not clear what is causing this as there hasn’t been any recent interaction with other nearby galaxies. One thought is the spiral galaxy has a strong nuclear bar at its core. The bar shape is formed as the orbits of nearby stars become unstable and become elliptical. More and more stars follow this pattern and the bar shape becomes more defined. The formation of this bar is thought to induce star creation in the surrounding gas by concentrating it in the core area.

NGC 6946 is also called the Fireworks galaxy. This is in part because of the high star formation rate but also because of the large quantities of supernovas. From 1917 to 2009 there have been nine supernova, by comparison our Milky Way galaxy averages one per century. There is also a large halo of gas that extends out from the galaxy disk and it is thought that this halo is the ejected neutral gas resulting from the high rates of star formation and supernova.

NGC 2264, Christmas Tree Cluster
NGC 2264 The Christmas Tree Cluster

For a full size image click here.

Exposure: SII 2×900, Ha 29×900, OIII 6×900

Telescope: Televue NP101 + .8 Reducer

Camera: QSI 683

Mount: AP900

Distance: 2,400 Light Years                        
Magnitude: 3.9 Central Cluster                  
Size: 20 Arc Minutes                                        
Age: 2-4 Million Years                                    

Commonly known as the Christmas Tree Cluster, NGC 2264 is actually the catalog number given to the open star cluster and Cone nebula in the constellation Monoceros. The above image also contains the Fox Fur nebula and Snow Flake cluster.

The Cone nebula is the triangular shaped dark nebula in the left center of my image. Behind the Cone nebula is a small emission nebula that provides a contrasting back drop. This area is illuminated by the NGC 2264 open star cluster and also the bright star S Monocerotis. This cluster is blasting away at the Cone Nebula with ultraviolet radiation. There is a beautiful Hubble Space Telescope image that shows this here.

The star cluster NGC 2264 is very young at 2-4 million years. It occupies the area between the brighter star S Monocerotis and the Cone nebula. This cluster contains mainly Type O and B stars but other types of stars are present in their pre main sequence phase. Star formation is still occurring in this cluster as evidenced by a high number of pre main sequence stars that pulsate on their way to becoming main sequence stars. Present estimates of stars in the cluster number about 1,000.

In my image, the Fox Fur nebula is an emission nebula just below the bright star S Monocerotis. This nebula resembles an above view of a fox with its head looking at S Monocerotis. I want to return to this object next winter with a longer focal length telescope. The above wide field image does not bring out the detail that this fine target contains.

Ha Version:

NGC 2264, NGC 2264 Ha, Christmas Tree Nebula Ha
NGC 2264 The Christmas Tree Cluster Ha Version

For a full size image click here.

M92, NGC 6341
Messier 92

Exposure: L 8×240 Bin 1, RGB 8×120 Bin2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 26,700 Light Years                           
Magnitude: 6.4                                                      
Size: 14 Arc Minutes                                            
Cluster Type: Globular Class IV                     

Messier 92 is a class IV globular cluster in the constellation Hercules. M92 is estimated at 14 billion years in age and thought to be the oldest globular cluster in the galaxy. This age estimate is partially based on the low metallicity counts in the stars of M92. Low metallicity indicates that the globular cluster was formed very early from gas and dust that was not yet enriched with metals.

M92 has 24 variable stars as of July 2012. [Christine Clement’s Catalog of variable stars in M92] Of these 17 are classified as RR Lyrae type variables. The other 7 are type SXP which is short for SX Phoenicis, a type of variable star with low metallicity and very short periods. M92 also has blue straggler stars with the heaviest concentration in the center of the cluster. A blue straggler star is a young hot star that is thought to have formed from an interaction with another star. During this interaction, the stars shed material and the cores merge to form a new star.

M92 will be within 1 degree of the North celestial pole in about 14,000 years. This will be the result of the Earths 25,772 year precession cycle.

M12, NGC 6218
Messier 12

Exposure: L 7×240 Bin 1, RGB 7×120 Bin2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 16,000 Light Years                     
Magnitude: 6.7                                                
Size: 16 Arc Minutes                                     
Cluster Type: Globular Class IX               

Messier 12 is a globular cluster in the constellation Ophiuchus. Like all globular clusters, M12 is very old at 13 billion years. M12 contains about 200,000 stars but what is unusual about M12 is that it missing a lot of the low mass stars typically found in globular clusters. One explanation is the galactic orbit of M12 takes it closer to the galactic core than many other globular clusters. As M12 moves through the core area the lower mass stars are stripped away by the massive gravitational pull of the dense core area. This could explain the Class IX rating given to this cluster. The Class IX rating means that M12 has a loosely concentrated core area.

M12 is home to variable stars, blues stragglers, and red giants. What is unusual is that M12 only has 13 variable stars which is a small quantity for globular clusters. M12 is also populated with blue stragglers which are younger hotter stars that have formed as a result of interaction with other older stars. The red giants are large cool stars that are at the end of their lifespan.

M5, NGC 5904
Messier 5

Exposure: L 10×240 Bin 1, RGB 10×120 Bin2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 24,500 Light Years                        
Magnitude: 5.6                                                    
Size: 23 Arc Minutes                                         
Cluster Type: Globular Class V                    

Messier 5 is a large globular cluster in the constellation Serpens. At 13 billion years old it is one of the older globular clusters. It is also fairly large at 23 arc minutes but the majority of the cluster extends out about 17 arc minutes. Like most globular clusters, the stars in M5 were formed at about the same time. The largest short lived stars went supernova early in the clusters life cycle and blew out the remaining gas and dust in the region effectively removing the material for future star formation. The remaining stars fell along the main sequence and were smaller and cooler. This cluster also has many RR Lyrae variable stars and a large amount of Blue Stragglers. The RR Lyrae variable star is a star that fluctuates in brightness over a regular period. To date, 97 RR Lyrae variables have been cataloged. The blue stragglers are stars that are bluer and hotter than the surrounding stars in the cluster. This should not happen in a globular cluster as all stars are formed at about the same time. One theory is two stars had an interaction where they lost outer layers and merged in to one newer hotter star. Another theory is that the two stars had an interaction where one’s outer layers were stripped donating this material to the other star.

Globular clusters are rated according to the distribution of their stars. This rating system was formed by Harlow Shapley and Helen Sawyer Hogg and is known as the Shapley-Sawyer Concentration Class. The ratings use Roman Numerals starting at I and ending at XII. Roman numeral I is used for globular clusters with most of their mass at the core with little surrounding stars away from the core. Roman numeral XII is used for globular clusters with a very loose core with minimal structure. M5 is classified as a Class V globular cluster which describes the cluster as having intermediate concentrations of stars.

Messier 53, M53, NGC 5024
Messier 53

Exposure: L 10×240 Bin 1, RGB 10×120 Bin2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 58,000 Light Years                                        

Magnitude: 7.6                                                                    

Size: 13 Arc Minutes                                                        

Cluster Type: Globular Class V                                  

Messier 53 is a class V globular cluster in the constellation Coma Berenices. At a distance of 58,000 light years its 13 arc minute diameter translates to about 220 light years in diameter. It is one of the furthest globular clusters from the galactic center at 60,000 light years. Like most globular clusters this cluster is populated with many older stars, RR Lyrae variables, and blue stragglers. All stars in globular clusters form at about the same time so they should be about the same age. The discovery of younger blue stars threw a wrench in to the conventional thinking. Why where there younger hotter stars in the cluster? One theory about blue stragglers is that they are stars that have been stripped of their outer layers through interaction with other stars leaving a hotter core. Another theory is that two stars have merged in to one giving the appearance of a younger hotter star. The RR Lyrae type variable stars are also a common feature in globular clusters and these variables typically have a short period. Named after the first discovered variable star of this type, RR Lyrae, these variable stars are about half the mass of our sun, older than our sun, and also hotter than our sun. The variation in brightness is due to the increase and decrease in size of the star as its outer layers pulsate. The variable star will be brightest at its smallest size and dimmest at its largest size. These periods can be timed with great accuracy.

Messier 13, M13
Messier 13

Exposure: L 14×300 Bin 1, RGB 14×150 Bin2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 25,100 Light Years                                        

Magnitude: 5.8                                                                    

Size: 20 Arc Minutes                                                        

Cluster Type: Globular Class V                                  

Messier 13 is a large Class V (medium star density) globular cluster in the constellation Hercules. This cluster contains over a million stars* and shows well in short exposure images. M13 is very old at 14 billion years but contains some blue straggler stars which indicate much younger stars. One theory about blue straggler stars formation says they are older stars that have merged together from gravitational interaction and as a result are hotter that the surrounding stars. Another possibility is the stripping of outer layers from the star from interaction with other stars.

*Kevin Tran UC Davis July 29, 2009 reports over a million stars

Like all globular clusters, the stars of M13 formed about the same time and are about the same age. We know this because many of the earliest stars of globular clusters were very large and had a very short lifespan. During their demise they went supernova and blew any remaining gas and dust out of the area thereby depriving the area of any materials for star formation. What is left after these first few million years is the smaller stars that fall in to the main sequence and these are what we see today. The star density in the core area is very dense. There are several hundred thousand stars within a 6 parsec area around the core. In contrast, the nearest star to our sun is 1.3 parsec away. Could you imagine what the day and night sky would look like from a star near the core of M13? It would be awesome!

[Michael Warren McCutcheon, Department of Physics, McGill University, Montreal, April 11, 2011]

Messier 3, M3,
Messier 3

Exposure: L 10×180 Bin 1, RGB 10×90 Bin2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 33,900 Light Years                                              

Magnitude: 6.2                                                                          

Size: 18 Arc Minutes                                                              

Cluster Type: Globular Class VI                                        

Messier 3 is a globular cluster in the constellation Canes Venatici. M3 shows well in short exposure due to its large size and it is also fairly bright at magnitude 6.2. There are about 500,000 stars in this cluster with a dense core of about 12 arc minutes diameter with reduced density out to about 18 arc minutes diameter. The age of the cluster is about 8 billion years and it is 33,900 light years away. This cluster contains a large amount of variable stars and also blue straggler stars. Over 200 variable stars have been cataloged and most are classified as RR Lyrae variables which have regular periods of less than one day. Blue stragglers are older stars that are much hotter than the surrounding stars. This is unusual in globular clusters as all stars form at about the same time and therefore should be fairly uniform in age. One theory about blue straggler star formation says they are older stars that have merged together from gravitational interaction and as a result are hotter that the surrounding stars. Another possibility is the stripping of outer layers from the star from interaction with other stars.

Messier 57, M57, NGC 6720
Messier 57 The Ring Nebula

Exposures: L 13×300 Bin 1, RGB 13×150 Bin 2

Telescope: 10″ RC

Camera: QSI 683

Mount: AP900

Distance: 2,300 Light Years                         
Magnitude: 8.8                                                 
Size: 1.4 x 1 Arc-minutes                               
Age: 6,000-8,000 Years                                  


Messier 57 is a small Planetary nebula in the constellation Lyra. Although it is very small the outer rings show brightly in short exposures. I took some time during processing trying to control the brightness of the outer ring while not washing out the core area that houses the central star.
Planetary nebula are formed from stars with solar masses of 1-8 times that of our sun. This is really a dying star that is too small to go supernova. Its death spiral begins with a shedding of outer layers that are ejected from the surface. This shedding of gas is the result of gravity overpowering the internal pressure created by fusion. As the star exhausts its hydrogen it is forced to use other elements until this higher pressure can no longer be maintained. At this point the star begins to shed its outer layers while the remaining layers start to collapse causing the core to heat up. This heating is the source of illumination for the ejected gas. The ring shape of M57 consists of gas shed from the outer layer of the dying star at the center of the nebula. The star will be a white dwarf at the end of this process. Observations over the last 100 years have shown this gas ring has been expanding and it can be estimated from the expansion rate that the age of the nebula is 6,000 to 8,000 years. The study of Planetary nebula tells a lot about the dying star. The ejected gas can be analyzed to see which elements are present as these elements were once part of the star.
[SEDS, Williams.edu]