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NGC 5139 Omega Centauri

NGC 5139,Omega Centauri

NGC 5139 Omega Centauri

Distance: 16,000 Light Years
Magnitude: 3.68
Size: 36.3 Arc Minutes
Age: 12 Billion Years
Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 900
Exposure: L 20×60 Bin 1, RGB 20×30 Bin2

NGC 5139 is a globular cluster in the constellation Centaurus. It is the largest globular cluster in our galaxy at 36.3 arc minutes in size which converts to 150 light years across. It is also the brightest globular cluster in our Milky Way galaxy and contains about 10 million stars. I was trying to visualize what the sky would look like from a star inside of this cluster and I found a link to a NASA pdf that gave this explanation:

“All of the stars in the image are cozy neighbors. The average distance between any two stars in the cluster’s crowded core is roughly 13 times closer than our sun’s nearest stellar neighbor, Alpha Centauri. Although the stars are close together, WFC3 can resolve each of them as individual stars. If anyone lived on this globular cluster, they would behold a star-saturated sky that is roughly 100 times brighter than Earth’s sky.”

NGC 5139 contains many types of stars at varying stages of development. This indicates many levels of star formation occurring over a few billion years. One possible explanation for this is that NGC5139 is a captured system from another dwarf galaxy. This is supported by a retrograde motion of the cluster and all stars in the cluster have the same proper motion, rotation, and average radial velocity. Typical of most globular clusters, the Omega cluster contains blue stragglers and variable stars. In addition, there are stars along the main sequence like our own sun and red giants.

This cluster has been a goal of mine for the 3 years that I have been imaging. It sits very low in the sky from 34 degrees latitude and is only visible here for about a month. I was very pleased when I slewed to the target and there was a cluster in my field of view! The only problem was that there was a pipe I use for a wind screen that ran right through the frame. The pipe is permanent and I did not want to cut it to get the shot. I think this is what caused the strange shapes of some of the brighter stars. This cluster was captured in one sitting at a dark sky site with a SQM of 20.69. The conditions were excellent with a clear sky, a temperature of 65F, and humidity at 50%. I was surprised how much was revealed with 60 second exposures.

NGC 5053

NGC 5053

NGC 5053

Distance: 56,700 Light Years
Magnitude: 9.47
Size: 10.5 Arc Minutes
Age: 16 Billion Years
Telescope: RC 10” 2000mm FL
Camera: QSI 683
Mount: AP 1100
Exposure: L 11×180 Bin 1, RGB 20×90 Bin2

NGC 5053 is a globular cluster in the constellation Coma Berenices. NGC 5053 appears like a mix of a globular and open star cluster. It is not densely packed even in the core area so it can be easily resolved by large telescopes. A study in 2001 found that NGC 5053 contains 10 RR Lyrae variable stars. An RR Lyrae variable is a star with a pulsating variation in brightness with a cycle of .2 to 1 day. NGC 5053 also contains 28 blue stragglers at last count in 1995. A blue straggler star is thought to be the result of an interaction with another star that leaves the star stripped of its outer layers. This interaction causes the star to appear hotter than what would be possible in an old globular cluster. Another explanation is that they are binary stars in the process of merging and forming a larger hotter star.

An interesting discovery was made while studying NGC 5053. It was found that the cluster was metal poor and dissimilar to other clusters in the Milky Way. One theory for this was that NGC 5053 did not originate in our galaxy but was captured by an ongoing interaction with the Sagittarius dwarf spheroidal galaxy. This makes sense given its location in the intermediate halo of our galaxy. NGC 5053 is not the only globular cluster in the Milky Way acquired from the interaction with the Sagittarius dwarf spheroidal galaxy. Some others are NGC 4147, Palomar 2, Palomar 12, and Whiting 1.

This image was captured from my house in a Bortle 6 zone. It took two nights to capture this image due to the ever present marine layer that is common for May in southern California. The first night I captured all of the RGB data and the second night I was only able to capture 11 frames before the sky fogged over. Conditions were not great with humidity in the 80-90% range.

NGC 4147

NGC 4147

NGC 4147

Distance: 62,900 Light Years
Magnitude: 10.32
Size: 4 Arc Minutes
Cluster Type: Class VI
Telescope: RC 10” 2000mm FL
Camera: QSI 683
Mount: AP 1100
Exposure: L 18×180 Bin 1, RGB 15×90 Bin2

NGC 4147 is a globular cluster in the constellation Coma Berenices. This is a small and compact cluster that resides in the higher latitudes of our galaxy placing it in our galactic halo. NGC 4147 is not very bright when compared to the other 146 known globular clusters in our galaxy, in fact it ranks 112th brightest out of the 146. NGC 4147 is home to several variable stars, some red giants, and also some blue stragglers. However, not a lot is known about the quantities of variable stars in the cluster. At last count in 2005 there were 17 known variables plus another possible candidate. More recently, a renewed interest in NGC 4147 is surfacing because of recent claims that it is the result of a galactic merger with the Sagittarius dwarf spheroidal satellite galaxy.

This image was captured from my home in a Bortle 6 zone with darkness readings of 18.9 magnitudes per square arc seconds and naked eye limiting magnitude of 5.5. The sky was clear but seeing was not that great. The humidity was about 80% during the 2.5 hours needed to capture the LRGB frames. There was no wind.

Messier 27 The Dumbbell Nebula

Messier 27,M27,NGC 6853

Messier 27 Ha+OIII

Distance: 1,360 Light Years

Magnitude: 7.4

Size: 8 x 5.7 Arc-minutes

Age: 3,000-48,000 Years

Telescope: Takahashi TOA-130

Camera: QSI 683

Mount: AP 900

Exposures: Ha 20×1200 Bin 1, OIII20x1200 Bin 1

 

Messier 27 is a large planetary nebula in the constellation Vulpecula. At a size of 4.5 light years across it is a little wider than the distance from our sun to our nearest star. M27 was the first Planetary nebula discovered in 1764 and since then nearly 3000 have been cataloged. The central star of M27 is in the process of dying and as a result has lost most of its outer layers to the stellar medium. What is left is a dwarf star that is very hot and illuminating the ejected gas as it is moving away from the area. Measurements of the expansion rate of the outer layers varies, some have a rate as large as 6.8 arc second per century while others show 1 arc seconds per century. This difference effects the estimated age of the nebula, from as young as 3,000 years to as old as 48,000 years.

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. The central star can have a surface temperature of 20,000K to 250,000K and it is this extreme ultraviolet radiation that ejects the outer layers, shapes them, and illuminates them.

Planetary nebula are great objects for studying how stars such as own will end. In addition, the ejected gasses can be studied for their chemical composition. Furthermore, elements in the gasses are now available for use by the galaxy in future star or planetary formation.

This image was captured from my house in a Bortle 6 zone.

Messier 65

M65,NGC 3623

Messier 65

Distance: 35 Million Light Years
Magnitude: 9.3
Size: 8 x 2 Arc Minutes
Galaxy Type: Spiral Sa
Telescope: RC 10” 2000mm FL
Camera: QSI 683
Mount: AP 1100
Exposure: L 17×600 Bin 1, RGB 18×300 Bin2

Messier 65 is a spiral galaxy in the constellation Leo. M65 is about 100,000 light years in diameter and is home to about 200 billion stars. The bright core area contains mostly older stars and it is thought that star formation is mostly over with the exception of some smaller regions in the arms. Recent studies suggest that the variance in age of the stars from the core to the outer arms is not that great. There is a large dust lane in the outer arm and it contains a few areas where star formation is likely.

M65 is thought to have had some gravitational interaction with nearby galaxies M66 and NGC3628. This interaction has slightly warped the spiral arms of the galaxy. Messier 65, Messier 66, and NGC 3628 form what is commonly known as the Leo Trio. The three galaxies are often photographed together using a wide field telescope. All three galaxies have had prior interactions but it is thought that Messier 66 and NGC 3628 were the most recent.

This image was captured from my house in a Bortle 6 region. The humidity was between 70-80% with little wind. The luminance frame was captured in one night and the RGB was captured on another night. Typical for this time of year is the returning marine layer which flows in before midnight on most nights.

Messier 87

M87,Virgo A,NGC 4486

Messier 87

Distance: 60 Million Light Years
Magnitude: 8.6
Size: 7 Arc Minutes
Galaxy Type: Elliptical
Telescope: 10” RC
Mount: AP 900
Camera: QSI 683
Exposure: L 17×600 Bin 1, RGB 12×300 Bin 2

Messier 87 is an elliptical galaxy in the constellation Virgo. Also known as Virgo A, M87 is a very large elliptical galaxy and appears featureless when compared to spiral and irregular galaxies. At 120,000 light years in diameter it easily surpasses our Milky Way galaxy in size and also in star count. But this diameter is just the main part of the galaxy. When you take in the halo surrounding the galaxy the diameter is close to 1,000,000 light years! Everything about M87 is huge including the 15,000 globular clusters dispersed throughout the galaxy. It is thought that some of these globular clusters were stripped away from nearby galaxies due to past interactions. For comparison, our Milky Way galaxy contains about 200 globular clusters. It has been estimated that M87 is home to several trillion stars compared to about 400 billion star in our galaxy.

At the center of Messier 87 is a super massive black hole that has the mass of 3.5 billion suns. Ejected from this area is a massive spiral jet moving away from the core at close to the speed of light. I was barely able to capture it but for a stunning image captured by the HST click here. This jet is cylindrical in shape but has several knots that appear about 60 parsecs from the core. The jet tapers off much like a puff of smoke at its furthest point from the core.

This image was captured from my home in a Bortle 6 zone with a limiting magnitude of 5.5 and an SQM of 18.9. The sky was clear with humidity varying from 70-85%. This image was captured in one night.

NGC 3628 The Hamburger Galaxy

NGC 3628,Hamburger Galaxy,Leo Trio

NGC 3628 The Hamburger Galaxy

Distance: 35 Million Light Years
Magnitude: 9.5
Size: 14 x 3.6 Arc Minutes
Galaxy Type: Spiral sc
Telescope: 10” RC
Mount: AP 900
Camera: QSI 683
Exposure: L 11×600 Bin 1, RGB 18×300 Bin 2

NGC 3628 is a spiral galaxy in the constellation Leo. It is an edge on galaxy with a dark dusty belt in the middle that is sandwiched by a much lighter halo giving it the popular nickname, the Hamburger galaxy. NGC 3628 has a couple interesting features such as starburst activity and a long tidal tail. The starburst activity was studied in 1996 and it was determined that the source originated near the galaxy core. This starburst activity accounts for accelerated star formation in the galaxy. The long tidal tail was studied in 1998 and was measured at 80,000 parsecs in length with four active star formation regions. The tidal tail also consists of similar material as the galactic core of NGC 3628 leading to the conclusion that it may have originated from NGC 3628. The Hamburger galaxy also contains globular clusters. A study from 2003 that concentrated on listing globular clusters in edge on galaxies came up with a count of 497 +/- 110 globular clusters in the halo of NGC 3628.

NGC 3628 is also part of the Leo Trio of galaxies. This is a trio of galaxies listed as Messier 65, Messier 66, and NGC 3628. All three galaxies are listed at 35 million light years from earth and all three are spiral galaxies. Visually and when viewed with amateur equipment the Hamburger galaxy is my favorite of the three.

This image was captured at a dark sky site with a limiting magnitude of 6.48 with a SQM of 20.86. This image was captured in one night and the conditions were clear and dry but with a steady wind of 5 MPH gusting to 15 MPH.

Messier 51 The Whirlpool Galaxy

M51, M51a,M51b,NGC 5904

Messier 51

Distance: 31 Million Light Years

Magnitude: 8.4       M51a

Magnitude: 10.5     M51b

Size: 11 x 7 Arc Minutes M51a

Size: 5 x 5 Arc Minutes M51b

Galaxy Type: M51a Spiral Sc

Galaxy Type: M51b Dwarf

Telescope: 10”RC

Camera: QSI 683

Mount: AP 900

Exposure: L 11×300 Bin 1, RGB 11×150 Bin 2

Messier 51 is a spiral galaxy located in the constellation Canes Venatici. The spiral arms show well in short exposures and are active star forming regions containing thousands of nebulous areas along with hundreds of young star clusters. A 2011 research paper from Seoul National University has found about 19,600 HII regions in this galaxy. This beats any prior attempts to catalog these areas because the earlier attempts were based on ground observations that limit the resolution (1.8” per pixel) and ability to resolve these small objects. The new counts are based on images from the Hubble Space Telescope which has a resolution of .05” per pixel with a point source FWHM of .1”and can define these areas much better. The image used for the study covered a 7.2’ x 10.2’ area of sky. To put the resolving power of Hubble in perspective, if you could see as well as Hubble and you were in New York City you could see two fire flies one meter apart in San Francisco!

M51 is actually two galaxies that are gravitationally bound with M51a being the large spiral galaxy and M51b as the smaller fuzzier one.

M51a is an active star forming galaxy partly due to its interaction with M51b. Observations show that when M51b passed through M51a it excited the region and accelerated star formation. M51b has moved through M51a from front to rear and will move from rear to front in the future. The theory is that this cycle will continue until both galaxies become one. At question is the timing between these passings but one model suggests 100 million years, another 300 million years, and another at 500 million years. Many new star clusters containing Type O and B stars are located in the spiral arms of M51a and this gives the arms their bluish color. Many reddish nebulous regions are also contained in the arms and this is the fuel for future star generation. The central core of the galaxy contains many of the older stars in the galaxy as indicated by their reddish yellow color. Also noticeable are many dust lanes in the arms.

M51b is classified as a dwarf galaxy (Wiki) even though it is 20,000 light years across (NASA). A 2011 research paper by Seoul National University calls M51b a barred lenticular SB0 galaxy. A 2006 research paper from Seoul National University found that M51b contains a rare type of globular cluster called faint fuzzy star clusters. These faint fuzzy star clusters are much larger than typical Galactic globular clusters and also much redder but are relatively young at 1 billion years. What the authors of this paper also noticed was that their location in the galaxy roughly matched the northern spiral arm of M51a indicating gravitational interaction induced their creation.

As a side note, this is the first galaxy image with my new 10” RC. I kept the exposure times short because of high clouds and humidity. Typical spring weather here!

[SEDS, Wiki, Seoul National University 2006 + 2011, Hubble Site.org]

 

 

Messier 104 The Sombrero Galaxy

Messier 104,M104,NGC 4594

Messier 104 The Sombrero Galaxy

Distance: 28 Million Light Years
Magnitude: 8.0
Size: 9 x 4 Arc Minutes
Galaxy Type: Spiral Sa-Sb + Elliptical
Telescope: 10” RC
Mount: AP 900
Camera: QSI 683
Exposure: L 15×600 Bin 1, RGB 20×300 Bin 2

Messier 104, aka the Sombrero galaxy, is a hybrid elliptical/spiral galaxy in the constellation Virgo. The two most prominent features are the large bright halo and the dust lane across the galaxy. Also prominent in short exposures are spiral arms that are partially obscured by the halo. The classification of an elliptical galaxy with spiral arms was made in 2012 using the Spitzer space telescope. It is not understood how a galaxy can be spiral in shape yet have characteristics of being an elliptical galaxy.

The outer halo contains about 2000 globular clusters which is more than 10 times the amount in our Milky Way. The age of these clusters ranges from 10-13 billion years which is very similar to the ages of the globular clusters in our galaxy. It is estimated that there are several hundred billion stars in M104 spread out over the 50,000 light years diameter of the galaxy. In addition to all of the globular clusters, there have been 294 cataloged planetary nebulas in Messier 104.

The dust lane that forms the brim of the Sombrero galaxy is an active star forming region. Close up images show large open clusters of young hot stars along with HII regions. The dust lane spans the entire 50,000 light year diameter of the galaxy however it is not very deep.

This image was captured from a site with a limiting magnitude of 6.48 and a magnitude per arc second of 20.86. The sky was clear and humidity was about 30%. There was small breeze at times ranging from 3-5 mph. This image was captured in one evening.

Click here for a zoomable image captured by the Hubble Space Telescope.

Messier 106

M106,NGC 4258,Messier 106

Messier 106

Distance: 25 Million Light Years
Magnitude: 8.4
Size: 19 x 8 Arc Minutes
Galaxy Type: Spiral Sb
Telescope: TPO 10”
Mount: AP 900
Camera: QSI 683
Exposure: L 15×600 Bin 1, RGB 17×300 Bin 2

Messier 106 is a spiral galaxy in the constellation Canes Venatici. M106 is also classified as a Seyfert Type II galaxy which means that it emits high levels of ionized gas. This is in part due to the super massive black hole at the galaxy core of M106. M106 has a black hole that is about 10 times larger than the black hole in our Milky Way galaxy but what is unusual about this black hole is it is consuming gas at a much higher rate than ours. As the gas spirals in towards the black hole, it is superheated and emits high amounts of radiation. This takes form as microwave radiation and appears to radiate outward in all directions. M106 has four spiral arms of which two contain active star formation and two that contain superheated gas only. This is unusual and it is thought the black hole is rapidly attracting gas from the core area and ejecting it outward as a superheated gas. Star formation is thought to be 10 times less that what is occurring in our galaxy. It is thought that during this superheating and ejecting of core gas the black hole is starving the galaxy of its star formation material. It is thought that there is enough gas to last another 300 million years.

This image was captured from a site with a limiting magnitude of 6.48 and a magnitude per arc second of 20.86. The sky was clear but there was some humidity after 1am but it dried up by sunrise. This image was captured in one evening.