Nebula

IC 1396A The Elephant Trunk Nebula

IC 1396, Elephant Trunk Nebula

IC 1396A The Elephant Trunk Nebula L+SHO Version

Distance: 2,400 Light Years
Magnitude: 11.5
Size: 170 Arc-minutes
Age: Approx. 1 million years
Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 1100
Exposures: L 20×600 Bin 1, SII 20×900, Ha 20×900, OIII 20×900

The Elephant Trunk nebula, also known as IC 1396 is found in the constellation Cepheus and is about 2,400 light years away. IC 1396 is one of the larger emission nebula taking up about 3 degrees of sky and containing several star forming regions. The most prominent is IC 1396A which is the part that resembles an elephant trunk. IC 1396A is a dense dark cloud of dust that is illuminated by a very bright nearby star that also illuminates the entire nebula. The bright star is HD 206267 and it is a massive Type O star. The radiation and winds from this star are thought to be the force behind the compression of gas and dust creating the star forming regions. Also contributing to illumination of this area is the open star cluster Trumpler 37 which is seen in the foreground of my image. The glowing edges surrounding parts of the dark globules are formed by the excited gas in the Ha region. This presents the bright backdrop for the globule. In the tip of the Elephant Nebula is a circular globule of dust that is open in the middle. Two stars are found here and they are newly formed stars that have cleared a section of the dust cloud as a process of their formation.

IC 1396, Elephant Trunk Nebula

IC 1396A The Elephant Trunk Nebula LRGB

Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 1100
Exposures: L 20×600 Bin 1, RGB 20×300 Bin 2

IC 1396, Elephant Trunk Nebula

IC 1396A The Elephant Trunk Nebula SHO Version

Telescope: Televue NP101
Camera: QSI 683
Mount: AP 900
Exposures: SII 19×1200, Ha 22×1200, OIII 16×1200

 

VdB 152

VdB 152, Barnard 175

VdB 152

Distance: 1,400 Light Years
Magnitude: 8.8
Size: 5×7 Arc-minutes
Age: Unknown
Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 900
Exposures: L 19×600 Bin 1, RGB 17×300 Bin 2

VdB 152 is a reflection nebula in the constellation Cepheus. It is about 1,400 light years away and is a dim object set in a field of dust known as the Cepheus Flare. Surrounding stars in this area are also discolored as a result of all this dust. BD+69 1231 is the source star that illuminates the reflection nebula and can be seen in the cavity of the nebula. Embedded in this nebula is HH 450, a Herbig-Haro object. Herbig-Haro objects are supersonic outflows from YSO’s that collide with interstellar medium to create compressed lines of material. These show best in images that contain Ha and SII data. It is barely visible in my image but can be seen as a reddish blob to the left of the source illumination star at the dark/reflection nebula boundary. HH 450 is only 33” in length and is only resolved in large telescopes.

Barnard 175 is the cometary-shaped dark dust cloud that tails away from the nebula and is listed as a Bok Globule. A Bok globule is a region of dark cool dust and gas. The densest part of Barnard 175 is approximately 5’ x 7’ in size but the tail extends another 30’. The entire dust complex of Barnard 175 is moving at a different speed than the illuminating source of VdB 152. It was discovered that these two objects are merely passing each other at a speed of 11.7 kms.

The thin red filaments beginning in the upper-left corner of my image and ending at the reflection nebula are the remnants of a supernova explosion. It is cataloged as SNR G110.3 +11.3 and is brightest at the area that intersects VdB 152. This indicates some interaction between the two objects and that their distances from Earth are about the same.

[NOAO, A Search for Herbig-Haro Objects in NGC 7023 and Barnard 175, When Star Birth Meets Star Death: A Shocking Encounter]

 

IC 5146 The Cocoon Nebula

IC 5146, Cocoon Nebula, Caldwell 19, SH2-125

IC 5146 The Cocoon Nebula

Distance: 3,300 Light Years
Magnitude: 7.2
Size: 12 Arc-minutes
Age: Approx. 1 million years
Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 900
Exposures: L 41×600 Bin 1, RGB 29×300 Bin 2, Ha 37×600 Bin 1

IC 5146, better known as the Cocoon Nebula, is an open star cluster surrounded by a combination of emission and reflection nebula in the constellation Cygnus. The source of illumination for this nebula is a young type BO star listed as GSC 3608:1446 and is at the center of the nebula. Most sources state an age of 100,000 years for this star. There are several hundred young stars in this cluster that are about 1,000,000 years old. The difference in age would indicate different stages of star development continuing to the present day.

The red regions are emission nebula illuminated primarily by the central star. The bluish regions are reflection nebula caused by visible light reflecting off dust in the area. The darker regions around the nebula and extending away from the nebula are separate dark nebula named Barnard 168. Barnard 168 is the home to many star forming regions. Many of these regions are in various states of development and as of 2008 there were approximately 200 YSO (Young Stellar Objects) candidates. This count was taken from a paper called “The Spitzer Survey of Interstellar Clouds in the Gould Belt. I. IC 5146 Observed with IRAC and MIPS”.

As a side note, this image was taken from my house in an orange zone.

[Cseligman.com]

Below is the Luminance Channel only:

IC 5146, Cocoon Nebula, SH2-125, Caldwell 19, Barnard 168

IC 5146 Cocoon Nebula Luminance Channel

NGC 6820

NGC 6820, NGC 6823
NGC 6820

Distance: 6,000 Light Years
Magnitude: 6.0
Size: 40 Arc-minutes
Age: Approx. 2 Million Years
Telescope: Takahashi TOA-130
Camera: QSI 683
Mount: AP 900
Exposures: L 16×900 Bin 1, RGB 16×450 Bin 2

NGC 6820 is an emission nebula in the constellation Vulpecula. The most noticeable feature of this nebula is the large elephant trunk structure just below and right of the image center. This large structure gets its shape from the ultraviolet energy emitted from the young star cluster NGC 6823 at the center of my image. The outer regions of this nebula contain many small elephant trunk structures where active star formation is occurring. These stars are very young at 200,000 to 500,000 years which indicates star formation has been triggered after the main star cluster NGC 6823 was formed. This may be due to one of the earlier Type O stars going supernova and the resulting shock wave exciting gas and dust in the outer region of the nebula. There is a small planetary nebula designated as PLN-59.01 to the bottom and right of the image center just below the main elephant trunk structure.

The open star cluster at the center of my image is NGC 6823 and is young at 2 million years. NGC 6823 is also considered the center of the Vulpecula OB1 Association and consists of Type O and B stars which are very young and very hot stars. The high ultraviolet energy from the cluster illuminates the surrounding gas and dust and also shapes the elephant trunk structures. There also Bok globules in the area. These globules are smaller dark clouds of dense gas and dust that are also potential star formation areas. These globules contain hydrogen, helium, carbon, plus silicate and are often responsible for formation of double and multiple star systems. Bart Bok, who first studied these globules in 1940, stated they act like “insect cocoons” as transformational vehicles. He suspected these globules were undergoing gravitational collapse but this was impossible to verify with technology at the time as it was impossible to see inside the dense cloud using images from the visible wavelength. His ideas were later confirmed in 1990 with the use of near infrared images to verify star formation inside.

Below is the luminance image consisting of 16×900 second exposures:

NGC 6820, NGC 6823
NGC 6820

 

Messier 17 The Swan Nebula

M17,Swan Nebula,Omega Nebula, NGC6618,Lobster Nebula

Messier 17 The Swan Nebula

Distance: 5,000 Light Years                                Telescope: Takahashi TOA-130
Magnitude: 6.0                                                        Camera: QSI 683
Size: 11 Arc-minutes                                              Mount: AP 900
Age: Approx. 1 Million Years                              Exposures: L 12×360 Bin 1, RGB 12×180 Bin 2

Messier 17 is an emission nebula in the constellation Sagittarius. M17 is also known as the Omega, Swan, or Lobster nebula and lies in the Sagittarius arm of our galaxy. The illumination sources for the nebula are a group of stars behind the bright central gaseous region. These stars are not seen in visual images but are responsible for the unusual whitish color of this region. At first it would appear that any image of this area is over exposed but the whitish color comes from a mix of the reddish emission gas mixed with reflections of bright star light from the surrounding area. The entire nebula is an active star formation region. Surrounding the bright central region is a large emission cloud. This cloud has a very lumpy structure which indicates future star cluster development.

Above and to the right of M17 is IC 4706 and IC 4707 and these are both listed as stars with nebulosity.

This image was captured in one night from my house located in a Bortle 6 zone. I did try to capture this object two years ago with a 65mm refractor and a DSLR but was not really satisfied with the object or the results. I decided to try it again with a larger scope and CCD camera and I am happy I did. I was pleasantly surprised with the results considering the short exposure times. One thing that did surprise me was the lack of detailed information on M17. I searched several sites and most parroted each other. I then tried Google Scholar and found some more info but not as much as I expected for such a common target.

[SEDS]

 

NGC 6888 The Crescent Nebula

NGC 6888, Crescent Nebula, Caldwell 27, Sh2-105

NGC 6888 The Crescent Nebula Ha+OIII

Distance: 5,000 Light Years               Telescope: Takahashi TOA-130
Magnitude: 7.4                                       Camera: QSI 683
Size: 18×12 Arc-minutes                     Mount: AP 900
Age: 250-400K Years                             Exposures: L 15×900 Bin 1, Ha+OIII 7×900 Bin 1

NGC 6888, the Crescent Nebula, is an emission nebula in the constellation Cygnus. The illuminating source is the Wolf Rayet star WR 136. In general a Wolf Rayet star is a very large hot star that is rapidly shedding mass in the form of ultraviolet radiation. WR 136 is estimated to be 250,000 times brighter than our sun, 15 times more massive, and with a temperature of 70,000 Kelvin. With WR 136, the ejected matter is leaving at a speed of 6.1 million kilometers per hour. This high speed matter hits the ambient dust and gas and gives the Crescent nebula its shape. Part of the surrounding gas and dust is previously ejected material from WR 136 when it was a red giant about 250,000 years ago.

NGC 6888 is a windblown bubble formed by a Wolf-Rayet star that is shedding very hot material in to the surrounding inter stellar medium. It is the gas and dust in the surrounding medium that is compressed in to a thin shell giving the nebula its shape. There are actually two waves of shocked gas, one corresponding to the shocked stellar wind and the other to shocked interstellar gas. The hot interior of this bubble is where the energy is stored and subsequently used for driving the entire structure.

The top image is composed of 900 second Ha and OIII images. The entire area around the nebula is rich in OIII while the interior area is stronger in Ha. This is the first time I tried imaging the Crescent nebula in narrow band and was a bit surprised to see the large OIII ejection area outside of the arc. I did a bit of research on this and a 2014 paper [arXiv:1310.2801v2] said the following:
“The hot gas in NGC 6888 is distributed inside the optical shell delineated by OIII emission. The spatial distribution of the X-ray emission shows enhancements towards the caps and a blowout present in the NW region of NGC 6888. This blowout, not discussed in previous studies, has no Ha counterpart, but an outer skin of OIII is detected. The X-ray emitting gas is, thus, traced by Ha clumps inside the nebular shell and by the blowout. No clear evidence of limb brightening is detected.”

The image below is an LRGB combination captured from my house in an orange zone. The exposures are L 900 seconds bin 1 + RGB 450 seconds bin 2. I was pleasantly surprised that I could get 15 minutes at F7.7 without any difficult gradients.

NGC 6888, Crescent Nebula, Caldwell 27, Sh2-105

NGC 6888 The Crescent Nebula LRGB

 

Messier 16 The Eagle Nebula

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

Messier 16 The Eagle Nebula

Distance: 7,000 Light Years                            Telescope: 10” RC
Magnitude: 6.4                                                    Camera: QSI 683
Size: 7 Arc-minutes                                           Mount: AP 900
Age: Approx. 2 Million Years                          Exposures: L 11×600 Bin 1, RGB 11×300 Bin 2

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.

[SEDS, Wikipedia, NOAO.edu, Universe Today]

NGC 2264 The Christmas Tree Cluster

NGC 2264, Christmas Tree Cluster

NGC 2264 The Christmas Tree Cluster

Distance: 2,400 Light Years                           Telescope: Televue NP101 + .8 Reducer
Magnitude: 3.9 Central Cluster                   Camera: QSI 683
Size: 20 Arc Minutes                                         Mount: AP900
Age: 2-4 Million Years                                      Exposure: SII 2×900, Ha 29×900, OIII 6×900

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.

[Cornell University, SEDS]

Ha Version:

NGC 2264, NGC 2264 Ha, Christmas Tree Nebula Ha

NGC 2264 The Christmas Tree Cluster Ha Version

Messier 57 The Ring Nebula

Messier 57, M57, NGC 6720

Messier 57 The Ring Nebula

Distance: 2,300 Light Years                           Telescope: 10” RC
Magnitude: 8.8                                                   Camera: QSI 683
Size: 1.4 x 1 Arc-minutes                                Mount: AP 900
Age: 6,000-8,000 Years                                    Exposures: L 13×300 Bin 1, RGB 13×150 Bin 2
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]

Veil Nebula

NGC 6992, NGC 6960, NGC 6979, NGC 6974, Pickering's Triangle

Veil Nebula

Distance: 1,470 Light Years                           Telescope: Televue NP101 + .8 Reducer

Magnitude:  8                                                     Camera: QSI 683

Size:  180×180 Arc-minutes                          Mount: AP 900

Age: 5,000-8,000 Years                                   Exposures: Ha 12×1200, OIII 12×1200 For Each Panel

The Veil nebula is a large supernova remnant in the constellation Cygnus. It consists of several nebula each with their own names-> NGC 6960 is the Western Veil, NGC 6992 is the Eastern Veil, Pickering’s Triangle, NGC 6974, and NGC 6979. The entire area is about 3 degrees across at a distance of 1,470 light years. The Veil nebula is the result of a very large star going supernova about 5,000 to 8,000 years ago. The resulting structure is shaped by the very large amounts of energy that form a shock wave that expands into the surrounding space and not only shapes but also illuminates the dust and gas in the area.

NGC 6960, Witches Broom Nebula, Finger of God Nebula, Filamentary Nebula

NGC 6960

NGC 6960, the Western Veil, has several common names. These are the Witches Broom, Finger of God, and Filamentary nebula. The star next to the nebula is 52 Cygni.

NGC 6992, Eastern Veil Nebula, NGC 6995, IC 1340

NGC 6992

NGC 6992, the Eastern Veil, also contains NGC 6995 and IC 1340. The thinner part is NGC 6992 and the first wider part is NGC6995 followed by IC 1340.

Pickering's Triangle

Pickering’s Triangle

Pickering’s Triangle, is the large broom head shaped object between the Eastern and Western Veil. (Some internet sources name this as NGC 6979 but it is doubtful William Herschel meant this object when he discovered this area. Pickering’s Triangle was discovered by photographs at a later date.) NGC 6974 and NGC 6979 are the two smaller nebula with the brighter knots between Pickering’s and the Eastern Veil.

All of the images shown here are captured using only Hydrogen alpha and OIII filters. There is plenty of Sulfur present in this area but I did not like the image color when this filter was added. The mosaic consists of 4 panels consisting of the Eastern, Western, and Pickering’s nebulas plus a filler image to fill in the gap.

[Wikipedia]