The International Space Station and a just-undocked space shuttle Discovery transit the surface of the Sun, appearing near an active spot region, 1166. Credit: Catalin Fus
[/caption]
Amateur astronomer Catalin Fus from Poland has captured one of the most amazing images I’ve ever seen – and his timing was impeccable. On March 7th at 13:05:49 UTC, just after space shuttle Discovery had undocked from the International Space Station, the two ships flew in formation directly in front of the Sun, as seen from Fus’ location just outside of Krakow. With his solar-filtered telescope focused on active sunspot region 1166, he found there were a couple extra spots in his image – Discovery and the ISS. Given that this was Discovery’s final mission in space and final visit to the ISS, this image has historical significance, as well as just being absolutely fantastic. Keep in mind that transits like this last just over a half a second.
He used the following equipment:
Telescope : 102mm f6.3 GPU oilspaced apochromat
self-made Herschel Prism + Meade TeleXtender 2x 1.25”
Mount: Losmandy G11
Camera: Canon EOS 550D
1frame @ ISO 100, 1/1000s
With just a touch of post processing done in PixInsight and PS CS5
Cropped version of the ISS/Discovery/sunspont conjunction. Credit: Catalin Fus. Used by permission.
You can see more Fus’ handiwork at his website, www.catalinfus.ro. Our thanks to Catalin for allowing Universe Today to post his incredible image.
It spans nearly 30 light years of space… and resides approximately 15,000 light-years from Earth. Its heartbeat is an extremely hot giant star thought to be in a brief, pre-supernova stage of evolution. Interactions with a nearby dense, warn and large molecular cloud are what may have contributed to its complex shape and curved bow-shock structure. Step back into mythology and see if you have what it takes to capture “Thor’s Helmut”…
Unlike many nebula, this unusual character is the product of the central Wolf-Rayet star, its stellar winds, and the surrounding interstellar matter. The powerful star emits a high velocity wind, pushing matter ahead of it. This process both compresses and expands its ring-like shell. As it grows, it collects even more gas and dust from the interstellar medium. But how many times and how many events?
“We have detected three different velocity components, and determined their spatial distribution and physical properties. The kinematics, morphology, mass and density are clearly stratified with respect to the W-R star.” says JR Rizzo (et al). “These features allow us to learn about the recent evolutionary history of HD 56925, because the multiple layers could be associated to several energetic events which have acted upon the surrounding circumstellar medium. Hence, a careful study of the different shockfronts contain clues in determining the present and past interaction of this evolved massive star with its surroundings.”
While most planetary nebulae contain old stars nearing the end of their lives, the central Wolf-Rayet star in NGC 2359 is very young. Its ultraviolet photons are the fueling source of the emission nebula. Wolf-Rayets are evolved, massive and extremely hot – up to ~50,000 K. Not only that, but their luminosity is incredible, too… up to 10L to the fifth or sixth power. Their surface composition is extremely exotic, being dominated by helium rather than hydrogen and the stars themselves are rare, simply because they are so short-lived. It was only three short decades ago that astronomers also realized that WRs suffered from heavy mass loss as well. Their ejecta bursts outward at speeds comparable to a nova. The whole process of formation simply isn’t clearly understood yet. The layers may be from differential rotation – but they could be the results of the exposed stellar core.
“The overall emission in the nebula is dominated by the overwhelming contribution of the H II region and is characteristic of photoionization processes. The embedded, photoevaporating cloud contributes enough mass over a dynamical lifetime to account for the shell mass of 5.0 solar mass.” says TE Jernigan. “In NGC 2359, imagery reveals variations in density, temperature, and ionization structure on scales ranging from the size of the nebula down to the seeing limit of approximately 2.1 seconds. The structure of the H II region can be understood in terms of a photoionized conical cavity protruding into the surrounding molecular cloud. The emission in the bubble region is characteristic of that produced in the incomplete cooling region behind a stellar-wind shock wave.”
No matter what explanation lay behind it, observing “Thor’s Helmut” is a pure pleasure. You’ll find it located about a fistwidth east-northeast of Sirius (07h 18m 30s, ?13° 13′ 48″). This Herschel object is a delightful 8th magnitude and well worth the effort!
And many thanks to John Chumack of Galactic Images for making the effort and sharing it with us!
No. You’re not looking at a Hubble image. This incredibly detailed photo was taken with a 14.5″ telescope from right here on the surface of planet Earth. When Allan Sandage turned the Hale telescope its way, he discovered the first Cepheid variables beyond our local galaxy group. At the time he concluded its distance as about 8,000 light years away, but today it is believed to be as distant as 8,000,000. What’s its name? NGC 2403…
Discovered in 1788 by Sir William Herschel, this intermediate spiral galaxy is part of the M81/M82 group… and like its contemporaries, is a product of a galaxy merger. Its northern spiral arm connects to NGC 2404 – riddling the halo with young stars. In this masterful astrophoto done by Warren Keller, the pink and red regions denote active star formation, while clusters of neophyte suns gather in the blue OB associations. Like a fine piece of Irish lace, dark regions appear like holes where dust blocks the light. But NGC 2403 doesn’t follow the rules. Here the galaxy’s arms rotate at a different speed.
“High sensitivity H I observations of the nearby spiral galaxy NGC 2403 obtained with the VLA are presented and discussed. The properties of the extended, differentially rotating H I layer with its H I holes, spiral structure and outer warp are described. In addition, these new data reveal the presence of a faint, extended and kinematically anomalous component. This shows up in the H I line profiles as extended wings of emission towards the systemic velocity. In the central regions these wings are very broad (up to 150 km/s) and indicate large deviations from circular motion.” says F. Fraternali (et al). “We have separated the anomalous gas component from the cold disk and have obtained for it a separate velocity field and a separate rotation curve. The mass of the anomalous component is 1/10 of the total H I mass. The rotation velocity of the anomalous gas is 25-50 km/s lower than that of the disk. Its velocity field has non-orthogonal major and minor axes that we interpret as due to an overall inflow motion of 10-20 km/s towards the centre of the galaxy. The picture emerging from these observations is that of a cold H I disk surrounded by a thick and clumpy H I layer characterized by slower rotation and inflow motion towards the center. The origin of this anomalous gas layer is unclear. It is likely, however, that it is related to the high rate of star formation in the disk of NGC 2403 and that its kinematics is the result of a galactic fountain type of mechanism. We suggest that these anomalous H I complexes may be analogous to a part of the High Velocity Clouds of our Galaxy.”
Does this different rotational curve have an cosmological implications? According to the work of E. Battaner and E. Florido: “We review the topic of rotation curves of spiral galaxies emphasizing the standard interpretation as evidence for the existence of dark matter halos. Galaxies other than spirals and late-type dwarfs may also possess great amounts of dark matter, and therefore ellipticals, dwarf spirals, lenticulars and polar ring galaxies are also considered. Furthermore, other methods for determining galactic dark matter, such as those provided by binaries, satellites or globular clusters, have to be included. Cold dark matter hierarchical models constitute the standard way to explain rotation curves, and thus the problem becomes just one aspect of a more general theory explaining structure and galaxy formation. Alternative theories also are included. In the magnetic model, rotation curves could also be a particular aspect of the whole history of cosmic magnetism during different epochs of the Universe.”
Yet on the other hand, perhaps the differing rotations were caused by the merger itself – with no dark matter involved. “Quite a point has been made about deviations of some galaxies from flat rotation curves, specifically the decreased velocity in outer parts of the curves. Such cases can be explained under the diffusion model by considering collisions and tidal interactions between galaxies. In this explanation, the excess gravitational force is considered to be caused by a “cloud” of the agent that carries gravitational force that always is diffusing freely, although more concentrated in some regions than others as a result of the time required for the diffusion process and the size of the regions involved.” says Roy J. Britten. “When tidal interactions have occurred between galaxies, some momentum could be transferred between stars, gas, and dust that would not be shared by the diffusing clouds, and therefore, asymmetries in the gravitational forces would result. For example, the cloud and galaxies could separate if the two galaxies merged because the galaxies would share their momentum and the clouds would remain independent and continue to diffuse. Then, new gravitational clouds would be built slowly by diffusion from the merged galaxy.”
Dark matter or no dark matter, NGC 2403 (07h 36m 51.4s, +65° 36′ 09″) is a pleasure to observe. Located in the northern constellation of Camelopardalis, this 8.4 magnitude spiral galaxy can be spotted under dark sky conditions with ordinary 10X50 binoculars. In 1954 Fritz Zwicky reported a supernova event and 50 years later it happened again, keeping astronomers wondering about this galaxy with the low-luminosity “dwarf” Seyfert nucleus. SN2004 is the bright yellow “star” in this portrait and it is the closest – and brightest – stellar explosion discovered in more than a decade…
As close as your eyepiece on the next dark night!
Many thanks to Warren Keller of Billions and Billions and David Plesko for sharing their incredible work!
Astronaut Stephen Bowen (inside yellow box) was captured in this image during the March 2, 2011 spacewalk for STS-133. Credit: Ralf Vandebergh
[/caption]
More impressive ground based images of the STS-133 mission, this time, Amateur astronomer Ralf Vandebergh of the Netherlands took images during one of the spacewalks for the mission, and likely captured astronaut Steve Bowen at work on the end of the Canadarm 2! Click on the image above, or go to Ralf’s website for a better view and more information.
Ralf uses a 10 inch Newtonian telescope with a videocam eyepiece, and manually tracks the ISS and other objects across the sky. He takes most of his images in color to obtain the maximum possible information of the objects.
The International Space Station and shuttle Discovery, about 30 minutes before docking. Credit: Theirry Legault.
[/caption]
Award winning photographer Theirry Legault sent us a note about some amazing new video he shot of the space shuttle Discovery getting ready to dock with the space station. Legault took the video on Saturday evening (Feb. 26, 2011) at 18:40 UT from Germany, showing Discovery and the ISS about a hundred meters apart, 30 minutes before docking. The image above is a still frame from the video, which can be seen on Legault’s website here. “It’s sunset on the ISS at the end of the video sequence,” Legault wrote. “The video is accelerated 2.5 times (acquisition at 10 fps, video at 25 fps). The altitude of the ISS is 360 km (200 miles)… and the speed of ISS is 17,000 miles per hour (27,350 kph) and its angular speed at zenith is 1.2° per second.”
Flash is required to see the video. The 900 frames of the sequence has been registered and combined by groups of 10 (processing with Prism and VirtualDub), Legault said. Find out more about Legault’s photography and tracking equipment at this page on his website.
A visible light image from ESO of the reflection nebula Messier 78. Credit: ESO and Igor Chekalin
[/caption]
Here’s another “Hidden Treasure” from the European Southern Observatory, from the astrophotography competition where amateurs create images from unused ESO data. In this new image of Messier 78, brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light and creating what is called a reflection nebula. Almost like fog around a street light, a reflection nebula shines only with the light from an embedded source that illuminates the dust. This image was taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. Comparing this image with others previously taken of Messier 78 shows that remarkably, this object has changed significantly in the last ten years.
Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion’s belt.
For those of you who want to take a look on your own:
Right Ascension: 05:46.7
Declination: +00:03
Distance: 1.6 (kly)
Visual Brightness: Magnitude 8.3
This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds.
Two bright stars, HD 38563A and HD 38563B, are the main powerhouses behind Messier 78. However, the nebula is home to many more stars, including a collection of about 45 low mass, young stars (less than 10 million years old) in which the cores are still too cool for hydrogen fusion to start, known as T Tauri stars. Studying T Tauri stars is important for understanding the early stages of star formation and how planetary systems are created.
Messier 78 region taken in 2006 (below) with the 4-metre Mayall telescope at Kitt Peak, Arizona with a new image from ESO.Credit: ESO/T. A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF and Igor Chekalin
But this object has changed significantly in the last ten years. In February 2004 the experienced amateur observer Jay McNeil took an image of this region with a 75 mm telescope and was surprised to see a bright nebula — the prominent fan shaped feature near the bottom of this picture — where nothing was seen on most earlier images. This object is now known as McNeil’s Nebula and it appears to be a highly variable reflection nebula around a young star.
This color picture was created from many monochrome exposures taken through blue, yellow/green and red filters, supplemented by exposures through an H-alpha filter that shows light from glowing hydrogen gas. The total exposure times were 9, 9, 17.5 and 15.5 minutes per filter, respectively.
I am often asked by people “I’m a beginner, so what telescope should I buy?” Or more often, what GoTo telescope would I recommend for someone starting out in astronomy?
When venturing out and buying your first telescope, there are a number of factors to consider, but because of glossy advertising and our current digital age, the first telescope that people think of is a GoTo.
Do you really need a GoTo or would a manual telescope suffice? In order to make a good decision on what telescope to buy, you need to decide on what you want to use the telescope for — observing, photography, or both and does it need to be portable or not? This will help you make the best decision for the mount of your telescope.
GoTo telescopes are usually advertised as being fully automatic and once they have set themselves up, or are set up by the user, they can access and track and many thousands of stars or objects with just a simple touch of a button. These features have made GoTo scopes are very desirable with many astrophotographers.
Manual telescopes are not automatic or driven by motors as GoTo scopes are. They are predominantly used for observing (using your eyes instead of a camera) and the scope is moved by hand or by levers by the user to find different objects in the eyepiece. Manual telescopes usually have a finder scope, red dot finder or laser finder to aid in finding objects in the eyepiece. They are unable to track objects, which can make them unsuitable for photography.
GoTo Vs Manual
Compared to GoTo telescopes, manual telescopes are much more economical as you are basically buying a very simple mount and an optical tube assembly (the telescope tube, or OTA). With GoTo you are adding electronics and control mechanisms to drive the scope, which can add heavily to the cost. A small GoTo telescope could cost the same as a lot larger manual Dobsonian telescope.
Good GoTo telescopes make astrophotography very accessible and enjoyable, especially with the addition of cameras and other kits. As opposed to manual scopes, GoTos can be used for long exposure astrophotography. Be aware though, that much astrophotography is done with very expensive imaging equipment, but good results can be achieved with web cams and DSLR cameras.
Manual telescopes are brilliant at helping you discover and learn the sky as you have to actually hunt or star hop for different objects. I once met a person who had been using a GoTo telescope heavily for a year, and at a star party I asked her to show some kids where a well known star was with my laser pointer, she didn’t know because she was used to her GoTo scope taking her to objects.
So which one should you buy?
I would recommend for pure visual observing a manual telescope such as a large Dobsonian or Newtonian telescope. The human eye needs as much light to enter it as possible to see things in the dark, so a big aperture or mirror means greater light gathering and more light entering your eye, so you can see more. What you saved by not having GoTo, you can spend on increasing the size of your telescope.
If you want to add photography or imaging capabilities then I would definitely recommend a good quality GoTo scope or mount. You will get a smaller aperture compared to the manual scope for the same money, but the scope will track for astro-imaging and can also be used for visual observing. Be prepared to spend a lot more money, though.
Consider how you want to use your telescope and the size of your budget. Avoid buying low end, cheap, budget, or what is known as “department store” telescopes to avoid disappointment. Save up a little longer and get a good telescope. Visit your local astronomy store or telescope distributor and before you buy ask an astronomer, they will be glad to help.
I hope you enjoy your new telescope for many years to come 🙂 Dobsonian Telescope
Is there any place in the night sky which stimulates our imaginations more than the famous Horsehead? This area of dark dust painted over the smokey veil of emission nebula is one of the most often photographed and visually sought-after regions in Orion. How many of us have used (or bought) a special filter just to see it with your own eyes? Then behold it once again in all of its glory – and all of its mysteries…
“I am happy to present my first image of 2011 with an object that has been long on my target list.” says astrophotographer, Ken Crawford. “This is the famous Horsehead Nebula which is formed by a dark cloud of dust and gas that forms a silhouette against the glow of IC434 behind it. There has been a lot of research done in this region because of the star forming fronts and surrounding molecular clouds with condensing areas that show up as small red clumps. These clumps are glowing red because of the rising temperatures inside are getting hot enough to be seen through the gas surrounding it as they become new stars. These condensing, glowing clumps are called Herbig-Haro objects and can be seen below the Horsehead on the left side and in the cropped image. There is a young new star in the top of the “head” area that sits in a small nebula and has the name B33-1.”
But radiation from this hot star is eroding the stellar nursery. When E.E. Barnard discovered it in 1913, he noted that the edges were “sharp” and “well defined”. Not any more. In just about a century the UV radiation of this O9 star is beginning to show its slow destruction of the cloud…. and that’s not all that is eating away at the familiar equine shape. “We find evidence for a lozenge-shaped clump in the ‘throat’ of the horse, which is not seen in emission at shorter wavelengths. We label this source B33-SMM2 and find that it is brighter at submillimetre wavelengths than B33-SMM1.” says D. Ward-Thompson, et al. “We calculate the stability of this core against collapse and find that it is in approximate gravitational virial equilibrium. This is consistent with it being a pre-existing core in B33, possibly pre-stellar in nature, but that it may also eventually undergo collapse under the effects of the HII region.”
However, destruction is not all this beautiful image reveals. “The bright nebula in the lower left is called NGC2023 and is called a reflection nebula because the blue wavelengths of light are reflected by the dust and gas around the hot blue star.” says Crawford. “There are also Herbig-Haro objects in this active region of star formation. This reflection nebula provides a beautiful contrast of textures and colors that help make the Horsehead nebula one of my all time favorites.”
The bright galaxy NGC 3621, captured here using the Wide Field Imager on the 2.2-metre telescope at ESO’s La Silla Observatory in Chile, appears to be a fine example of a classical spiral. But it is in fact rather unusual: it does not have a central bulge and is therefore described as a pure-disc galaxy.
[/caption]
What could be more eye-catching than a picture perfect pure disk galaxy? In itself it is untouched – not yet combined with a neighboring elliptical or rouge spiral. This is the way we dream of seeing a distant companion… a virgin galaxy awaiting further growth. In a Universe dominated by clusters of galaxies and violent collisions, just how often does a thin, flat plate of stars occur?
According to the ESO Press Release, NGC 3621 is a spiral galaxy about 22 million light-years away in the constellation of Hydra (The Sea Snake). It is comparatively bright and can be seen well in moderate-sized telescopes. This picture was taken using the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. The data were selected from the ESO archive by Joe DePasquale as part of the Hidden Treasures competition. Joe’s picture of NGC 3621 was ranked fourth in the competition.
This galaxy has a flat pancake shape, indicating that it hasn’t yet come face to face with another galaxy as such a galactic collision would have disturbed the thin disc of stars, creating a small bulge in its center. Most astronomers think that galaxies grow by merging with other galaxies, in a process called hierarchical galaxy formation. Over time, this should create large bulges in the centers of spirals. Recent research, however, has suggested that bulgeless, or pure-disc, spiral galaxies like NGC 3621 are actually fairly common. But just how common?
This galaxy is of further interest to astronomers because its relative proximity allows them to study a wide range of astronomical objects within it, including stellar nurseries, dust clouds, and pulsating stars called Cepheid variables, which astronomers use as distance markers in the Universe. In the late 1990s, NGC 3621 was one of 18 galaxies selected for a Key Project of the Hubble Space Telescope: to observe Cepheid variables and measure the rate of expansion of the Universe to a higher accuracy than had been possible before. In the successful project, 69 Cepheid variables were observed in this galaxy alone.
Loading player…
This sequence gives a close-up view of the spiral galaxy NGC 3621. This picture was taken using the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile. NGC 3621 is about 22 million light-years away in the constellation of Hydra (The Sea Snake). It is comparatively bright and can be well seen in moderate-sized telescopes. The data from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile used to make this image were selected from the ESO archive by Joe DePasquale as part of the Hidden Treasures competition.
One of the fascinating things in viewing this image (for me, at least) is seeing all the star-forming regions on the periphery of the galaxy itself. It reminds me of the NGC objects we see in both M31 and M33 (another pure disk galaxy, too). While smaller backyard telescopes are never going to be able to resolve these kinds of details, I can’t help but wonder what larger, professional level equipment can do on a visual level. While I’m at it, my mind also wonders about what we’ve learned recently of the reliability of Cepheid variables as indicators of distance, too. Is this the end all of information? Nah. Because we’re living in a “pure disk” galaxy. Yeah. You heard me right… The Milky Way fits the model, too!
According to a study done by Juntai Shen (Shanghai Astronomical Observatory), et al: “Bulges are commonly believed to form in the dynamical violence of galaxy collisions and mergers. Here we model the stellar kinematics of the Bulge Radial Velocity Assay (BRAVA), and find no sign that the Milky Way contains a classical bulge formed by scrambling pre-existing disks of stars in major mergers. Rather, the bulge appears to be a bar, seen somewhat end-on, as hinted from its asymmetric boxy shape. We construct a simple but realistic N-body model of the Galaxy that self-consistently develops a bar. The bar immediately buckles and thickens in the vertical direction. As seen from the Sun, the result resembles the boxy bulge of our Galaxy. The model fits the BRAVA stellar kinematic data covering the whole bulge strikingly well with no need for a merger-made classical bulge. The bar in our best fit model has a half-length of ~ 4kpc and extends 20 degrees from the Sun-Galactic Center line. We use the new kinematic constraints to show that any classical bulge contribution cannot be larger than ~ 8% of the disk mass. Thus the Galactic bulge is a part of the disk and not a separate component made in a prior merger. Giant, pure-disk galaxies like our own present a major challenge to the standard picture in which galaxy formation is dominated by hierarchical clustering and galaxy mergers.”
Move over, NGC 3621… We’re both commoners.
Many thanks to the European Southern Observatory (ESO) for providing the press release and awesome images!
