SLOOH Skylog

Like so many of us, Charles Messier became interested in the universe, and especially our galaxy with all its bright celestial objects, as a youngster. (Lucky boy, not much light pollution in his time.) Charles carried this interest forward to become an astronomer in Paris, where, among many other accomplishments, he gained lasting recognition for his catalog of clusters, nebulae, and galaxies. That catalog is the “M” series of heavenly bodies, and it is still in use today.

Interestingly enough, Messier’s first passion was comets (he discovered 20) and yet, his catalog is a meticulously-recorded collection of other important celestial objects. These objects have come to be so well-known, in fact, that they are an integral part of Slooh’s own collection of regularly-featured targets.

Initially, Charles Messier was convinced that the first entry in his catalog, noted as M1, was a comet. But, as the world would eventually learn, M1 was not a comet at all. It is a nebula that evolved from a supernova observed some 950 years ago - or about 700 years before Messier discovered her. (I say “her” because I find this celestial wonder quite beautiful, entrancing, and definitely a bit mysterious.)

M1, the exotic Crab Nebula, was first observed and recorded as an actual supernova by Chinese astronomers in 1054. Additionally, petroglyphs from the Anasazi cliff dwellings in New Mexico and Arizona seem to indicate that they, too, sighted the supernova or, at least, were told about it and recorded it. And although Charles Messier’s independent discovery of the Crab Nebula gets most of the attention, it was actually John Bevis who first discovered and cataloged the object in 1731, twenty-seven years before Messier’s discovery.

Because of the vast distances of space, we witness events long after they actually occur. So, using my handy time/distance calculator and the Chinese year of discovery, I approximate that the M1 supernova occurred around 5000BC or about 6000+ years before the Chinese saw the event. SEDS reports the Crab Nebula’s distance as 6300 light years. You can try calculating this time interval yourself. Click on the time/distance link above to launch the calculator.

Enough history - lets talk about the Crab. First, here she is in all her glory, compliments of Slooh’s Teide 1 High-Mag telescope and the Slooh members.

I selected this image because it shows both the crab-like filaments of the nebula and her mighty pulsar. We will get to the pulsar below, but first some details about the Crab Nebula.

Because it resulted from a supernova (material is moving out and away,) the Crab is ever-expanding at the rate of 1800 km/sec. So, the Crab you view today will not be quite the same when your great-grandchildren view it. Meanwhile, as you look at the image of the nebula, you can, with some imagination, see her resemblance to a crab; but the real source of her name comes from an 1844 drawing by William Parsons, the Third Earl of Rosse. Go ahead and click on the link to see Lord Rosse’s drawing. You can see that it clearly resembles a horseshoe crab - a creature with its own prehistoric lineage.

The Crab Nebula is important for several key reasons. Her traceable history, from her explosive origins to what we see today, provides important data about the evolutionary processes that follow supernova events. Additionally, the 1968 discovery of the Crab Pulsar added another important research element to be studied. In fact, within professional astronomy circles, there is a rumored division between those who study the Crab Nebula and those who do not.

The Crab Pulsar is an amazing and powerful neutron star. Neutron stars evolve from stars that have masses 4 to 8 times greater than our sun. They are the products of supernovas and often remain as part of the remnants. Some neutron stars have fast-moving jets streaming out above their magnetic poles. These jets produce very powerful beams of light that sweep around as the star rotates. These sweeping beams are detected as varying radio frequencies or pulses; thus, we call these stars “radio pulsars.”

Pulsars are found both within and without supernovae remnants. When associated with a remnant, as is the Crab’s pulsar, the nebula is further categorized as a pulsar wind nebula. In fact, scientific data states that the Crab Nebula is much more a pulsar wind nebula than it is a supernova remnant; and because it was the first such object discovered, M1 is the prototype. Of the more than 1600 known radio pulsars, less than 40 are associated with nebulae. In the Slooh image above, you can see the Crab’s pulsar as that fuzzy star-like object directly beneath the nebula’s bright center region.

Fun Facts: * Neutron stars are so dense, just one teaspoonful would weigh one-billion tons on Earth. * The Crab Pulsar contains a mass equal to our sun crammed into an object just twelve miles wide. * The Crab Nebula measures 10 LY across - that’s 58.8 trillion miles or 94.6 trillion kilometers.

I could tell you much more about the Crab Nebula, but I’d rather encourage each of you to dig deeper on your own. You can start by observing the Crab Nebula, either through Slooh’s Editor Channel or by reserving a slot on the Member Channel. The Editor Channel schedule can be found here in the Slooh User Forums, and guidelines for reserving your own Member mission can be found here in the Slooh Help & FAQ. If you need direct assistance, simply pop into the Slooh ChatRoom where you can ask questions in real-time.

As a “Focus On” bonus, we’ll feature the Crab Nebula with a Slooh Mission Alert later this week. We’ll target it through the Slooh telescopes with three back-to-back missions and talk more about it with special commentary on SloohRadio. Watch the Launchpad banner or Slooh Twitter Feed for more details.

NOTE: Currently, a Mission Alert is scheduled for Thursday, Nov. 20, 8:30pm EST / 01:30 UTC - weather permitting.

NOTE: Thursday’s Mission Alert has been rescheduled to Saturday, Nov. 22, 8:30pm EST / 01:30 UTC - weather permitting.

Look up, always, and dark, clear skies for all. And don’t forget to check back next month for another installment of “Focus On.”

The holiday season is upon us again! In this SloohRadio Podcast of  Phil Harrington’s “Star Watch,” Phil explains what to look for in a new telescope by considering the budget, recipient’s age, experience with astronomy, and of course, the size of their car! In addition to some specific manufacturers’ recommendations, Phil also explains what to avoid when buying a ’scope and gives sound fundamentals to the selection process.

While this is well-timed for the holidays, Phil’s advice is valuable for any occasion where you want to purchase a new telescope (including one for you!) He also talks about the joy we all share when we have both our own equipment and the unique experience of Slooh.

This podcast is available for download below, and is also published on ITunes and all major podcast listings.  Remember you can subscribe to our podcast feed from ITunes for automatic delivery of all SloohRadio Podcasts.

Keep Looking Up!

 

 Phil Harrington's Star Watch 11/9/2008 - Slooh Radio [62:22m]: Play Now | Play in Popup | Download (78)

To inaugurate the publishing of selected SloohRadio episodes here on the Slooh Skylog, we picked a great recent episode of Bob Berman’s Monday night SloohRadio classic, “Bob Berman’s Strange Universe.” Those of you who’ve been around awhile know that Bob’s show has been a regular feature here on Slooh (with a few interruptions!) since almost the beginning.

In this episode, Bob interacts with the Slooh Chat Room to explore a wide range of topics including:

• The nature of space. What we think is empty…isn’t!
• Commentary on Slooh Missions as they happen (audio only, but video in the future!)
• The causality of certain Earth phenomena and the possible role of the Moon.
• The official Bob Berman pronunciation guide for the 20 brightest stars.
• “Stump the Chat Room” where Bob challenges the Slooh members to identify sometimes-obscure astronomy and physics terms.

As always, Bob employs his frenzy of factual connections and insights to show us that the Universe is a graceful place after all.

You can link directly to the podcast using the links at the end of this article. Even better, you can subscribe to this and future podcasts using a number of techniques:

1. If you use ITunes, simply search for “Slooh” in the Podcast section of the ITunes Store or click here  (don’t worry, Slooh podcasts are free!). Once you find the entry, click on the subscribe button. Anytime we publish a new podcast, ITunes will automatically download it and, if so equipped, sync it to your IPhone or IPod.
2. For other “Podcatching” software, simply point it to: http://www.slooh.com/blog/?feed=podcast

For now we will be publishing podcasts here on the blog. Eventually, we’ll move them to an archive page for future posterity.

Watch for more podcasts, and even video podcasts, in the near future; and of course, Keep Looking Up!

 

 Slooh Radio Bob Berman's Strange Universe 11/03/2008 [66:12m]: Play Now | Play in Popup | Download (106)

For a third straight week, we have yet another opportunity to observe a near-Earth object, this one passing at just 4.1 LD on October 29th!

NEO 2005 VN is a 100m (300ft) asteroid discovered in 2005, a mere two days before passing within 17 LD of our planet. That discovery was made by LINEAR on November 2, 2005.

The last quarter of that year, 2005, was a busy time for discoveries in our near-Earth neighborhood, with several objects being discovered only after they had passed our planet. While a handful were small meteoroids, measuring anywhere from 5m to 30m, as many others were larger asteroids measuring many tens of meters to as much as 1km.

One of the smaller objects, 2005 WN3, actually passed less than a quarter the distance of the moon just seventeen hours after its discovery. The very next day, another small object, 2005 WY, passed at only 2LD six days after its discovery. Then, ten days later, yet another small object was discovered just two days before passing within a mere 0.6LD.

All totaled, the months of October, November, and December of that year saw fifty-five new discoveries, with a dozen of those objects passing less than 10LD from Earth, several of them before they were even discovered.

Our latest NEO, 2005 VN, will be featured with two Mission Alerts on Tuesday night, at 20:25 UTC and 22:00 UTC - that’s 4:25pm EDT and 6pm EDT. We’ll target it through the Slooh telescopes as it slips through the constellation Draco; and we’ll talk about its discovery, as well as several others in those last few months of 2005, on SloohRadio.

If you’re new to Slooh, or just new to our NEO events, this article, discussing last week’s near-Earth event, explains what you can expect to see through the Slooh telescopes. You’ll also find many NEO images and animations in the Slooh User Forums. And if you have any questions or would like to meet some of your fellow Slooh members, visit us in the Slooh chatroom. You’ll find chatroom access buttons in the left-side menu of the Slooh Launchpad and in the bottom left corner of your Mission Interface.

It’s time for another Sky Safari and this time we’ll be touring the constellation Pegasus.

We see Pegasus in our sky on the edge of the Milky Way, so this constellation has its share of both near and far deep sky objects -  star clusters and nebulae, as well as distant galaxies and galaxy clusters.  Pegasus also has some important “firsts”, such as the first extrasolar planet to be discovered (near the star 51 Pegasi / aka  Bellerophon) and the first planetary nebula inside a globular cluster (Pease 1 in M51).

Pegasus, the winged horse, flies through our autumn skies.  Four bright stars arranged in a square about 15 degrees across (“the Great Square of Pegasus”) form the horse’s body.  The horse’s neck and head are a V-shaped string of stars on the western side of the square, starting from Markab (Alpha Pegasi) in the southwest corner.  Two strings of fainter stars, starting from Scheat (Beta Pegasi) in the northwest corner, form the horse’s forelegs.

Join us on Sunday night October 26 at 9 pm EDT (0100 UT on Monday morning) as we explore this constellation to learn more about its many treasures.

And, don’t forget your road map!

UPDATE: Sky Safari has been rescheduled to air on Sunday, November 2, at 7:25pm EDT / 00:25 UTC

Stephan’s Quintet in Pegasus:

WHAT: Near Earth Asteroid 2008 TT26

WHEN: October 20/21 and October 22/23

WHERE: Member Channel and SloohRadio

On October 23, 2008, NEO 2008 TT26 will pass less than four lunar distances from our planet, and we‘ll target the event with three Mission Alerts, featuring live missions through the Member Channel and SkyGuide commentary on SloohRadio.

On Monday night, at 21:00 UTC and 02:15 UTC (that’s 5pm EDT and 10:15pm EDT) we’ll observe the approach of this near-Earth asteroid; and then on Wednesday night at 00:30 UTC / 8:30pmEDT, we‘ll witness its actual near-Earth pass. That’s three different alerts, each featuring three back-to-back missions, for plenty of real-time imaging opportunity.

Through the Slooh telescopes, 2008 TT26 will probably appear as a multi-colored segmented line, not as the single star-like object that we often see with more distance asteroids like Ceres and Vesta. Its appearance will illustrate both its close proximity and its speed, with each color filter exposing the quickly moving object in a new location. While even the largest optical telescopes cannot reveal actual physical details of an object like 2008 TT26, it is Slooh’s real-time observations and what the images represent that make events like this such a unique and exciting Slooh experience.

At 49m - 110m (160ft - 360ft) 2008 TT26 is considered a small asteroid. Nonetheless, it is large enough to be potentially devastating in an impact. To compare, Arizona’s Barringer Meteorite Crater was created by a 46m (150ft) object. That impact resulted in a 20-40 ton megablast which produced winds in excess of 1,000km/hour, thermal emission burn damage extending out to 10km, and the scattering of more than 30 tons of iron debris over an eight-mile-wide area. Fifty-thousand years later, there remains a hole nearly one mile wide and 570 feet deep. An impact of this magnitude, today, would destroy a city.

At its closest point, 2008 TT26 will pass within a mere 3.6 LD of our planet. That’s about 860,000 miles or 1.4 million kilometers. Here on Earth, 860,000 miles is a tremendous distance; but in space, 860,000 miles is close enough to warrant legitimate concerns about future passes. Any number of scenarios could influence this near-Earth object’s trajectory and result in a more direct approach toward our planet.

Probably more disconcerting than its size and distance is the discovery date of 2008 TT26, which occurs just fourteen days before its predicted near-Earth pass. Such a timeline, especially with an object the size and distance of this asteroid, underscores the importance of various spaceguard endeavors. What if this object were on a more direct impact path? Would two weeks be enough time to prepare; and what exactly would we do? These are very legitimate, even urgent, questions when one considers Earth’s known impact history and the likelihood of future impacts.

2008 TT26 was discovered October 09 by LINEAR, one of several worldwide spaceguard projects around the globe. The LINEAR project utilizes a pair of Ground-based Electro-Optical Deep Space Surveillance (GEODSS) telescopes located at its Experimental Test Site in Sorocco, New Mexico. LINEAR is an MIT Lincoln Laboratory program and is funded by NASA and the USAF. The project’s stated mission is “to demonstrate the application of technology originally developed for the surveillance of Earth orbiting satellites, to the problem of detecting and cataloging near-Earth asteroids that threaten the Earth.” To date, LINEAR has discovered more than a quarter-million asteroids and over 2,000 near-Earth objects.

Mark your calendar to join one or all three of our Mission Alerts to watch as NEO 2008 TT26 makes its way past our planet next week. We’ll target it through the Slooh telescopes and talk more about it on SloohRadio. If you haven’t yet done so, be sure to visit the Slooh Chatroom. Events like this are much more fun when shared with fellow astronomers and enthusiasts.

For the first time in history, an incoming near-Earth object has been discovered and its impact point known before it reached our planet. Making this feat all the more significant is the object’s small 3m size. Three meters is remarkable. In fact, some would say serendipitous - not the large threat that survey programs seek to discover and yet so small as to underscore the remarkable capability of our “spaceguard” systems.

At the time of its discovery, this incoming object - catalogued as 2008 TC3 - was just 450,000km from our planet and approaching at 12km per second. With less than twenty-fours before “impact”, scientists had to quickly fine-tune trajectory calculations and immediately dispatch notices. And they did it with great success. The calculations were so precise, and the news dispersed so efficiently, that astronomers all across the world were able to track and even photograph the incoming object. More importantly, the information was shared and received responsibly - without inciting panic or prompting end-of-world discourse.

Serendipity turned to good fortune when it was learned that the entry event would occur in a nighttime sky. The object’s small size and likely stony composition meant that it would not survive passage through the Earth’s atmosphere; thus, it would be a sight-and-sound fireball event rather than an actual impact. Of course, fireball events are far more spectacular against a darkened sky. Pilots flying near the expected entry zone - over Northern Sudan, Africa, to be exact - were notified, and at least one pilot did report seeing a bright fireball. However, no actual fireball images are yet known, nor has anyone yet reported hearing the estimated 1.1-2.1 kiloton explosion.

Nonetheless, the approach images are as impressive as any fireball picture. Again, this was a 3-meter object discovered only hours before Earth-entry and traveling at tremendous speed. Photographing it posed a formidable challenge. But that challenge was met with equally striking results. Among the small handful of public images, Slooh achieved the only known non-scientific observatory images and, even more exciting, provided the only real-time observing and imaging opportunity to the non-scientific community.

Although there was little time to prepare, and not every mission was successful, Slooh members did witness the object’s approach just two hours before Earth entry, and a few images even reveal its track across the sky. Again, serendipity played some role. With such short notice, only two random mission slots remained open; and it was exactly those two missions that proved successful. Even those last unsuccessful missions, which had been quickly swapped out for a final attempt just minutes before impact, united the Slooh community in a common passion - that love of space-science and a desire to better understand our universe. Watching the live event provided a very unique opportunity, perhaps even a once-in-a-lifetime experience, for Slooh members.

NEO 2008 TC3 entered the Earth’s atmosphere October 7, at 0243 UTC. It was discovered barely 24-hours earlier, on Monday morning, October 6, by Richard Kowalski of the Catalina Sky Survey team. His discovery was made using Mt. Lemmon’s 60-inch Cassegrain reflector. The Catalina Sky Survey, a NASA-funded project and part of the University of Arizona’s Lunar and Planetary Laboratory, consists of three cooperating surveys utilizing facilities in both Australia and the United States, including the Mt. Lemmon telescope located just north of Tucson, Arizona. The survey is one of several worldwide working toward greater NEO discoveries and better PHA threat assessment.

In this Slooh FITS image, processed by TonyE, we see 2008 TC3’s path revealed as a multi-colored segmented line intersecting a bright background star. This image was acquired 2008Oct07, at 00:43 UTC, exactly 2 hours before entry.

How Do You Slooh? David Mekelburg, who joined Slooh in August of 2007, often uses the Slooh telescopes to image solar system objects - particularly asteroids. In his words, “Asteroids are interesting objects and a subject not well known by the amateur community. I like showing their movement in the sky, much better than a static image. I always google the object to obtain information on it’s history and current status. With spacecraft missions like Rosetta, we gain new insight on these curious objects.”

David, or DaveM as his fellow members know him, reserves time on the Slooh telescopes to take several images of a particular object across a coordinated timespan. He then compiles those images to create animations that illustrate the object’s movement across a background of stars. You may have seen some of his results in the Slooh Forum. Two recent examples include the planet Neptune with its most prominent moon Triton, and a Main Belt asteroid known as Kleopatra.

Last month, David imaged the near-Earth asteroid 1996 HW1 as it passed within 53 lunar distances of our planet:

He also recently imaged Vesta, our solar system’s brightest asteroid and one of the largest objects in the Main Asteroid Belt.

Asteroids and moons are not the only objects that David likes to image through the Slooh telescopes. He’s captured two notable comet events in less than three months, a planet trekking “across” a famous star cluster, and even a lunar eclipse.

In March, he imaged Comet 17P/Holmes sharing Dome 1’s wide-field view with the California Nebula:

Two months earlier, David heralded in the New Year with Comet 8P/Tuttle and Triangulum’s Pinwheel Galaxy:

In late spring, he recorded Mar’s path against a backdrop of the Beehive star cluster:

And in August, we had a lot of fun watching the partial lunar eclipse while David and others recorded the entire event:

If you’re new to Slooh and would like to try imaging transient objects, or if you’ve just never created animations but would like to learn more, David shares his sources. He uses JPL’s Horizon’s Web-Interface to generate coordinates for his missions; and he processes and animates his images using GIMP for Windows and a Gimp astronomy plug-in. David also suggests two Gimp animation tutorials for new users. The first guides you through creating simple animations, while the second is for more advanced users. You might also find Berkeley’s Gimp for Astronomers and the Faulkes-Telescope Project’s Astronomical Imaging tutorial helpful.

The most important thing to remember about using Slooh to track solar system objects, and creating animations with any program, is that its really not that difficult and you’ll find many Slooh members who are happy to assist, both in the Forum and in the Slooh Chatroom. And if you, too, enjoy creating animations with your Slooh images, we’d love to share your work here on the Slooh SkyLog.

If you’d like to see more of David’s Slooh images creations, check out his Animations page in the MySlooh members gallery.

And be sure to check back next month for another “How Do You Slooh?” We’ll  feature a member who targets multiple-star systems, share some of his remarkable images, and tell you how he does it.

NOTE: Each month, we feature a new member and the ways that he or she uses Slooh to explore the night sky. If you would like to share your Slooh experiences, send an email to tavi@slooh.com or tavianne@gmail.com, post a private message to TaviG. in the Slooh User Forums, or post a comment to any of the “How Do You Slooh?” features here on the Slooh SkyLog.

Of course, we are all familiar with the remarkable images that Slooh produces throughout the year, but did you know that you can use that imaging to explore the solar system, our own galaxy, and even the Universe?

How Do You Slooh? We want to know. Perhaps you are fond of planetary nebulae, the colorful expanding atmospheres of dying stars. Maybe you are working your way through a particular catalogue - Abell’s Galaxy Clusters, for example. Are you a comet-chaser,* intent on imaging even those faintest, most distant dirty snowballs?* Do you prefer the challenge of objects that are even closer to Earth, like our own man-made satellites* and the occasional near-Earth asteroid?

Whatever it is that you do with the Slooh telescopes, we want you to share your experiences, here, on the Slooh SkyLog. Each month, we’ll feature a new member or two, and share what they do and how they do it. Newer members can gain a little insight, more-experienced members who share the same interests can offer their own comments, and we can all ask questions to learn something new from each other.

If you’d like to share how you Slooh, send an email to tavi@slooh.com or tavianne@gmail.com, post a private message to me in the Slooh User Forums, or simply post a comment to any of the upcoming “How Do You Slooh?” features here on the Slooh SkyLog.

We’ll get started right away with a member who enjoys imaging transient objects - main belt asteroids and distant solar system moons. Be sure to stop back by tomorrow to see his latest work and to learn what tool he uses to even create animations with his Slooh images.

*NOTE: Comet 29/P by TonyF;   Comet 17/P by KathyC;   Satellites by SelbyR

Join us Saturday night, September 27th, for a Guided Missions Webcast with Slooh SkyGuide Marleen Bryan. We’ll watch celestial targets live through the Slooh telescopes as Marleen discusses the science and beauty behind each one through her video webcast; and if inclement weather closes the dome, we’ll proceed with a Virtual Slooh Tour.

Our live missions for the hour will focus primarily on various kinds of nebulae, including the famous dark “Horsehead” nebula, the “Crescent” emission nebula, and a beautiful supernova remnant commonly known as the “Veil” nebula. The show begins at 9pm EDT / 0100 UTC, rain or shine; so if you’re new to Slooh Webcasts, be sure to tune in early to get yourself set-up as needed.

Slooh webcasts are accessed, here, on the Slooh SkyLog - not through the Radio on the Mission Interface. You can hear and see your Slooh SkyGuide as you watch the missions simply by re-sizing your browser windows to fit side-by-side on your computer’s monitor. There is an example here. You can also visit the Slooh Chatroom for assistance.

AFTERSHOW NOTE: If you missed tonight’s live webcast, you can watch the recorded version, below. The presentation’s virtual missions, for your Slooh images reference, included NGC 7023 Iris Nebula, Sh2-155 Cave Nebula, Neptune, NGC 6818 Little Gem, IC 405 Flaming Star Nebula, M75 Globular Cluster, NGC 1535 Cleopatra’s Eye, Uranus, NGC 1365 Barred Spiral Galaxy, and M57 Ring Nebula.

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