Posted on by David Dickinson

Why This Weekend is Perfect for a Messier Marathon

To 'scopes, get set, marathon! (A homemade 14" Gregorian reflector, photo by author).

This coming weekend presents the first window for 2013 to complete a challenge in the realm of backyard astronomy and visual athletics. With some careful planning, persistence, and just plain luck, you can join the vaunted ranks of those seasoned observers who’ve seen all 110 objects in the Messier catalog… in one night.

Observing all of the objects in Messier’s catalog in a single night has become a bit of a sport over the last few decades for northern hemisphere observers, and several clubs and organizations now offer certificates for the same.  The catalog itself was a first attempt by French astronomer Charles Messier to catalog the menagerie of “faint fuzzies” strewn about the northern hemisphere sky.

Not that Charles knew much about the nature of what he was seeing. The modern Messier catalog includes a grab bag collection of galaxies, nebulae, open and globular clusters and more down to magnitude +11.5, all above declination -35°. Charles carried out his observations from Paris France at latitude +49° north. Unfortunately, this  also means that Messier catalog is the product of Charles Messier’s northern-based vantage point. The northernmost objects in the catalog are Messiers 81 & 82 at declination +69°, which never get above the horizon for observers south of latitude -21°. His initial publication of the catalog in 1774 contained 45 objects, and his final publication contained 103, with more objects added based on his notes after his death in 1817. (Fun fact: Messier is buried in the famous Père Lachaise Cemetery in Paris, site of other notable graves such as those of Chopin and Jim Morrison).

M51, the Whirlpool Galaxy, one of the more photogenic objects in the Messier catalog. (Credit: NASA/Hubble Heritage Project).
M51, the Whirlpool Galaxy, one of the more photogenic objects in the Messier catalog. (Credit: NASA/Hubble Heritage Project).

There’s a fair amount of controversy on Messier’s motivations and methods for compiling his catalog. The standard mantra that will probably always be with us is that Messier was frustrated with stumbling across these objects in his hunt for comets and decided to catalog them once and for all. He eventually discovered 13 comets in his lifetime, including Comet Lexell which passed only 2.2 million kilometres from Earth in 1770.

No one is certain where the modern tradition of the Messier Marathon arose, though it most likely had its roots in the amateur astronomy boom of the 1970s and was a fixture of many astronomy clubs by the 1980s. There are no Messier objects located between right ascension 21 hours 40 minutes  and 23 hours 20 minutes, and only one (M52)  between 23 hours 20 minutes and 0 hours 40 minutes. With the Sun reaching the “0 hour” equinoctial point on the March Vernal Equinox (falling on March 20th as reckoned in Universal Time for the next decade), all of the Messier objects are theoretically observable in one night around early March to early April. Taking into account for the New Moon nearest to the March equinox, the best dates for a weekend Messier marathon for the remainder of the decade are as follows;

Optimal Messier marathon dates for the remainder of the decade. (Compiled by author).
Optimal Messier marathon dates for the remainder of the decade. (Compiled by author).

Note that this year’s weekend is very nearly the earliest that it can occur. The optimal latitude for Messier marathoning is usually quoted as 25° north, about the latitude of Miami. It’s worth noting that 2013 is one of the very few years where the primary weekend falls on or before our shift one hour forward to Daylight Saving time, occurring this year on March 10th for North America.

Students of the Messier catalog will also know of the several controversies that exist within the list. For example, one wide double star in Ursa Major made its way into the catalog as Messier 40. There’s also been debate over the years as to the true identity of Messier 102, and most marathoners accept the galaxy NGC 5866 in its stead. Optics of the day weren’t the most stellar (bad pun intended) and this is evident in the inclusion of some objects but the omission of others. For example, it’s hard to imagine a would-be comet hunter mistaking the Pleiades (M45) for an icy interloper, but curiously, Messier omits the brilliant Double Cluster in Perseus.

M42, the Orion Nebula. (Photo by Author, taken back in the days of ye ole film!)
M42, the Orion Nebula. (Photo by Author, taken back in the days of ye ole film!)

It’s vital for Messier marathoners to run through objects in proper sequence. Most visual observers run these in groups, although Alex McConahay suggests in a recent April 2013 Sky & Telescope article that folks running a photographic marathon (see below) beware of wasting precious time crossing the celestial meridian (a maneuver which requires a telescope equipped with a German Equatorial mount to “flip” sides) hunting down objects. The unspoken “code of the skies” for visual Messier marathoners is that “Go-To” equipped scopes are forbidden. Part of the intended purpose of the exercise is to acquaint you with the night sky via star hopping to the target.

Most observers complete Messier objects in groups. You’ll want to nab M77 and M74 immediately after local dusk, or the marathon will be over before it starts. You’ll then want to move over to the Andromeda Galaxy and the collection of objects in its vicinity before scouring Orion and environs. From that point out, you can begin to slow down a bit and pace yourself through the galaxy groups in Coma Berenices and the Bowl of Virgo asterism. Another cluster of objects stretch out in the sky past midnight along the plane of our Milky Way Galaxy from Sagittarius to Cygnus, and the final (and often most troublesome) targets to bag are the Messier objects in Aquarius and M30 in Capricornus just before dawn. Remember, dark skies, warm clothes, and hot coffee are your friends in this endeavor!

There have been alternate rules or versions of Messier marathons over the years. Some imagers complete one-night photographic messier marathons. There are even abbreviated or expanded versions of the feat. It is also possible to nab most of the Messier catalog with a good pair of binoculars under clear skies. Probably the most challenging version we’ve heard of is sketching all 110 Messier objects in one evening… you might be forgiven for using a Go-To enabled telescope to accomplish this!

Finally, just like running marathons, the question we often get is why. Some may eschew transforming the art of dark sky observing into a task of visual gymnastics. We feel that to run through this most famous of catalogs in an evening is a great way to learn the sky and practice the fast-disappearing art of star hopping. And hey, no one’s saying you can’t take a year or three to finish the Messier catalog… its a big universe, and the New General Catalog (NGC) and Index Catalog (IC) containing thousands of objects will still be waiting. Have YOU seen all 110?

–      A perpetual listing of Messier marathon visibility by latitude by Tom Polakis.

–      An All Sky Map of the Messier catalog.

–      A handy priority list for a Messier marathon compiled by Don Machholz.

Posted on by David Dickinson

Spotting the Dragon: How to See SpaceX on Approach to the ISS This Weekend

Capture of the Dragon during the October 2012 CRS-1 mission. (Credit: NASA/ISS).

SpaceX’s Dragon spacecraft may be appearing in a backyard sky near you this weekend. Scheduled to launch this Friday on March 1st at 10:10 AM Eastern Standard Time (EST)/15:10 Universal Time (UT), this will be the 3rd resupply flight for the Dragon spacecraft to the International Space Station (ISS).  And the great news is, you may just be able to catch the spacecraft as it chases down the ISS worldwide.

The Space Shuttle and the ISS captured by the author as seen from Northern Maine shortly after undocking in June, 2007. 

Catching a satellite in low Earth orbit is an unforgettable sight. Satellites appear as moving “stars” against the background sky, shining steadily (unless they’re tumbling!) in the sunlight overhead in the dawn or dusk sky. Occasionally, you may catch a flare in brightness as a reflective panel catches the sunlight just right. The Hubble Space Telescope and the Iridium constellation of satellites can flare in this fashion.

At 109 metres in size, the ISS is the largest object ever constructed in orbit and is easily visible to the naked eye. It has an angular diameter of about 50” when directly overhead (about the visual size of Saturn plus rings near opposition). I can just make out a tiny box-like structure with binoculars when it passes overhead. If the orientation of the station and its solar panels is just right, it looks like a tiny luminous Star Wars TIE fighter as viewed through binoculars!

Dragon in the processing hangar at Cape Canaveral. (Credit: NASA/Kim Shiflett).
Dragon in the processing hangar at Cape Canaveral. (Credit: NASA/Kim Shiflett).

But what’s even more amazing is to watch a spacecraft rendezvous with the ISS, as diligent observers may witness this weekend. Your best bet will be to use predictions for ISS passes from your location. Heavens-Above, CALSky and Space Weather all have simple trackers for sky watchers. More advanced observers may want to use an application known as Orbitron which allows you to manually load updated Two-Line Element sets (TLEs) from Celestrak or NORAD’s Space-Track website for use in the field sans Internet connection. Note that Space-Track requires permission to access; they welcome amateur sat-spotters and educators, but they also want to assure that no “rogue entities” are accessing the site! Continue reading “Spotting the Dragon: How to See SpaceX on Approach to the ISS This Weekend”

Posted on by David Dickinson

Comet PANSTARRS: How to See it in March 2013

Comet 2011 L4 PanSTARRS imaged from Argentina by Luis Argerich on February 13th, 2013. (Credit: Luis Argerich - Nightscape photography. Used with Permission).

Great ready. After much anticipation, we could have the first naked eye comet of 2013 for northern hemisphere observers in early March. As discussed earlier this week on Universe Today, 2013 may well be the Year of the Comet, with two bright comets currently putting on a show in the southern hemisphere and comet C/2012 S1 ISON set to perform the closing cometary act of 2013. But while comet C/2012 F6 Lemmon won’t be visible for northern hemisphere residents until April, Comet C/2011 L4 PanSTARRS (which we’ll refer to simply as “Comet PanSTARRS” from here on out) may well become a fine early evening object in the first two weeks of March.

That is, if it performs. Comets are often like cats. Though we love posting pictures of them on the Internet, they often stubbornly refuse to perform up to our expectations. Some comets have been solid performers, like Hale-Bopp in 1997. Others are often promoted to great fanfare like Comet Kohoutek in 1973-74, only to fizzle and fade into notoriety.
Continue reading “Comet PANSTARRS: How to See it in March 2013”

Posted on by David Dickinson

In Search of Darkness: the Battle Against Light Pollution

Where the dark skies are (and aren't). NASA image in the Public Domain courtesy of Marc Imhoff, Craig Mayhem & Robert Simon (NASA/GSFC) Christopher Elvidge(NOAA).

A good majority of modern Americans have never seen truly dark skies. I was fortunate to grow up in northern Maine in the 1970s with skies dark enough to see the summer Milky Way right from my doorstep. For most of the Eastern Seaboard of the United States, this is no longer the case. During the blackout brought on by Hurricane Sandy over the tri-state area in 2012 and after Hurricane Andrew hit Miami in 1992, many urbanites got to see an unfamiliar sight first hand; a dark night sky. There were even calls to 9/11 reporting fires on the horizon, which were in fact the Milky Way!

Do your skies look like this? (Photo by Author).
Do your skies look like this?
(Photo by Author).

In just over two weeks time on March 10th, most of North America will “spring forward” once again to daylight savings time; three weeks afterwards on March 31st, the European Union will follow suit.

For astronomers, this means waiting until the later evening hours for total darkness and late start times for star parties. If it seems like we spend more of the year on daylight savings time, we in fact do; the Energy Policy Act of 2005 mandates that daylight savings for most of the U.S. (a majority of Arizona is a staunch hold out) now starts on the second Sunday of March and runs until the first Sunday of November, or about 65% of the year. But discussions of DST’s utility or anachronism aside, it puts just one more hurdle between astronomers and what they love: dark skies.

Does your observatories' night sky look like this? (Photo by Author).
Observatory versus light pollution. (Photo by Author).

You can’t even see your hand in front of your face under truly dark skies. Such darkness is measured on what’s known as the Bortle Scale, with 1 being dark enough to notice air glow and phenomena like the Gegenschein, while 9 is a washed out inner-city night sky, with perhaps only the Moon and the brightest planets punching through the haze.

We once did a Bortle scale estimation while waiting for an airport shuttle on the Las Vegas strip; Vegas is arguably the most light-polluted locale on the planet. Jupiter, the Moon and the brightest stars of Orion could only be seen if you knew exactly where to look for them. In contrast, we’ve heard many service members remark about how splendid the sky looks from such deployed locations as Afghanistan.

A vanishing treasure; true dark skies. (Photo by Author).
A vanishing treasure; true dark skies. (Photo by Author).

The encroachment of civilization on wilderness areas also means that most school star parties and downtown observatories are restricted to bright targets, and serious deep sky observers must now drive several hours for a reasonably dark sky. Living just outside the Tampa/Saint Petersburg area in Florida, I can actually tell if it’s cloudy or clear at night just by how bright our bedroom appears with lights out. A cloudy sky reflects all the city lights back down, creating a “false dawn” that fills the room.

Dark sky sites are like secret fishing holes for backyard astronomers. Everyone knows of a few, some of which are even carefully hidden and discussed in hushed tones for fear of the light generating hordes which will descend upon them.

For dark skies in the Tampa Bay area, most observers head north to Chiefland along the Nature Coast about a two hour drive north. If you’ve got boat access, a truly dark sky locale can be had in the Dry Tortugas off of the Florida Keys to the south.

Dark Skies at Dunham Farms, Georgia (Photo by Author).
Dark Skies at Dunham Farms, Georgia (Photo by Author).

We recently visited such a hidden “dark sky island” in northern Georgia. Dunham Farms is a great old farmhouse Bed & Breakfast in Liberty County near Hinesville, Georgia. Despite how close as it is to Savanna, Dunham Farms sits in a “triangle of darkness,” a rarity along the Atlantic coast. We estimated the sky at a Bortle Scale of 2-3 while we were there doing nighttime astrophotography. Astronomy clubs in nearby Savanna also find dark sky requiem at nearby Tybee Pier, and further north, clubs such as the Midlands Astronomers based out of Melton Observatory in Columbia, South Carolina head to nearby Congaree Swamp.

And so it is along much of the U.S. East Coast, as observers must make to pilgrimage ever further inland in search of dark skies. Truth is, much of nighttime lighting is simply wasted energy headed skyward to illuminate the undersides of clouds and aircraft. Not only does this destroy our pristine night sky, but it’s also a threat to nocturnal wildlife and humans as well. Nigh-time  lighting confuses migrating birds, often casuing them to fly into buildings.  In 2009 the American Medical Association joined the fight against light pollution, citing it as a health risk. Light pollution effects our natural circadian rhythms, and studies show it may be linked to increased cancer rates as well. Turns out, our bodies need darkness.

But there is light (bad pun intended) at the end of the tunnel. Light pollution ordinances are now on the books in many municipalities. In 2001, the International Dark Sky Association recognized Flagstaff, Arizona as the first dark sky certified city. Increasingly, observatories around cities in Arizona such as Tucson and Flagstaff are being recognized as national scientific assets to be safeguarded.

Of course, legislation on the books is only as good as its enforcement. There are no “light pollution police” on the beat, and ordinances against “light trespass” are only put into practice when someone complains about it. We’ve found that frequently, inviting the neighbors over for a “backyard star party” can avoid having them install a World War II surplus anti-aircraft spotlight in their back yard to begin with… hey, that’s what your security light looks like to us!

And there’s nothing stopping hardware outlets from selling light fixtures that are illegal to install. A good fixture directs light downward where it’s needed. Lowes has recently launched its line of dark sky compliant outdoor lighting, and hey, if enough customers “vote with their wallets” more may follow suit. Its money saved in these cash strapped times, and a night sky gained!

Posted on by Jason Major

A Parting Look at 2012 DA14: Was This a Warning Shot from Space?

Asteroid DA14 seen from the 2.1 Kitt Peak telescope as it departed the vicinity of Earth. Credit: NOAO/Nicholas Moskovitz (MIT)

Just as anticipated, on Friday, Feb. 15, asteroid 2012 DA14 passed us by, zipping 27,000 kilometers (17,000 miles) above Earth’s surface — well within the ring of geostationary weather and communications satellites that ring our world. Traveling a breakneck 28,100 km/hr (that’s nearly five miles a second!) the 50-meter space rock was a fast-moving target for professional and amateur observers alike. And even as it was heading away from Earth DA14 was captured on camera by a team led by MIT researcher Dr. Nicholas Moskovitz using the 2.1-meter telescope at the Kitt Peak National Observatory in Tucson, AZ. The team’s images are shown above as an animated gif (you may need to click the image to play it.)

This object’s close pass, coupled with the completely unexpected appearance of a remarkably large meteor in the skies over Chelyabinsk, Russia on the morning of the same day, highlight the need for continued research of near-Earth objects (NEOs) — since there are plenty more out there where these came from.

“Flybys like this, particularly for objects smaller than 2012 DA14, are not uncommon. This one was special because we knew about it well in advance so that observations could be planned to look at how asteroids are effected by the Earth’s gravity when they come so close.”

– Dr. Nicholas Moskovitz, MIT

The animation shows 2012 DA14 passing inside the Little Dipper, crossing an area about a third the size of the full Moon in 45 minutes. North is to the left.

(For a high-resolution version of the animation, click here.)

Exterior of the 2.1-meter telescope of the Kitt Peak National Observatory (NOAO)
Exterior of the 2.1-meter telescope of the Kitt Peak National Observatory (NOAO/AURA/NSF)

According to the National Optical Astronomy Observatory, which operates the Kitt Peak Observatory, Dr. Moskovitz’ NSF-supported team “are analyzing their data to measure any changes in the rotation rate of the asteroid after its close encounter with the Earth. Although asteroids are generally too small to resolve with optical telescopes, their irregular shape causes their brightness to change as they rotate. Measuring the rotation rate of the asteroid in this way allows the team to test models that predict how the earth’s gravity can affect close-passing asteroids. This will lead to a better understanding of whether objects like 2012 DA14 are rubble piles or single solid rocks.

“This is critical to understanding the potential hazards that other asteroids could pose if they collide with the Earth.”

So just how close was DA14’s “close pass?” Well, if Earth were just a few minutes farther along in its orbit, we would likely be looking at images of its impact rather than its departure.*

Although this particular asteroid isn’t expected to approach Earth so closely at any time in the foreseeable future — at least within the next 130 years — there are lots of such Earth-crossing objects within the inner Solar System… some we’re aware of, but many that we’re not. Identifying them and knowing as many details as possible about their orbits, shapes, and compositions is key.

Even this soon after the Feb. 15 flyby observations of 2012 DA14 have provided more information on its orbit and characteristics., allowing for fine-tuning of the data on it.

According to the Goldstone Radar Observatory web page, the details on 2012 DA14 are as follows:
Semimajor axis                   1.002 AU
Eccentricity                          0.108
Inclination                           10.4 deg
Perihelion distance           0.893 AU
Aphelion distance              1.110 AU
Absolute magnitude (H)   24.4
Diameter                               ~50 meters (+- a factor of two)
Rotation period                   ~6 h  (N. Moskovitz, pers. comm.)
Pole direction                      unknown
Lightcurve amplitude        ~1 mag  (N. Moskovitz, pers. comm.)
Spectral class                       Ld  (N. Moskovitz, pers. comm.)

Goldstone is currently conducting radar observations on the asteroid. A radar map of its surface and motion is anticipated in the near future.

Read more about Dr. Moskovitz’ observations on the NOAO website here, and see more images of 2012 DA14 captured by astronomers around the world in our previous article.

A bright meteor witnessed over Russia on Feb. 15, 2013 (RussiaToday)
A bright daytime meteor witnessed over Russia on Feb. 15, 2013 (RussiaToday)

Also, in an encouraging move by international leaders in the field, during the fiftieth session of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space, currently being held from at the United Nation Office in Vienna, near-Earth objects are on the agenda with a final report to be issued by an Action Team. Read the report PDF here.

*According to astronomer Phil Plait, while the orbits of Earth and DA14 might intersect at some point, on the 15th of February 2013 the asteroid slipped just outside of Earth’s orbit — a little over 17,000 miles shy. “It was traveling one way and the Earth another, so they could not have hit each other on this pass no matter where Earth was in its orbit,” he wrote in an email. Still, 17,000 miles is a very close call astronomically, and according to Neil deGrasse Tyson on Twitter, it “will one day hit us, like the one in Russian [sic] last night.” When? We don’t know yet. That’s why we must keep watching.

Posted on by David Dickinson

Jupiter and the Moon Have a Close Encounter in the Sky February 18, 2013

The January 2013 occultation of Jupiter by the Moon as seen from South America. (Image courtesy of Luis Argerich & Nightscape Photography; used with permission.

The movement of the Moon makes a fascinating study of celestial mechanics. Despite the light pollution it brings to the nighttime sky, we’re fortunate as a species to have a large solitary satellite to give us lessons in “Celestial Mechanics 101″

This weekend, we’ll get to follow that motion as the Moon crosses into the constellation Taurus for a near-pass of the planet Jupiter, and for a very few citizens of our fair world, occults it.

The Moon versus Jupiter during the previous occultation of the planet last month. (Image courtesy of Luis Argerich at Nightscape Photography; used with permission).
The Moon versus Jupiter during the previous occultation of the planet last month. (Image courtesy of Luis Argerich at Nightscape Photography; used with permission).

In astronomy, the term “occultation” simply means that one astronomical body passes in front of another. The term has its hoary roots in astronomy’s ancient past; just like the modern day science of chemistry sprung from the pseudo-science of alchemy, astronomy was once intertwined with the arcane practice of astrology, although the two have long since parted ways. When I use the term “occultation” around my non-space geek friends, (I do have a few!) I never fail to get a funny look, as if I just confirmed every wacky suspicion that they ever had about us backyard astronomers…

But those of us who follow lunar occultations never miss a chance to observe one. You’ll actually get to see the motion of the Moon as it moves against the background planet or star, covering it up abruptly. The Moon actually moves about 12° degrees across the sky per 24 hour period.

The position of the Moon & Jupiter as seen from Tampa (Feb 18th, 7PM EST), Perth, (Feb 18th 11:30UT) & London (Feb 18th at 19UT). Created by the author using Stellarium.
The position of the Moon & Jupiter as seen from Tampa (Feb 18th, 7PM EST), Perth, (Feb 18th 11:30UT) & London (Feb 18th at 19UT). Created by the author using Stellarium.

On the evening of Monday, February 18th, the 56% illuminated waxing gibbous Moon will occult Jupiter for Tasmania and southern Australia around 12:00 Universal Time (UT). Folks along the same longitude as Australia (i.e., eastern Asia) will see a close pass of the pair. For North America, we’ll see the Moon approach Jupiter and Aldebaran of February 17th (the night of the Virtual Star Party) and the Moon appear past the pair after dusk on the 18th.

Orientation of Jupiter, the Moon & Vesta on the evening of February 18th for North America. (Created by the author in Starry Night).
Orientation of Jupiter, the Moon & Vesta on the evening of February 18th for North America. (Created by the author in Starry Night).

But fret not; you may still be able to spot Jupiter near the Moon on the 18th… in the daytime. Daytime planet-spotting is a fun feat of visual athletics, and the daytime Moon always serves as a fine guide. Jupiter is juuuuuust bright enough to see near the Moon with the unaided eye if you know exactly where to look;

Jupiter captured during a close 2012 pass in the daytime! (Photo by author).
Jupiter captured during a close 2012 pass in the daytime! (Photo by author).

To see a planet in the daytime, you’ll need a clear, blue sky. One trick we’ve used is to take an empty paper towel tube and employ it as a “1x finder” to help find our target… binoculars may also help! To date, we’ve seen Venus, Jupiter, Sirius & Mars near favorable opposition all in the daylight… Mercury and Vega should also be possible under rare and favorable conditions.

This week’s occultation of Jupiter is the 3rd and final in a series that started in December of last year. The Moon won’t occult a planet again until an occultation of Venus on September 8th later this year, and won’t occult Jupiter again until July 9th, 2016. We’re also in the midst of a long series of occultations of the bright star Spica (Alpha Virginis) in 2013, as the Moon occults it once every lunation from somewhere in the world. Four major stars brighter than +1st magnitude lie along the Moon’s path near the ecliptic; Spica, Aldebaran, Regulus, and Antares which we caught an occultation of in 2009;

Also of note: we’re approaching a “plane-crossing” of the Jovian moons next year. This means that we’ll start seeing Callisto casting shadows on the Jovian cloud tops this summer on July 20th, and it will continue until July 21st, 2016. The orbits of the Jovian moons appear edge-on to us about every five years, and never really deviate a large amount. Callisto is the only moon that can “miss” casting a shadow on the disk of Jupiter in its passage.  The actual plane crossing as seen from the Earth occurs in November 2014. Jupiter reaches solar conjunction this year on June 19th and doesn’t come back into opposition until early next year on January 5th. 2013 is an “opposition-less” year for Jupiter, which occurs on average once per every 11-12 years. (One Jovian orbit equals 11.8 Earth years).

The Moon plus Jupiter during last month's close conjunction. (Photo by author).
The Moon plus Jupiter during last month’s close conjunction. (Photo by author).

But wait, there’s more… the Moon will also occult +7.7th magnitude 4 Vesta on February 18th at~21:00 UT. This occultation occurs across South America and the southern Atlantic Ocean. It would be fun to catch its ingress behind the dark limb of the Moon, and we bet that a precisely timed video might just show evidence for Vesta’s tiny angular diameter as it winks out. For North American observers, Vesta will sit just off the northern limb of the Moon… if you have never seen it, now is a great time to try!

Finally, we realized that also in the field with 4 Vesta is an explorer that just departed its environs, NASA’s Dawn spacecraft. Although unobservable from Earth, we thought that it would be an interesting exercise to see if it gets occulted by the Moon as well this week, and in fact it does, for a very tiny slice of the planet;

The occultation of the Dawn spacecraft as seen from Earth. Created by the author using Occult 4.0.
The occultation of the Dawn spacecraft as seen from Earth. Created by the author using Occult 4.0.

Hey, calculating astronomical oddities is what we do for fun… be sure to post those pics of Jupiter, the Moon and more up to our Universe Today Flickr page & enjoy the celestial show worldwide!

See more of Luis Argerich’s astrophotography at Nightscape Photography.

Graphics created by author using Stellarium, Starry Night and Occult 4.0 software.

Posted on by David Dickinson

Asteroid 2012 DA14: Observing Prospects and How to See It

2012-DA14
Image credit: NASA/JPL-CALTech

Mark your calendars: this Friday, February 15, 2013, is the close flyby of Near Earth Asteroid 2012 DA14, passing just 27,630 kilometers (17,168 miles) from the surface of the Earth. About 50 meters (164 feet) in size, 2012 DA14 and its close shave marks the the first time there has been passage of an asteroid this close that we’ve known a year beforehand. Yes, it passes within the ring of geosynchronous satellites girdling the Earth. No, there’s no danger, either to said satellites or the Earth, so Bruce Willis can stay home for this one.  But right behind those inquiries, the question we most frequently get is… how can I see it?

The orbital path of asteroid 2012 DA14 as seen face on (top) & near edge on (bottom). (Credit: JPL Small Body Database Browser).
The orbital path of asteroid 2012 DA14 as seen face on (top) & near edge on (bottom). (Credit: JPL Small Body Database Browser).

The great news is that an advanced observer can indeed catch 2012 DA14 on its close pass the night of February 15th… with a little skill and luck. Now for the bad news; the asteroid won’t be visible without binoculars or a telescope, and North America will largely miss out.

2012 DA14 will be really moving across the sky on closest approach, covering 0.8° per minute, or the diameter of a Full Moon every 45 seconds!  With its passage closer to the Earth than the ring of geosynchronous satellites, it’s worth treating the passage of the asteroid as a satellite and hunting it down accordingly. Catching and watching such a pass can be an unforgettable experience; not many objects in the sky show such swift motion in real time. In fact, 2012 DA14 will span the celestial sphere from declination -60° to +60° in just 4 hours!  Needless to say, its passage through the Earth’s gravity well will alter its orbit considerably; most planetarium software programs do not account for this and thus will introduce a large error for a heliocentric object. Compounding the dilemma is the large amount of parallactic shift of such a nearby object. As viewed from the span of the Earth, 2012 DA14 will have a parallax of ~20° at greatest approach!

The path of asteroid 2012 DA14 through the celestial sphere on February 15th. (Created by Author).
The path of asteroid 2012 DA14 through the celestial sphere on February 15th. (Created by Author).

But two sites on the web can help you with the search. One is Heavens-Above,  which currently has a link on its main page to custom generate sky charts for specific locations for 2012 DA14 (make sure you’re logged in as a registered user and your observing location is set correctly). Another option is to generate an ephemeris customized for your location from the JPL Solar System Dynamics Horizons Web-Interface.

Asteroid 2012 DA14 is approaching the planet Earth from “down under,” and moving almost exactly parallel to the 12 hour line in right ascension. In fact, it’ll cross very near the equinoctial point in Virgo (one of the two points where the celestial equator and the ecliptic cross) shortly after its closest approach on Friday, February 15th at 19:25UT. The asteroid will be at the local zenith (straight overhead) for observers in the pre-dawn hours located in western Indonesia at closest approach. Australia and eastern Asia will have a shot at seeing the asteroid as it whizzes through the sky in the early morning hours of February 16th local. Observers in western Asia, Africa and Europe will see the asteroid lower to the east on the night of the 15th. Note that 2012 DA14 juuuuuust misses Earth’s shadow (see strip chart) at closest approach. The shadow of our fair planet is ~20° across at the distance of the geosynchronous satellites; had it passed about a month later, we would have seen an “asteroid eclipse!” In fact, “eclipse season” for geosynchronous satellites occurs right around the equinoxes and is only a month away.

The “banana strip chart” shows the path of 2012 DA14 from the time it reaches a magnitude brighter than +10 at 17:40UT until it dips back down below it at 22:10UT on the same night. It also shows the width of uncertainty for its position due to the aforementioned 20° of parallax, and the points that it enters and departs the distance sphere of the geosynchronous satellites. Keep in mind, these satellites still orbit roughly hundred times higher than the International Space Station!

A good search strategy to catch 2012 DA14 is to actually to treat it like you’re hunting for a faint satellite. Find the time that it’s crossing a set declination and begin scanning with binoculars in right ascension back and forth until you “ambush” your astronomical prey moving slowly against the starry background. If using a telescope, use the lowest power and widest field of view that the instrument will allow. We’ve used this technique in the past to sweep up Near Earth Asteroids 2005 YU55 and 99942 Apophis and routinely use it to hunt for satellites fainter than naked eye visibility. At closest approach, asteroid 2012 DA14 will shine at around +8th magnitude as it crosses the Bowl of Virgo northward past Denebola in the constellation Leo.

Recent measurements early this month conducted by astronomers at the Las Campanas observatory in Chile refined the orbit of 2012 DA14, placing its February 15th passage just 45 kilometres closer to Earth than previously calculated but still well outside the threat zone. Campaigns are underway to refine measurements of its orbit even further on this pass. We won’t get another close pass of 2012 DA14 until February 16th, 2046 when the asteroid misses us at about twice the distance of the Moon. An impact has been ruled out for this century. Predictions get less certain the further you project them into time, and 2012 DA14 will definitely be a space rock worth keeping tabs on!     

Posted on by David Dickinson

Mercury’s False Moon: The Mercury/Mars Planetary Conjunction this Weekend

Mercury and Mars on February 8, 2013. See how close they'll be? Image credit: Stellarium.

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The history of astronomy is littered with astronomical objects in the solar system that have fallen to the wayside. These include fleeting sightings of Venusian moons, inter-mercurial planets, and even secondary moons of the Earth.

While none of these observations ever amounted to true discoveries, this weekend gives observers and astrophotographers a unique chance to “mimic” a spurious discovery that has dotted astronomical lore: a visual “pseudo-moon” for the planet Mercury. This “moon illusion” will occur on February 8, 2013 during the closest conjunction of two naked eye planets in 2013. February offers a chance to see the fleeting Mercury in the sky, and this conjunction with Mars will provide the opportunity to see how Mercury would look in the night sky if it had a moon!

Mercury has been suspected of having moons before. On March 29th 1974, the Mariner 10 spacecraft became the first mission to image the innermost world up close. Mariner 10 mapped 40-45% of Mercury on 3 successive passes, revealing a pock-marked world not that different than our own Moon. But Mariner 10 also detected something more: brief anomalies in the ultra-violet spectrum suggestive of a moon with a 3 day period. For a very brief time, Mercury was thought to have a moon of its own, and NASA nearly made a press release to this effect. The spectroscopic binary 31 Crateris is now suspect in the anomalous readings. Still, the Mariner 10 observation made researchers realize the observations in the extreme UV were possible over interstellar distances.

The planet Mercury as seen by NASA's Messenger spacecraft (Credit: NASA/JPL).
The planet Mercury as seen by NASA's MESSENGER spacecraft (Credit: NASA/JHUAPL).

Today, NASA has a permanent emissary orbiting Mercury with its MESSENGER spacecraft. MESSENGER first entered orbit around Mercury on March 18th, 2011 after a series of trajectory changing flybys. MESSENGER has filled in the map of the remainder of Mercury’s surface, with no signs of the anomalous “moon.” Interestingly, MESSENGER was also on the lookout for “Vulcanoids” (tiny asteroids interior to Mercury’s orbit; sorry, Mr. Spock) while enroute to its final orbital insertion. NASA even released an April Fool’s Day prank of a fake “discovery” of a Mercurial moon dubbed Caduceus in 2012.

But MESSENGER has made some fascinating true to life discoveries, such as sampling Mercury’s tenuous exosphere & the possibility of ice at its permanently shadowed poles. Lots of new features have been mapped and named on Mercury, following the convention of naming features after famous deceased artists, musicians and authors set forth by the International Astronomical Union. It’s amazing to think that we had no detailed views at the entire surface of Mercury until the 1970’s, although some ground-based professional observatories and even skilled amateurs are now doing just that.

Fast forward to this weekend. Mercury is just beginning its first apparition of six in 2013 this week and is currently visible low in the dusk sky after sunset to the west. Mercury reaches greatest eastern elongation on February 16th at 18.1° from the Sun. Interestingly, that’s very close to the shortest elongation that can occur. Mercury’s orbit is eccentric enough that greatest elongation as seen from the Earth can vary from 17.9° to 27.8°. This month’s elongation happens within only 5 hours of Mercury reaching perihelion at 46 million kilometers from the Sun. This means that Mercury won’t peak above the dusk horizon for mid-northern latitude observers quite as high as it will during the next evening apparition of the planet in June.

Mercury Mars
caption =”Looking west 30 minutes after sunset on Feb. 8th from latitude 30° north.

 

This appearance of Mercury does, however, have some things going for it. First off, the ecliptic sits at a favorable viewing angle, roughly perpendicular to the western horizon at dusk for mid- to high northern latitude observers. This gives Mercury a bit of a “boost” out of the weeds. Secondly, Mercury is a full magnitude (2.512 times) brighter when it reaches maximum elongation near perihelion than aphelion, such as its next appearance in the dawn sky on March 31st of this year. Mercury will reach magnitude -0.5, versus +0.5 in late March.

To see Mercury, find a site with a western horizon free of ground clutter and start sweeping the horizon with binoculars about 15 minutes after local sunset. See a reddish dot just above Mercury? That’s the planet Mars, shining about 7 times fainter than -1.0 magnitude Mercury at magnitude +1.2. Mercury is fast approaching a conjunction with Mars; the two will be only 15’ apart (half the average width of a Full Moon) on the evening of February 8th at 17:00 Universal Time!

If you ever wondered how Mercury would appear with a moon, now is a good time to take a look! Again, binoculars are the best optical tool for the job. Can you see both with the naked eye? Can you place both in the same low power field of view with a telescope? You’ll only have a 15-30 minute window (depending on latitude) to snare the pairing before they follow the setting Sun below the horizon. Photographing the pair will be tricky, though not impossible, as they present a very low contrast against the bright background twilight sky.

Cass_Obs_13_Feb_5_6
caption =”Mercury (lower center) & Mars (upper center) imaged by Mike Weasner on February 5th.

 

Don’t expect to see detail on Mercury or Mars telescopically; Mercury only appears 5.8” across on the 8th, while Mars is 4” in apparent size. Mars disappears from view later this month to reach solar conjunction on April 18th 2013. The waxing crescent Moon just 1 day after New joins the pair on the evenings of February 10th and 11th.

Now for the “Wow” factor of what you’re seeing. The conjunction of Mars and Mercury only appears close; in reality, they are over 180 million kilometers apart. Mercury is 1.15 Astronomical Units (A.U.s)/178 million kilometers from us on February 8th, while Mars is nearly at its farthest from us at 2.31 A.U.s/358 million kilometers distant. It’s splendid to think that with Curiosity and friends operating on Mars and Messenger orbiting Mercury, we now have permanent robotic “eyes” on and around both!

Credits: Simulation created by the author using Starry Night.

Mercury & Mars courtesy of Mike Weasner and the Cassiopeia Observatory. Used with permission.

Posted on by Ken Kremer

Deep Impact Images Spectacular incoming Comet ISON – Curiosity & NASA Armada Will Try

Image Caption: This image of comet ISON (C/2012 S1) ) from NASA’s Deep Impact spacecraft clearly shows the coma and nucleus on Jan. 17/18, 2013 beyond the orbit of Jupiter. See the dramatic new movie sequence below. It combines all 146 80-second clear filter exposures for a total integration time of 11680 seconds (about 3.25 hours). Individual frames were shifted to align the comet at the center before coadding. By keeping the comet centered and adding all of the images together, the stars effectively get smeared so the long streaks are the trails of background stars. Some have called it the “Comet of the Century.” Credit: NASA

NASA’s legendary Deep Impact comet smashing spacecraft has just scored another major coup – Imaging the newly discovered Comet ISON. The comet could possibly become one of the brightest comets ever late this year as it passes through the inner Solar System and swings around the Sun for the very first time in history – loaded with pristine, volatile material just raring to burst violently forth from the eerie surface, and is therefore extremely interesting to scientists. See the Movie below

“Comet ISON was just imaged by Deep Impact out by Jupiter on Jan. 17 and 18,” said Dr. Jim Green, Director of NASA Planetary Sciences at NASA HQ, in an exclusive interview with Universe Today on the campus of Princeton University. “We will try to look at ISON with the Curiosity rover as it flies past Mars, and with other NASA assets in space [along the way]. It should be spectacular!”

“We are all, ops team and science team, thrilled that we were able to make these observations when the comet was still more than 5 AU from the sun,” said Deep Impact Principal Investigator Prof. Michael A’Hearn of the University of Maryland, in an exclusive interview with Universe Today.

ISON could potentially become the next “Great Comet”, according to NASA. Deep Impact is the first spacecraft to observe ISON.

“We are continuing to observe ISON – it is observable from Deep Impact into mid-March 2013,” A’Hearn told me.

ISON will be the 4th comet observed by Deep Impact. On July 4, 2005 the spacecraft conducted a close flyby of Comet Tempel 1 and delivered a comet smashing impactor that made headlines worldwide. Next, it flew near Hartley 2 in Nov. 2010. In January 2012, the spacecraft performed a long distance imaging campaign on comet C/2009 P1 (Garradd). And it has enough fuel remaining for an Asteroid encounter slated for 2020 !

“NASA’s assets at Mars should be able to observe ISON because it will fly really, really close to Mars!” Green said with a big smile – and me too, as he showed me a sneak preview of the brand new Deep Impact movie.

“ISON observations are in the cue for Curiosity from Mars surface and from orbit with NASA’s Mars Reconnaissance Orbiter (MRO) – and we’ll see how it works out. It should be pretty spectacular. We will absolutely try with Curiosity’s high resolution Mastcam 100 camera.”

“LRO (NASA’s Lunar Reconnaissance Orbiter) also has a good shot at ISON.”

“Because of the possibility of observations of for example ISON, with probes like Deep Impact is why we want to keep NASA’s [older] assets viable.”

146 visible light images snapped by Deep Impact just days ago on Jan. 17 and 18, have been compiled into a dramatic video showing ISON speeding through interplanetary space back dropped by distant star fields – see above and below. The new images were taken by the probes Medium-Resolution Imager (MRI) over a 36-hour period from a distance of 493 million miles (793 million kilometers).

“A composite image, combining all of the Jan 17/18 data – after cleaning up the cosmic rays and improving the S/N (signal to noise ratio) clearly shows the comet has a coma and tail,” said Tony Farnham, a Deep Impact research scientist at the University of Maryland, to Universe Today.

Video Caption: This series of images of comet C/2012 S1 (ISON) was taken by the Medium-Resolution Imager (MRI) of NASA’s Deep Impact spacecraft over a 36-hour period on Jan. 17 and 18, 2013. At the time, the spacecraft was 493 million miles (793 million kilometers) from the comet. Credit: NASA/JPL-Caltech/UMD

ISON is a conglomeration of ice and dust and a long period, sun-grazing comet.

“It is coming in from the Solar System’s Oort cloud at the edge of the Solar System”, said Green, and was likely disturbed out of its established orbit by a passing star or other gravitational effects stemming from the Milky Way galaxy. “It will pass within 2.2 solar radii during perihelion and the Sun will either blast it apart or it will survive.”

Despite still being in the outer Solar System and a long distance from the Sun, ISON is already quite “variable” said A’Hearn, and it’s actively spewing material and ‘outgassing”.

The tail extending from the nucleus was already more than 40,000 miles (64,400 kilometers) long on Jan. 18. It’s a science mystery as to why and the Deep Impact team aims to try and determine why.

In addition to imaging, Deep Impact will also begin collecting long range spectral observations in the next week or so to help answer key questions.

“In mid-February, the solar elongation will allow IR (infrared) spectra for a few weeks,” A’Hearn elaborated.

“The 6-7% variability that we observed in the first day of observing shows that there is variable ‘outgassing’, presumably modulated by rotation of the nucleus. We hope to pin down the rotational period with the continuing images.”

“The interesting question is what drives the outgassing!”

Since ISON is still a very great distance away at more than 5 AU, data collection will not be an easy task. The comet is 5.1 AU from the Sun and 5.3 AU from Deep Impact. And the mission could also be imperiled by looming slashes to NASA’s budget if the Federal sequester actually happens in March.

“Getting spectra will be a real challenge because, at these large heliocentric and geocentric distances, the comet is really faint. However, maybe we can test whether CO2 is driving the outgassing,” Ahearn explained.

“Since we have the only facility capable of measuring CO2, it will be important to observe again in our second window in July-August, but that depends on NASA finding a little more money for us.”

“We, both the ops team and the science team, are funded only for the observations through March,” A’Hearn stated.

Although observing predictions for the brightness of comets are sometimes notoriously wrong and they can fade away precipitously, there is some well founded hope that ISON could put on a spectacular sky show for observers in both the northern and southern hemispheres.

The comet will continue to expand in size and grow in brightness as it journeys inward.

“ISON might be pretty spectacular,” said Green. “If things work out it might become bright enough to see during the day and be brighter than the Moon. The tail might be 90 degrees.”

comet20130205-full

Image caption: This is the orbital trajectory of comet C/2012 S1 (ISON). The comet is currently located just inside the orbit of Jupiter. In November 2013, ISON will pass less than 1.1 million miles (1.8 million kilometers) from the sun’s surface. The fierce heating it experiences during this close approach to the sun could turn the comet into a bright naked-eye object. Credit: NASA/JPL-Caltech

The best times to observe the comets head and growing tail will be from Nov. 2013 to Jan. 2014, if it survives its closest approach to the Sun, known as perihelion, on Nov. 28, 2013 and doesn’t break apart.

There’s no need to worry about doomsday predictions from conspiracy theorists. At its closest approach next Christmas season on Dec. 26, 2013, ISON will pass by Earth at a safe distance of some 40 million miles.

A pair of Russian astronomers only recently discovered the comet on Sept. 21, 2012, using the International Scientific Optical Network’s 16-inch (40-centimeter) telescope near Kislovodsk.

The study of comets has very important implications for understanding the evolution of not just the Solar System but also the origin of life on Earth. Comets delivered a significant portion of the early Earth’s water as well as a range of both simple and complex organic molecules – the building blocks of life.

Ken Kremer

HRI_937_1[1]

Image caption. Deep Impact images Comet Tempel 1 alive with light after colliding with the impactor spacecraft on July 4, 2005. CREDIT: NASA/JPL-Caltech/UMD

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: December 3-9, 2012



NGC 457 Courtesy of Ken and Emilie Siarkiewicz/Adam Block/NOAO/AURA/NSF

Greetings, fellow SkyWatchers! With a whole lot less Moon present in the early evenings, it’s time to do some very different studies – from North to South! We’ll be having a look at planetary nebulae, globular clusters, galactic star clusters and some great galaxies, too! Need more? Then SH viewers can kick back and relax to a meteor shower, too! Whenever you’re ready, just meet me in the back yard…

Monday, December 3 – Today in 1971, the Soviet Mars 3 became the first spacecraft to make a soft landing on the red planet, and two years later on this same date the Pioneer 10 mission became the first spacecraft to fly by Jupiter. One year later on this same date? Pioneer 11 did the same thing!

Tonight let’s familiarize ourselves with the vague constellation of Fornax. Its three brightest stars form a shallow V just south of the Cetus/Eridanus border and span less than a handwidth of sky. Although it’s on the low side for northern observers, there is a wealth of sky objects in this area.

Try having a look at the easternmost star – 40-light-year distant Alpha. At magnitude 4, it is not easy, but what you’ll find there is quite beautiful. For binoculars, you’ll see a delightful cluster of stars around this long-term binary – but telescopes will enjoy it as a great golden double star! First measured by John Herschel in 1835, the distance between the pair has narrowed and widened over the last 172 years and it is suspected its orbital period may be 314 years. While the 7th magnitude secondary can be spotted with a small scope – watch out – because it may also be a variable which drops by as much as a full magnitude!

Tuesday, December 4 – Today in 1978, the Pioneer/Venus Orbiter became the first spacecraft to orbit Venus. And in 1996, the Mars Pathfinder mission was launched!

For larger telescopes, set sail for Beta Fornacis tonight and head 3 degrees southwest (RA 02 39 42.5 Dec -34 16 08.0) for a real curiosity – NGC 1049.

At magnitude 13, this globular cluster is a challenge for even large scopes – and with good reason. It isn’t in our galaxy. This globular cluster is a member of the Fornax Dwarf Galaxy – a one degree span that’s so large it was difficult to recognize as extra-galactic – or at least it was until the great Harlow Shapely figured it out! NGC 1049 was first discovered and cataloged by John Herschel in 1847, only to be reclassified as “Hodge 3″ in a 1961 study of the system’s five globular clusters by Paul Hodge. Since that time, yet another globular has been discovered! Good luck…

Wednesday, December 5 – How about something a little more suited to the mid-sized scope tonight? Set your sights on Alpha Fornacis and let’s head about 3 fingerwidths northeast (RA 03 33 14.65 Dec -25 52 18.0) for NGC 1360.

In a 6? telescope, you’ll find the 11th magnitude central spectroscopic double star of this planetary nebula to be very easy – but be sure to avert because the nebula itself is very elongated. Like most of my favorite things, this planetary is a rule-breaker since it doesn’t have an obvious shell structure. But why? Rather than believe it is not a true planetary by nature, studies have shown that it could quite possibly be a very highly evolved one – an evolution which has allowed its gases to begin to mix with the interstellar medium. Although faint and diffuse for northern observers, those in the south will recognize this as Bennett 15!

Tonight let’s take advantage of early dark and venture further into Cassiopeia. Returning to Gamma, we will move towards the southeast and identify Delta. Also known as Ruchbah, this long-term and very slight variable star is about 45 light-years away, but we are going to use it as our marker as we head just one degree northeast and discover M103. As the last object in the original Messier catalog, M103 (NGC 581) was actually credited to Mechain in 1781. Easily spotted in binoculars and small scopes, this rich open cluster is around magnitude 7, making it a prime study object. At about 8000 light-years away and spanning approximately 15 light-years, M103 offers up superb views in a variety of magnitudes and colors, with a notable red in the south and a pleasing yellow and blue double to the northwest.

Viewers with telescopes and larger binoculars are encouraged to move about a degree and half east of M103 to view a small and challenging chain of open clusters, NGCs 654 (Right Ascension: 1 : 44.1 – Declination: +61 : 53), 663 and 659! Surprisingly larger than M103, NGC 663 (Right Ascension: 1:46.0 – Declination: +61:15) is a lovely fan-shaped concentration of stars with about 15 or so members that resolve easily to smaller aperture. For the telescope, head north for NGC 654, (difficult, but not impossible to even a 114mm scope) which has a bright star on its southern border. South of NGC 663 is NGC 659 (Right Ascension: 1 : 44.2 – Declination: +60 : 42) which is definitely a challenge for small scopes, but its presence will be revealed just northeast of two conspicuous stars in the field of view.

Thursday, December 6 – For northern observers clamoring for brighter stellar action, look no further tonight than the incredible “Double Cluster” about four fingerwidths southeast of Delta Cassiopeiae (Right Ascension: 2 : 22.4 – Declination: +57 : 07). At a dark sky site, this incredible pair is easily located visually and stunning in any size binoculars and telescopes. As part of the constellation of Perseus, this double delight is around 7000 light-years away and less than 100 light-years separates the pair. While open clusters in this area are not really a rarity, what makes the “Double Cluster” so inviting is the large amount of bright stars within each of them. Well known since the very beginnings of astronomy, take the time to have a close look at both Chi (NGC 884) and H Persei very carefully. Note how many colorful stars you see, and the vast array of double, multiple and variable systems!

Now, let’s return again to Cassiopeia and start at the central-most bright star, Gamma. Four degrees southeast is our marker for this starhop, Phi Cassiopeiae. By aiming binoculars or telescopes at this star, it is very easy to locate an interesting open cluster, NGC 457 (Right Ascension: 1 : 19.1 – Declination: +58:20), because they will be in the same field of view.

This bright and splendid galactic cluster has received a variety of names over the years because of its uncanny resemblance to a figure. Some call it an “Angel,” others see it as the “Zuni Thunderbird;” I’ve heard it called the “Owl” and the “Dragonfly,” but perhaps my favorite is the “E.T. Cluster,” As you view it, you can see why! Bright Phi and HD 7902 appear like “eyes” in the dark and the dozens of stars that make up the “body” appear like outstretched “arms” or “wings.” (For E.T. fans? Check out the red “heart” in the center.)

All this is very fanciful, but what is NGC 457, really? Both Phi and HD 7902 may not be true members of the cluster. If 5th magnitude Phi were actually part of this grouping, it would have to have a distance of approximately 9300 light-years, making it the most luminous star in the sky, far outshining even Rigel! To get a rough idea of what that means, if we were to view our own Sun from this far away, it would be no more than magnitude 17.5. The fainter members of NGC 457 comprise a relatively young star cluster that spans about 30 light-years. Most of the stars are only about 10 million years old, yet there is an 8.6 magnitude red supergiant in the center. No matter what you call it, NGC 457 is an entertaining and bright cluster that you will find yourself returning to again and again. Enjoy!

Friday, December 7 – Today is the birthday of Gerard Kuiper. Born 1905, Kuiper was a Dutch-born American planetary scientist who discovered moons of both Uranus and Neptune. He was the first to know that Titan had an atmosphere, and he studied the origins of comets and the solar system.

Tonight let’s honor his achievements as we have a look at another bright open cluster known by many names: Herschel VII.32, Melotte 12, Collinder 23, and NGC 752. You’ll find it three fingerwidths south (RA 01 57.8 Dec +37 41) of Gamma Andromedae…

Under dark skies, this 5.7 magnitude cluster can just be spotted with the unaided eye, is revealed in the smallest of binoculars, and can be completely resolved with a telescope. Chances are it was first discovered by Hodierna over 350 years ago, but it was not cataloged until Sir William gave it a designation in 1786. But give credit where credit is due… For it was Caroline Herschel who observed it on September 28, 1783! Containing literally scores of stars, galactic cluster NGC 752 could be well over a billion years old, strung out in chains and knots in an X pattern of a rich field. Take a close look at the southern edge for orange star 56: while it is a true binary star, the companion you see is merely optical. Enjoy this unsung symphony of stars tonight!

Now, let’s go back to Cassiopeia. Remembering Alpha’s position as the westernmost star, go there with your finderscope or binoculars and locate bright Sigma and Rho (each has a dimmer companion). They will appear to the southwest of Alpha. It is between these two stars that you will find NGC 7789 (RA 23 57 24.00 Dec +56 42 30.0).

Absolutely one of the finest of rich galactic opens bordering on a loose globular, NGC 7789 has a population of about 1000 stars and spans a mind-boggling 40 light-years. At well over a billion years old, the stars in this 5000 light-year distant galactic cluster have already evolved into red-giants or super-giants. Discovered by Caroline Herschel in the 18th century, this huge cloud of stars has an average magnitude of 10, making it a great large binocular object, a superb small telescope target, and a total fantasy of resolution for larger instruments.

Saturday, December 8 – Today in history (1908) marks “first light” for the 60? Hale Telescope at Mt. Wilson Observatory. Not only was it the largest telescope of the time, but it ended up being one of the most productive of all. Almost 100 years later, the 60? Hale is still in service as a public outreach instrument. If we could use the 60? tonight to study, where would we go? My choice would be the Fornax Galaxy Cluster!

Containing around 20 galaxies brighter than 13th magnitude in a one degree field, here is where a galaxy hunter’s paradise begins! About a degree and a half north of Tau Fornacis is the large, bright and round spiral NGC 1398 (Right Ascension: 3 : 38.9 – Declination: -26 : 20). A little more than a degree west-northwest is the easy ring of the planetary nebula NGC 1360. Look for the concentrated core and dark dustlane of NGC 1371 a degree north-northeast – or the round NGC 1385 which accompanies it. Why not visit Bennett 10 or Caldwell 67 as we take a look at NGC 1097 (Right Ascension: 2:46.3 – Declination: -30:17) about 6 degrees west-southwest of Alpha? This one is bright enough to be caught with binoculars!

Telescopes will love NGC 1365 (Right Ascension: 3:33.6 – Declination: -36:08) at the heart of the cluster proper. This great barred spiral gives an awesome view in even the smallest of scopes. As you slide north, you will encounter a host of galaxies, NGCs 1386, 1389, 1404, 1387, 1399, 1379, 1374, 1381 and 1380. There are galaxies everywhere! But, if you lose track? Remember the brightest of these are two ellipticals – 1399 and 1404. Have fun!

Now, let’s haunt Cassiopeia one last time – with studies for the seasoned observer. Our first challenge of the evening will be to return to Gamma where we will locate two patches of nebulosity in the same field of view. IC 59 and IC 63 are challenging because of the bright influence of the star, but by moving the star to the edge of the field of view you may be able to locate these two splendid small nebulae. If you do not have success with this pair, why not move on to Alpha? About one and a half degrees due east, you will find a small collection of finderscope stars that mark the area of NGC 281 (RA 00 52 25.10 Dec +56 33 54.0). This distinctive cloud of stars and ghostly nebulae make this NGC object a fine challenge!

The last things we will study are two small elliptical galaxies that are achievable in mid-sized scopes. Locate Omicron Cassiopeiae about 7 degrees north of M31 and relocate our earlier study, a galactic pair that is associated with the Andromeda group – NGC 185 (RA 00 38 57.40 Dec +48 20 14.4) and NGC 147 (RA 00 33 11.79 Dec +48 30 24.8). The constellation of Cassiopeia contains many, many more fine star clusters, and nebulae – and even more galaxies. For the casual observer, simply tracing over the rich star fields with binoculars is a true pleasure, for there are many bright asterisms best enjoyed at low power. Scopists will return to “rock with the Queen” year after year for its many challenging treasures. Enjoy it tonight!

Sunday, December 9 – Southern Hemisphere viewers, you’re in luck! This is the maximum of the Puppid-Velid meteor shower. With an average fall rate of about 10 per hour, this particular meteor shower could also be visible to those far enough south to see the constellation of Puppis. Very little is known about this shower except that the streams and radiants are very tightly bound together. Since studies of the Puppid-Velids are just beginning, why not take the opportunity to watch? Viewing will be possible all night long and although most of the meteors are faint, this one is known to produce an occasional fireball.

Since we’re favoring the south tonight, let’s set northern observers toward a galaxy cluster – Abell 347 – located almost directly between Gamma Andromedae and M34. Here you will find a grouping of at least a dozen galaxies that can be fitted into a wide field view. Let’s tour a few…

The brightest and largest is NGC 910 (Right Ascension: 2 : 25.4 – Declination: +41:50), a round elliptical with a concentrated nucleus. To the northwest you can catch faint, edge-on NGC 898. NGC 912 is northeast of NGC 910, and you’ll find it quite faint and very small. NGC 911 to the north is slightly brighter, rounder, and has a substantial core region. NGC 909 further north is fainter, yet similar in appearance. Fainter yet is more northern NGC 906, which shows as nothing more than a round contrast change. Northeast is NGC 914, which appears almost as a stellar point with a very small haze around it. To the southeast is NGC 923 which is just barely visible with wide aversion as a round contrast change. Enjoy this Abell quest!

And the countdown is on… Enjoy these last few weeks of the SkyWatcher, cuz’ the old woman is going to retire at the end of this year! Until then? Clear skies!