Skywatching Archives

May 20, 2015December 23, 2015 by David Dickinson

Hunting LightSail in Orbit

The hunt is on in the satellite tracking community, as the U.S. Air Force’s super-secret X-37B space plane rocketed into orbit today atop an Atlas V rocket out of Cape Canaveral. This marks the start of OTV-4, the X-37B’s fourth trip into low Earth orbit. And though NORAD won’t be publishing the orbital elements for the mission, it is sure to provide an interesting hunt for backyard satellite sleuths on the ground.

Previous OTV missions were placed in a 40 to 43.5 degree inclination orbit, and the current NOTAMs cite a 61 degree azimuth angle for today’s launch out of the Cape which suggests a slightly shallower 39 degree orbit. Such variability speaks to the versatile nature of the second stage Centaur motor.

Image credit: — A capture of the X-37B in orbit. Image credit and copyright: Luke (Catching up)

There’s also been word afoot that future X-37B missions may return to Earth at the Kennedy Space Center, just like the Space Shuttle. To date, the X-37B has only landed at Vandenberg Air Force Base in California.

But there’s also another high interest payload being released along with a flock of CubeSats aboard AFPSC-5: The Planetary Society’s Lightsail-1.

About the size of a loaf of bread and the result of a successful Kickstarter campaign, LightSail is set to demonstrate key technologies in low Earth orbit before the Planetary Society’s main solar sail demonstrator takes to space in 2016.

The idea of using solar wind pressure for space travel is an enticing one. A big plus is the fact that unlike chemical propulsion, a solar sail does not need to contend with hauling the mass of its own fuel. The idea of using a solar sail plus a focused laser to propel an interstellar spacecraft has long been a staple of science fiction. But light-sailing technology has had a troubled history—the Planetary Society lost its Cosmos-1 mission launched from a Russian submarine in 2001. JAXA has fared better with its Venus-bound IKAROS, also equipped with a solar sail. To date, the IKAROS solar sail is the largest that has been deployed, at 20-metres on the diagonal.

Another use for space sail technology is the commanded reentry of spacecraft at the end of their mission life, as demonstrated by NanoSail-D2 in 2011.

Prospects of seeing LightSail may well be similar to what we had hunting for NanoSail-D2. Unfolded, LightSail will be 32 square meters in size, or about 5.6 meters on a side. NanoSail-D2 measured 3.1 meters on a side, and the reflective panels on the Iridium satellites which produce brilliant Iridium flares exceeding Venus in brightness measure about the size of a large rectangular door at 1 x 3 meters. Even the Hubble Space Telescope can flare on occasion as seen from the ground if one of its massive solar arrays catches the Sun just right.

The 39 degree orbital inclination angle will also limit visible passes to from about 45 degrees north to 45 degrees south latitude.

Hunting down X-37B and LightSail will push ground observing skills to the max. Like NanoSail-D2, LightSail probably won’t be visible to the naked eye until it flares. What we like to do is note when a faint satellite is set to pass by a bright star, then sit back with our trusty 15x 45 image-stabilized binoculars and watch. We caught sight of the ‘tool bag’ lost during an ISS EVA in 2009 in this fashion. There it was, drifting past Spica as a +7^th magnitude ‘star’. The key to this method is an accurate prediction—Heavens-Above now overlays orbital satellite passes on all-sky charts—and an accurate time source. We prefer to have WWV radio running in the background, as it’ll call out the time signal so we don’t have to take our eyes off the sky.

Veteran satellite watcher Ted Molczan recently discussed the prospects for spotting LightSail once it’s deployed. “By then, the orbit will be visible from the northern hemisphere during the middle of the night. The southern hemisphere may have marginal evening passes. Note that the high area to mass ratio with the sail deployed, combined with the low perigee height, is expected to result in decay as soon as a couple days after deployment.”

Read a further discussion concerning OTV-4 and associated payloads by Mr. Molczan on the See-Sat message board here.

The Planetary Society’s Jason Davis confirmed for Universe Today that LightSail will deploy 28 days after launch. But we may only have a slim two day observation window for LightSail between deployment and reentry.

A deployment of LightSail 28 days after launch would put it in the June 16^th timeframe.

“That’s the nominal mission time, yes,” Davis told Universe Today. “Our orbital models predict 2-10 days. For our 2016 flight, the mission will last at least four months.”

The Planetary Society plans to have a live ‘mission control center’ to track LightSail after P-POD deployment, complete with a Google Map showing pass predictions.

Satellite spotting can be a fun and addictive pastime, where part of the fun is sleuthing out what you’re seeing. Hey, some relics of space history such as the early Vanguards, Telstars, and Canada’s first satellite Alouette-1 are still up there! Nabbing these photographically are as simple as plopping your DSLR on a tripod, setting the focus and doing a time exposure as the satellite passes by.

Here’s to smooth solar sailing and clear skies as we embark on our quest to track down the X-37B and LightSail-1 in orbit.

-Follow us as @Astroguyz on Twitter, as we’ll be providing further info on orbits and visibility passes as they are made public.

May 13, 2015December 23, 2015 by David Dickinson

Review: Annals of the Deep Sky by Jeff Kanipe & Dennis Webb

Volumes 1 and 2 on sale now. Image credit: Willmann-Bell, Inc

Any lover of the night sky knows the value of a good star atlas and an astronomical handbook to guide your exploration of the universe. And while it’s true that more information exists out there than ever before online, much of it is intended for a general armchair astronomical audience, or is scattered about the web in disparate places…

But an exciting new series promises to be an essential must for deep sky observers. Annals of the Deep Sky: A Survey of Galactic and Extragalactic Objects by Jeff Kanipe and Dennis Webb is a through rundown of the night sky constellation-by-constellation which is aimed at the advanced observer. Mr. Kanipe is a science writer with 35 years experience, and Mr. Webb is a NASA engineer and observer with more than 25 years of experience exploring the night sky. If the names are familiar to deep sky fans, it might be because they also teamed up to produce the Arp Atlas of Peculiar Galaxies: A Chronicle and Observer’s Guide in 2006. Volumes 1 and 2 covering constellations in alphabetical order from Andromeda to Caelum are out now from Willmann-Bell, Inc., and the projected 12 volume set will cover all 88 constellations when completed. Volume 3 is due out in early 2016.

Messier 31 deconstructed by the Annals of the Deep Sky. Image credit: Willman-Bell, Inc — Messier 31 deconstructed by the *Annals of the Deep Sky*. Image credit: NASA/Willmann-Bell, Inc

Annals promises to join the ranks of some of the classic sky guides. Observers from the pre-digital era will recall the paucity of good observing resources available just a few decades ago. Growing up in rural northern Maine, even getting our hands on Sky and Telescope or Astronomy magazine was a daunting challenge, and we often gleaned knowledge of the astronomical goings on for the year from the tables of the Farmer’s Almanac. I remember hearing of the close 0.0312 AU passage past the Earth of Comet IRAS-Araki-Alcock in 1983, days after it had passed by! Contrast this with today, as message boards and Twitter alert us to new discoveries, sometimes within minutes.

Over the years, Ottewell’s yearly Astronomical Calendar has become a crucial resource as well.

Annals of the Deep Sky promises to be this generation’s answer to Burnham’s Celestial Handbook. You have to be of a certain age to remember Burnham’s, but that landmark three volume guide is one of the few hard copy resources that still resides on our desk well into the digital era. And Burnham’s has survived despite its use of now outdated 1950.0 stellar coordinates… that’s the kind of legendary staying power it has had in the amateur astronomy community!

A monument to Burnham's Celestial Handbook at the Lowell observatory in Flagstaff, Arizona. Image credit: David Dickinson — A monument to *Burnham’s Celestial Handbook* at the Lowell observatory in Flagstaff, Arizona. Image credit: David Dickinson

Annals of the Deep Sky begins with an outline of how to use the books, and a summary of basic observational astronomy and astrophysics. Like Burnham’s, Annals presents the field of observational astronomy beyond the solar system. But unlike Burnham’s—which was mainly text—the true magic of Annals lies in its extensive use of maps, diagrams and charts, all meant for the serious visual and photographic observer, both in planning observation runs and in the field. These also include some innovative ‘3-D’ style views through the constellations themselves as seen from our Earthly perspective. These views take the observer out through the plane of our galaxy and beyond as we peer out into the universe.

Annals of the Deep Sky also incorporates the latest discoveries and our understanding of the universe, as well as how our knowledge of astronomy and astrophysics got to where it is today. Annals not only provides the visual observer with handy field of view overlays for classic objects such as the Andromeda Galaxy (M31), but it also provides charts depicting camera sensor versus focal length and field of view for DLSR photography of key objects. To our knowledge, no other such resource for this specialized level of information exists for astrophotographers. We also enjoyed the graphic depictions of visual and spectroscopic binary star orbits, another tough item to dig up in research, even with today’s modern planetarium programs.

Representative views of visual (top) and spectroscopic binary orbits. Image credit: Willmann-Bell, Inc

The inclusion of history and astronomical lore is also a great touch that really makes the resource ‘pop’ in a vein similar to Burnham’s. This lends a fascinating dimension of astronomical history to the Annals that suits to a casual ‘shotgun’ reading style. Like Burnham’s, I can see discovering something new from a random opening of the Annals for years to come. A fine example is the lingering mystery of the Nova of 1860 in Volume 2 observed by Joseph Baxendell near Arcturus, a fascinating tale we’d never heard of.

We only wish that this awesome resource was also available in digital format so that we could carry this essential reference with us out in the field… we could easily envision cross-referencing information from a laptop planetarium program such as Starry Night or Stellarium at the eyepiece, with Annals of the Deep Sky cued up on the Kindle.

So grab that ‘Dobsonian light bucket’ and the first two volumes of Annals of the Deep Sky. This series promises to be an anticipated gem for many years to come. And hey, you can tell the next generation of hipster backyard observers that you remember what it was like before we had Annals of the Deep Sky to consult!

May 12, 2015December 23, 2015 by David Dickinson

A Guide to Saturn Through Opposition 2015

Getting closer... Saturn as seen on March 25th, 2015. Image credit: Efrain Morales

The month of May generally means the end of star party season here in Florida, as schools let out in early June, and humid days make for thunderstorm-laden nights. This also meant that we weren’t about to miss the past rare clear weekend at Starkey Park. Jupiter and Venus rode high in the sky, and even fleeting Mercury and a fine pass of the Hubble Space Telescope over central Florida put in an appearance.

But the ‘star’ of the show was the planet Saturn as it appeared at nightfall low to the southeast. Currently rising about 9:00 PM local, Saturn is joining the evening skies as it approaches opposition next week.

This also means we’ve got every naked eye planet set for prime time evening viewing this week with the exception of Mars, which reaches solar conjunction on June 14, 2015. Mercury will be the first world to break this streak, as it descends into the twilight glare by mid-May.

The apparent path of Saturn from May to November 2015. Image credit: Starry Night Education software

Saturn reaches opposition for 2015 on May 23^rd at 1:00 Universal Time (UT), which equates to 9:00 PM EDT the evening prior on May 22 at nearly 9 astronomical units (AU) distant. Oppositions of Saturn are getting slightly more distant to the tune of 10 million kilometers in 2015 versus last year as Saturn heads towards aphelion in 2018. Saturn crosses eastward from the astronomical constellation of Scorpius in the first week of May, and spends most of the remainder of 2015 in Libra before looping back into the Scorpion in mid-October. The first of June finds Saturn just over a degree southward of the +4th magnitude star Theta Librae. Saturn takes nearly 30 Earth years to complete one orbit, meaning that it was right around the same position in the sky in 1985, and will appear so again in 2045. Relatively speedy Jupiter also overtakes Saturn as seen from the Earth about once every 20 years, as it last did on 2000 and is set to do so again in 2020.

And though series of occultations of Saturn by the Moon wrapped up in 2014 and won’t resume again until December 9, 2018, there’s also a good chance to spy Saturn two degrees away from the daytime Moon with binoculars on June 1st just 24 hours prior to Full:

Looking east on the evening of June 1st just before sunset. Image credit: Stellarium

The tilt of the rings of Saturn is also slowly widening from our Earthbound perspective. At opposition, Saturn’s rings subtend 43” across, and the ochre disk of Saturn itself spans 19”. Incidentally, on a good pass, the International Station has a visual span roughly equivalent to Saturn plus rings. In 2015, the rings are tilted 24 degrees wide and headed for a maximum approaching 27 degrees in 2017. The rings appeared edge on in 2009 and will do so again in 2025.

Getting wider... our evolving view of Saturn's rings. Image credit and copyright: Andrew Symes — Getting wider… our evolving view of Saturn’s rings. Image credit and copyright: Andrew Symes

Also, keep an eye out for the Seeliger effect. Also sometimes referred to as the ‘opposition surge,’ this is a retroreflector-style effect that causes an outer planet to brighten up substantially on the days approaching opposition. In the case of Saturn and its rings, this effect can be especially dramatic. Not only is the disk of Saturn and the billions of icy snowballs casting shadows nearly straight back as seen from our vantage point near opposition, but a phenomenon known as coherent backscatter serves to increase the collective brightness of Saturn as well. You see the same effect at work as you drive down the Interstate at night, and highway signs and retroreflector markers down the center of the road bounce your high-beams back at you.

Highway retroreflectors in action. Image credit: Wikimedia Commons/Public Domain

We’ve seen some pretty nifty image comparisons demonstrating the Seeliger effect on Saturn, but as of yet, we haven’t seen an animation of the same. Certainly, such a feat is well within the capacities of amateur astronomers out there… hey, we’re just throwing that possibility out into the universe.

Through a small telescope, the moons of Saturn become readily apparent. The brightest of them all is Titan at magnitude +9, orbiting Saturn once every 16 days. Discovered by Dutch astronomer Christiaan Huygens on March 25, 1655 using a 63 millimeter refractor with an amazing 337 centimeter focal length, Titan would easily be a planet in its own right were it directly orbiting the Sun. Titan also marks the most distant landing of a spacecraft ever carried out by our species, with the descent of the European Space Agency’s Huygens lander on January 14, 2005. Huygens hitched a ride to Saturn aboard NASA’s Cassini spacecraft, which is slated to end its mission with a destructive reentry over the skies of Saturn in 2017. Saturn has 62 known moons in all, and Enceladus, Mimas, Tethys, Dione, Rhea and two-faced Iapetus are all visible from a backyard telescope.

You can check out the current position of Saturn’s major moons (excluding Iapetus) here.

And speaking of Iapetus, the outer moon would make a fine Saturn-viewing vantage point, as it is the only major moon with an inclined orbit out of the ring plane of Saturn:

Expect our Saturn observing resort to open there one day soon.

Up for a challenge? Standard features to watch for include: the shadow of the rings on the planet, and the shadow of the planet across the rings, as well as the Cassini division between the A and B ring… but can you see the disk of the planet through the gap? High magnification and steady seeing are your friends in this feat of visual athletics… catching sight of it definitely adds a three dimensional quality to the overall view.

Let ‘the season of Saturn 2015’ begin!

May 10, 2015December 23, 2015 by Bob King

Head Held High, Comet Lovejoy Does the Polar Plunge

Comet C/2014 Q2 Lovejoy on May 7 with its emerald coma and faint gas tail. Lovejoy is currently around magnitude +7.5 and slowly fading. Credit: Rolando Ligustri

Lots of towns hold a polar plunge fundraising event in the winter. Duluth, Minnesota’s version, where participants jump in Lake Superior every February, might just be the coldest. Comet Lovejoy’s a season behind, but sure enough, it’s following suit, diving deep into the dark waters of the north celestial pole this month.

I dropped in on our old friend last night, when it glowed only 8° from the North Star. In 8×40 binoculars, the comet was faintly visible as a hazy blob of light with a brighter center. Not a sight to knock you over, but the fact that this comet is still visible in binoculars after so many months makes it worthwhile to seek out. Moonless skies for the next 10-11 nights means lots of opportunities.

Just face the North Star (Polaris) to begin tracking Comet Lovejoy. Stars are shown to magnitude +8. Click for a larger version. Created with Stellarium — Just face the North Star (Polaris) to begin tracking Comet Lovejoy. The map shows the sky facing north around 10:30 p.m. local time in mid-May. Stars are plotted to magnitude +8. Click for a larger version. Source: Chris Marriott’s SkyMap

Unless a new comet is discovered, Lovejoy will continue to remain the only “bright” comet visible from mid-northern latitudes for some time. There’s a tiny chance Comet C/2014 Q1 PanSTARRS will wax bright enough to see in twilight in early July, but it will be very low in the northwestern sky at dusk and visible for a few nights at most. Only C/2013 US10 Catalina offers the chance for a naked eye / binocular appearance, when it re-emerges from the solar glare in the latter half of November in the morning sky.

Southern hemisphere observers have more to smile about with Comet C/2015 G2 MASTER currently flaunting its fluff at magnitude +6.6 or just under the naked eye limit. They’ll also get a far better view of C/2014 Q1 PanSTARRS come this July and August.

Wide view of the sky facing north in mid-May around 10:30 p.m. local time. Use the Pointer stars in the Big Dipper to point you to Polaris and from there to the comet. Source: Chris Marriott's SkyMap — Wide view of the sky facing north in mid-May around 10:30 p.m. local time. Use the Pointer stars in the Big Dipper to point you to Polaris and from there to the comet. Source: Chris Marriott’s SkyMap

Through a telescope, Lovejoy still shows off a round, 6 arc minute diameter coma (one-fifth as wide as a full moon) and a denser, brighter core highlighted by a starlike false nucleus. We call it false because the true comet nucleus, probably no more than a few kilometers across, hides within a dusty cocoon of its own making. Only spacecraft have been able to get close enough for a clear view of comet nuclei. Each shows a unique and usually non-spherical shape because comets aren’t massive enough for their own self-gravity to crush them into spheres the way larger moons and planets do. If you’re a single object and big, being spherical comes naturally.

Comet Lovejoy will be closest to the imaginary point in the sky called the north celestial pole on May 29. Polaris lies 0.75° from the pole and describes a small circle 1.5° in diameter around it each day. Source: Stellarium

In my 15-inch (37-cm) telescope a faint wisp of a tail poked from the coma to the north. Looking at the map, you can see the comet’s headed due north through Cepheus toward Polaris, the North Star. Each passing night, it draws closer to the sky’s celestial pivot point, missing it by just 1° on the evenings of May 27 and 28. Closest approach to the north celestial pole, which marks the spot in the sky toward which Earth’s north polar axis currently points, occurs on May 29 with a separation of 54 arc minutes or just under a degree.

Finding Polaris is easy. Just draw a line through the two stars at the end of of the Big Dipper’s Bowl toward the horizon. The first similarly bright star you run into is the North Star. Using the map, you can navigate from Polaris to the fuzzy comet with either binoculars or telescope.

May 7, 2015December 23, 2015 by David Dickinson

Tales (Tails?) of Two Comets: Prospects for Q1 PanSTARRS & G2 MASTER

Comet G2 MASTER passes near the Helix Nebula in Aquarius on the night of April 21st.

Did you catch the performance of Comet C/2014 Q2 Lovejoy earlier this year? Every year provides a few sure bets and surprises when it comes to binocular comets, and while we may still be long overdue for the next truly ‘Great Comet,’ 2015 has been no exception.

This week, we’d like to turn your attention to two icy visitors to the inner solar system which may present the best bets comet-wise over the next few weeks: Comets C/2014 Q1 PanSTARRS and C/2015 G2 MASTER.

First up is Comet C/2014 Q1 PanSTARRS. Discovered on August 16, 2014 by the Panoramic Survey Telescope & Rapid Response System (PanSTARRS) based atop Mount Haleakala in Hawaii, we’ve known of the potential for Q1 PanSTARRS to put on a decent show this summer for a while. In fact, it made our roundup of comets to watch for in our 101 Astronomical Events for 2015. Q1 PanSTARRS currently sits at +11^th magnitude as a morning sky object in the constellation Pisces. On a 39,000 year long parabolic orbit inclined 45 degrees relative to the Earth’s orbit, Q1 PanSTARRS will leap up across the ecliptic on May 17^th and perhaps reach +3^rd magnitude as it nears perihelion in early July and transitions to the evening sky.

An image of Comet C/2014 Q1 PanSTARRS shortly after discovery. Credit and copyright: Efrain Morales Rivera.

Though it may put on its best show in July and August, a few caveats are in order. First, we’ll be looking at Q1 PanSTARRS beyond the summer Sun, and like C/2011 L4 PanSTARRS a few years back, it’ll never leave the dusk twilight, and will always appear against a low contrast backdrop.

May June (AM) Starry Night Education software. — The May-June path of Comet Q1 PanSTARRS through the dawn sky as seen from latitude 30 degrees north. Credit: Starry Night Education software.

Here are some notable upcoming events for Comet C/2014 Q1 PanSTARRS:

(Unless otherwise noted, a ‘close pass’ is here considered to be less than one degree of arc, about twice the diameter of a Full Moon.)

May 16: Passes into the constellation Aries.

May 16: The waning crescent Moon passes 2 degrees distant.

May 17: Crosses northward through the ecliptic.

May 20: May break +10^th magnitude.

June 11: Passes in to the constellation Taurus.

June 12: Passes 2 degrees from M45 (The Pleiades).

June 15: May break 6^th magnitude.

June 20: Passes into Perseus.

June 21: Passes into Auriga.

June 23: Passes +2.7 magnitude star Hassaleh (Iota Aurigae).

June 25: Passes the +7.5 magnitude open cluster IC 410.

June 26: Passes +6 magnitude Pinwheel Open Cluster (M36).

Evening path. Starry Night Education software. — The July-August evening path of Q1 PanSTARRS as seen from latitude 30 degrees north. Credit: Starry Night Education software.

July 2: Crosses into Gemini.

July 3: Passes the +3.6 magnitude star Theta Geminorum.

July 5: Passes 10 degrees north of the Sun and into the evening sky.

July 6: Passes midway between Castor and Pollux.

July 6: Reaches perihelion at 0.315 astronomical units (AU) from the Sun.

July 7: May top out at +3^rd magnitude.

July 8: Crosses into Cancer.

July 12: Photo Op: passes M44, the Beehive Cluster.

July 13: Sits 30 degrees from Comet C/2015 G2 MASTER (see below).

July 15: May drop below +6^th magnitude.

July 15: Crosses the ecliptic southward.

July 17: The waxing crescent Moon passes 1.5 degrees south.

July 19: Crosses into Leo.

July 20: Closest to Earth, at 1.18 AU distant.

July 21: Less than 10 degrees from Jupiter and Venus.

July 22: Crosses into Sextans.

July 26: Crosses the celestial equator southward.

August 4: Crosses into Hydra.

August 5: Crosses into Crater.

August 18: Crosses back into Hydra.

August 30: Crosses into Centaurus.

September 1: Drops below +10^th magnitude.

Light curve. — The projected light curve of Q1 PanSTARRS over time. The black dots represent observations. Credit: *Weekly Information about Bright Comets*.

The next comet on deck is the recently discovered C/2015 G2 MASTER. If you live in the southern hemisphere, G2 MASTER is the comet that perhaps you haven’t heard of, but should be watching in the dawn sky. Discovered last month on April 7 as by MASTER-SAAO (The Russian built Mobile Astronomical System of Telescope-Robots at the South African Astronomical Observatory), this is not only the first comet bagged by MASTER, but the first comet discovery from South Africa since 1978. G2 MASTER has already reached magnitude +7 and is currently crossing the constellation Sculptor. It is also currently only visible in the dawn sky south of 15 degrees north latitude, but images already show a short spiky tail jutting out from G2 MASTER, and the comet may rival Q2 Lovejoy’s performance from earlier this year. Expect G2 MASTER to top out at magnitude +6 as it nears perihelion in mid-May. Observers around 30 degrees north latitude in the southern U.S. should get their first good looks at G2 MASTER in late May, as it vaults up past Sirius and breaks 10 degrees elevation in the evening sky after sunset. Again, as with Q1 PanSTARRS, cometary performance versus twilight will be key!

An April 10th image of Comet C/2015 G2 MASTER, plus an initial projected light curve versus solar elongation over time. Credit: Ernesto Guido & Nick Howes/Remanzacco Observatory

Here are some key dates with astronomical destiny for Comet G2 MASTER over the coming weeks:

May 9: Crosses into Fornax.

May 15: May top out at +6^th magnitude.

May 13: Closest to Earth at 0.47 AU.

May 14: Crosses into Eridanus.

May 16: Crosses into Caelum.

May 17: Crosses into Lepus.

May 20: Passes the +3.8 magnitude star Delta Leporis.

May 23: Crosses into Canis Major.

May 23: Reaches perihelion at 0.8 AU from the Sun.

May 27: Crosses into Monoceros.

May 28: Passes the +5.9 magnitude Open Cluster M50.

Comet G2 MASTER imaged on May 7th. Credit and copyright: Adriano Valvasori

June 8: Crosses northward over the celestial equator and into the constellation Canis Minor.

July 1: May drop below 10^th magnitude.

G2 MASTER also crosses SOHO’s field of view on July 24^th through August 4^th, though it may be too faint to see at this point.

Here are the Moon phases for the coming weeks to aid you in your comet quest:

Full Moons: June 2^nd, July 2^nd, July 31^st, August 29^th.

New Moons: May 18^th, June 16^th, July 16^th, August 14^th.

Binoculars are our favorite ‘weapon of choice’ for comet hunting. Online, Heavens-Above is a great resource for quickly and simply generating a given comet’s sky position in right ascension and declination; we always check out the Comet Observers Database and Seiichi Yoshida’s Weekly Information about Bright Comets to see what these denizens of the outer solar system are currently up to.

Good luck, and be sure to regale us with your comet-hunting tales of tragedy and triumph!

April 30, 2015December 23, 2015 by David Dickinson

Crossing Quarters: Would the Real Astronomical Midway Point Please Stand Up?

Happy May Day Eve!

Maybe May 1^st is a major holiday in your world scheme, or perhaps you see it as the release date of Avengers: Age of Ultron.

We’re approximately mid-way between the March equinox and the June solstice this week, as followers of the Gregorian calendar flip the page tomorrow from April to May. Though astronomical spring began back on March 20^th for the northern hemisphere, May 1^st is right around the time it starts to feel like spring weather for most of the residents of mid- northern latitudes.

Blame solar insolation, as the Sun transits ever higher in its daily trek towards the June solstice. Sure, the 23 degree 26’ 21” axial tilt of our fair planet is the reason for the season, and the pair of equinoxes and solstices are easily marked… but did you know that there are four other astronomical waypoints along the ecliptic that aren’t so readily defined?

A ‘sidewalk sundial’ in front of the Flandrau observatory in Tucson, Arizona. Credit and copyright: Dave Dickinson

Welcome to the curious world of cross-quarter days. Tomorrow, May 1^st is also known as May Day, which is one such holiday. Perhaps, if you’re reading this in the remaining socialist states of China, Cuba or North Korea, you observe May Day as a major communist holiday. True story: back in our Cold Warrior days, May Day usually meant deployment to a forward location to chase Soviet Bear bombers out of friendly air space.

The cycle of four cross quarter days and four quarter (two solstices and two equinoxes) comprise the modern ‘Wheel of the Year’ on the Pagan calendar. The Christian holidays of Easter and Christmas also have their equinoctial and solstice roots.

The other three cross quarter holidays on our modern calendar are: Groundhog Day (February 2nd), Lammas Day (August 1st) and Halloween on October 31^st. It’s great to see suburbanites don garb and request treats in a yearly re-enactment of ancient ritual.

But the solstice and equinoctial points aren’t fixed on the Gregorian calendar, but instead drift as we attempt to keep measured time in sync with astronomical time. These midway dates should actually be referred to as ‘cross-quarter tie-in holidays,’ as the actual midpoint between solstice and equinox can be determined in several different ways.

Here are the technical mid-points for 2015:

*Note that Easter in the Catholic Church is defined by the First Council of Nicaea in 325 A.D. as the first Sunday after the First Full Moon after March 21^st. It can, therefore, fall anywhere from March 22nd to April 25th. The Eastern Orthodox Church uses the older Julian calendar, meaning the dates of Easter for the two sects of Christianity do not always coincide. Keep in mind, however, that March 21^st is only an approximation for the northward equinox, which, in the 20^th through 21^st century, can fall anywhere from March 19^th to March 21st.

Marking the technical midway point in declination simply means noting when the Sun crosses 11 degrees 43’ 10” north or south. Note that these always cluster with a bias towards the equinoxes, as the apparent motion of the Sun is faster in declination as it moves at a steeper angle around these dates. Sol’s motion in declination is shallowest near the solstices, which is why the gain and loss of daylight is least noticeable around these dates.

The true position of the Sun on May 1st. Credit: Stellarium

And the second way we can mark the technical midpoints is strictly in time… but keep in mind, the seasons are not precisely equal in length due to the elliptical orbit of the Earth. Though it may not seem like it, Earth actually reaches perihelion and moves slightly faster around the Sun in early January during the depths of northern hemisphere winter!

And our friend the precession of the equinoxes plays a role as well, moving the two equinoctial points where the ecliptic and the celestial equator intersect once all the way around the sky as the Earth completes one ‘wobble’ every 26,000 years… live out a typical 72 year life span, and the equinoctial points will have moved about one degree, or twice the diameter of a Full Moon.

An Earthbound analemma simulation. Credit: Starry Night Education Software

And you can ‘observe’ the motion of the Sun and trace out the figure 8 shape of the analemma noting the quarter and cross-quarter points by imaging the Sun at the same time of the day once every week or so for a year:

Note: make sure you stay on local solar time in your yearlong analemma quest… don’t let the archaic vagaries of Daylight Saving Time throw you off by an hour!

Mars analemma. Credit: — A Mars analemma as seen from Opportunity. Credit: NASA/JPL/Cornell/ASU/TAMU

And other planets have extraterrestrial analemmas as well. In the case of Mars, the path of the Sun over the Martian year is actually teardrop-shaped:

However you reckon the springtime mid-point, don’t miss any local ‘May Day-henge’ alignments coming to a horizon near you.

April 21, 2015December 23, 2015 by David Dickinson

The 2015 Lyrid Meteors Peak Tomorrow Night!

A lucky capture of a 2013 Lyrid meteor. Image credit and copyright: John Chumack

April showers bring May flowers, and this month also brings a shower of the celestial variety, as the Lyrid meteors peak this week.

And the good news is, 2015 should be a favorable year for the first major meteor shower of the Spring season for the northern hemisphere. The peak for the shower in 2015 is predicted to arrive just after midnight Universal Time on Thursday April 23^rd, which is 8:00 PM EDT on the evening of Wednesday April 22^nd. This favors European longitudes right around the key time, though North America could be in for a decent show as well. Remember, meteor showers don’t read forecasts, and the actual peak can always arrive early or late. We plan to start watching tonight and into Wednesday and Thursday morning as well. April also sees a extremely variable level of cloud cover over the northern hemisphere, another reason to start your meteor vigil early on if skies are clear.

The radiant for the 2015 Lyrids as seen from 40 degrees north latitude at local midnight. Credit: Stellarium.

Another favorable factor this year is the phase of the Moon, which is only a slender 20% illuminated waxing crescent on Wednesday night. This means that it will have set well before local midnight when the action begins.

The source of the Lyrid meteors is Comet C/1861 G1 Thatcher, which is on a 415 year orbit and is expected to come back around again in 2276 A.D. 1861 actually sported two great comets, the other being C/1861 J1, also known as the Great Comet of 1861.

The orientation of the Sun, Moon, and the Lyrid radiant at the expected peak of the shower at 24UT/20EDT April 22nd. credit: Stellarium

The Lyrids typically exhibit an ideal Zenithal Hourly Rate (ZHR) of 15-20 per hour, though this shower has been known to produce moderate outbursts from time to time. In 1803 and 1922, the Lyrids produced a ZHR of 100 per hour, and in recent times, we had an outburst of 250 per hour back in 1982. Researchers have tried over the years to tease out a periodicity for Lyrid outbursts, which seem erratic at best. In recent years, the Lyrids hit a ZHR of 20 (2011), 25 (2012), 22 (2013), and 16 last year in 2014.

Keep in mind, we say that the ZHR is an ideal rate, or what you could expect from the meteor shower with the radiant directly overhead under dark skies: expect the actual number of meteors observed during any shower to be significantly less.

A 2014 Lyrid fireball. Credit: The UK Meteor Network

The radiant for the Lyrids actually sits a few degrees east of the bright star Vega across the Lyra border in the constellation Hercules. They should, in fact, be named the Herculids! In mid-April, the radiant for the April Lyrids has already risen well above the northeastern horizon as seen from latitude 40 degrees north at 10 PM local, and is roughly overhead by 4 AM local. Several other minor showers are also active around late April, including the Pi Puppids (April 24^th), the Eta Aquarids (May 6^th), and the Eta Lyrids (May 9^th). The constellation of the Lyre also lends its name to the June Lyrids peaking around June 6^th.

The April Lyrids are intersecting the Earth’s orbit at a high 80 degree angle at a swift velocity of 49 kilometres per second. About a quarter of the Lyrid meteors are fireballs, leaving bright, persistent smoke trains. It’s a good idea to keep a set of binoculars handy to study these lingering smoke trails post-passage.

The Lyrids also have the distinction of having the longest recorded history of any known meteor shower. Chinese chronicles indicate that “stars dropped down like rain,” on a late Spring night in 687 BC.

Observing a meteor shower requires nothing more than a set of working ‘Mark-1 eyeballs’ and patience. The International Meteor Organization always welcomes reports of meteor counts from observers worldwide to build an accurate picture of evolving meteor debris streams. You can even hear meteor ‘pings’ via FM radio.

Expect the rate to pick up past local midnight, as the Earth plows headlong into the oncoming meteor stream. Remember, the front of the car gets the love bugs, an apt analogy for any Florida resident in mid-April.

A composite view of the 2012 Lyrids plus sporadic meteors. Credit: NASA/MSFC/Danielle Moser

Catching a photograph of a Lyrid or any meteor is as simple as plopping a DSLR down on a tripod and doing a series of 30 second to several minute long time exposures. Use the widest field of view possible, and aim the camera off at about a 45 degree angle from the radiant to catch the meteors sidelong in profile. Be sure to take a series of test shots to get the ISO/f-stop combination set for the local sky conditions.

Don’t miss the 2015 Lyrids, possibly the first good meteor shower of the year!

April 17, 2015December 23, 2015 by Bob King

Lunar ‘Fountain of Youth’ Challenge / Mercury Returns with Gusto

A day-old Moon floats over the Spirit Mountain ski hill in Duluth, Minn. this past January. Credit: Bob King

16th century Spanish explorer Juan Ponce de León looked and looked but never did find the Fountain of Youth, a spring rumored to restore one’s youth if you bathed or drank from its waters. If he had, I might have interviewed him for this story.

Sunday night, another symbol of youth beckons skywatchers the world over. A fresh-faced, day-young crescent Moon will hang in the western sky in the company of the planets Mars and Mercury. While I can’t promise a wrinkle-free life, sighting it may send a tingle down your spine reminding you of why you fell in love with astronomy in the first place.

Look low in the west-northwest sky Sunday evening April 19 to spot the day-old crescent Moon alongside Mars and returning Mercury. Source: Stellarium — Look low in the west-northwest sky Sunday evening April 19 to spot the day-old crescent Moon alongside Mars and returning Mercury. Brilliant Venus will help you get oriented. This map shows the sky around 40 minutes after sunset but you can start as early as 30 minutes especially if you’re using binoculars. Source: Stellarium

The Moon reaches New Moon phase on Saturday, April 18 during the early afternoon for North and South America. By sunset Sunday, the fragile crescent will be about 29 hours old as seen from the East Coast, 30 for the Midwest, 31 for the mountain states and 32 hours for the West Coast. Depending on where you live, the Moon will hover some 5-7° (three fingers held at arm’s length) above the northwestern horizon 40 minutes after sunset. To make sure you see it, find a location with a wide-open view to the west-northwest.

Earthshine gets easier to see once the Moon moves a little further from the Sun and into a dark sky. Our planet provides enough light to spot some of the larger craters. Credit: Bob King — Earthshine gets easier to see as the Moon moves further from the Sun and the crescent fills out a bit. Our planet provides enough light to spot some of the larger craters. Credit: Bob King

While the crescent is illuminated by direct sunlight, you’ll also see the full outline of the Moon thanks to earthshine. Sunlight reflected off Earth’s globe faintly illuminates the portion of the Moon not lit by the Sun. Because it’s twice-reflected, the light looks more like twilight. Ghostly. Binoculars will help you see it best.

Now that you’ve found the dainty crescent, slide your eyes (or binoculars) to the right. That pinpoint of light just a few degrees away is Mars, a planet that’s lingered in the evening sky longer than you’ve promised to clean out the garage. The Red Planet shone brightly at opposition last April but has since faded and will soon be in conjunction with the Sun. Look for it to return bigger and brighter next May when it’s once again at opposition.

Diagram showing Mercury's position and approximate altitude above the horizon during the current apparition. Also shown are the planet's phases, which are visible in a telescope. Credit: Stellarium, Bob King — Diagram showing Mercury’s position and approximate altitude above the horizon during the current apparition. Also shown are the planet’s changing phases, which are visible in a telescope. Credit: Stellarium, Bob King

To complete the challenge, you’ll have to look even lower in the west to spot Mercury. Although brighter than Vega, it’s only 3° high 40 minutes after sunset Sunday. Its low altitude makes it Mercury is only just returning to the evening sky in what will become its best appearance at dusk for northern hemisphere skywatchers in 2015.

As an inner planet, Mercury goes through phases just like Venus and the Moon. We see it as everything from a crescent to a "full moon" as it angle to the Sun changes during its 88-day orbit. Credit: ESO — As an inner planet, Mercury goes through phases just like Venus and the Moon. We see it morph from crescent to “full moon” as its angle to the Sun changes during its revolution of the Sun. Credit: ESO

Right now, because of altitude, the planet’s a test of your sky and observing chops, but let the Moon be your guide on Sunday and you might be surprised. In the next couple weeks, Mercury vaults from the horizon, becoming easier and easier to see. Greatest elongation east of the Sun occurs on the evening of May 6. Although the planet will be highest at dusk on that date, it will have faded from magnitude -0.5 to +1.2. By the time it leaves the scene in late May, it will become very tricky to spot at magnitude +3.5.

Mercury’s a bit different from Venus, which is brighter in its crescent phase and faintest at “full”. Mercury’s considerably smaller than Venus and farther from the Earth, causing it to appear brightest around full phase and faintest when a crescent, even though both planets are largest and closest to us when seen as crescents.

Not to be outdone by Venus earlier this month, Mercury passes a few degrees south of the Pleiades star cluster on April 29. The map shows the sky facing northwest about 50 minutes after sunset. Source: Stellarium — Not to be outdone by the Venus-Pleiades conjunction earlier this month, Mercury passes a few degrees south of the star cluster on April 29. The map shows the sky facing northwest about 50 minutes after sunset. Source: Stellarium

Venus makes up for its dwindling girth by its size and close proximity to Earth. It also doesn’t hurt that it’s covered in highly reflective clouds. Venus reflects about 70% of the light it receives from the Sun; Mercury’s a dark world and gives back just 7%. That’s dingier than the asphalt-toned Moon!

Good luck in your mercurial quest. We’d love to hear your personal stories of the hunt — just click on Comments.

April 14, 2015December 23, 2015 by David Dickinson

Help Researchers Track Comet 67/P Through Perihelion

Calling all light-bucket scope owners: the folks at the European Space Agency want to enlist you in the quest to monitor Comet 67P/Churyumov-Gerasimenko from our Earthbound perspective through perihelion later this summer.

“We are looking to bring an entire community of professional and amateur observers together,” said Rosetta Coordinator of Amateur Observations for Comet 67/P C-G Padma A. Yanamandra-Fisher in a recent press release. “When else can you observe a comet at the same time a spacecraft is viewing it at close proximity and escorting it to perihelion, and be able to correlate both sets of findings?

The Rosetta story thus far has been an amazing tale of discovery. We’ve extensively chronicled the historic approach of the Rosetta spacecraft as the rubber-duck-shaped comet grew in its view here at Universe Today. The world also held its collective breath as the Philae lander, the little washing Euro- washing machine-sized spacecraft that could, descended on to the alien surface. Heck, Philae even knocked a Kardashian out of the top trending spot worldwide, a feat in and of itself.

We also documented the Spinal Tap-esque “None more black” nature of the comet.

Prospects in 2015: As of this writing, Comet 67P/C-G is 1.9 AU from the Sun and closing. The ‘P’ in ‘67/P’ stands for ‘short term (less than 200 years) periodic,’ and the comet orbits the Sun once every 6.44 years. Perihelion for 67/P occurs on August 13^th, 2015 when the comet reaches a distance of 1.24 AU ( 191 million kilometres) from the Sun.

Discovered in 1969 by the Kiev University’s Klim Ivanovych Churyumov while examining a photograph taken by Svetlana Gerasimenko, this is the comet’s seventh apparition. Currently shining at +18th magnitude in the constellation Aquarius, Comet 67P C-G will vault up in the early morning sky for northern hemisphere observers and cross the ecliptic plane in the last week of July, at 43 degrees elongation west of the Sun.

The comet is expected to reach a maximum brightness of +11^th magnitude near perihelion. Historically, 67P – like most comets – tend to under-perform before perihelion, only to have an energetic lingering outburst phase post-perihelion.

“With each apparition we see it (67P) behave differently.” Yanamandra-Fisher said. “These legacy data sets will aid in our knowledge of this comet, especially when used in combination with the data gathered by the Rosetta spacecraft and the new ground observations made this year.”

Time on professional scopes is always chronically in short supply, with more astronomers and targets to observe than there are telescopes available. That’s where amateur observers come in. Many private backyard observatories have instruments that would be the envy of many a major institution. Though the press release suggests that the minimum aperture size needed to observe 67P this summer is 14-inches (35 cm), we urge 10” or 12” inch scope owners – especially those who have the latest generation of Mallincam and faint object CCD imagers – to give it a try. We’ve seen some amazing results with these, even during quick casual observing sessions such as public star parties! The Rosetta team is looking for everything from professional grade images, to sketches and visual observations with magnitude estimations.

Of course, hunting faint comets is a daunting task at best. +10^th magnitude is generally our cut-off for ‘is interesting enough to alert the public’ in terms of novae or comets, though we’ll let 67/P ‘into the club’ due to its celebrity status.

Comet 67/P from June 23rd, 2014. Image credit and copyright: Efrain Morales

To add to the challenge, the comet is only visible against a dark sky during a brief pre-dawn window. You’ll need a planetarium program (we use Starry Night Pro) to generate good finder charts down to 15^th magnitude or so. Keep in mind, comets also typically appear a bit fainter visually than stars of the same magnitude due to the fact that said brightness is spread out over a broad surface area.

ESA also has a great page with an ephemeris generator to help you in your 67/P quest.

“This is truly interactive science that people of all observing levels can participate in- from amateurs to professionals.” Yanamandra-Fischer said in closing.

Other comets to watch for in 2015 include still bright 2014 Q2 Lovejoy, C/2013 US10 Catalina, C/2014 Q1 PanSTARRS, and 19P/Borrelly.

What’ll happen as 67P approaches perihelion? Will those two gigantic lobes crack and separate as Rosetta and the world looks on? Now, I’d pay to see that!

A light bucket scope at the Bruneau Dunes observatory suitable for a faint comet quest. Image credit: David Dickinson

-Register for the Rosetta observation campaign here.

April 13, 2015December 23, 2015 by David Dickinson

Firefly Astronomy

Light makes life, and sometimes, life returns the favor. There’s nothing more magical than watching fireflies flit across a starlit field on a summer’s night. Growing up in Northern Maine, summer was an all-too swiftly passing season, and fireflies had to put on their displays in a brief profusion of frenzied activity around late July and early August before the weather turned once again towards another long harsh winter.

Fireflies remind us of the ephemeral nature of existence, that’s for sure. And they’re much more welcome by summertime campers on vigil for the August Perseids than oh, say the ubiquitous mosquito or vicious black flies…

A recent amazing capture (see the intro image) came to us courtesy of Steed Yu. Shooting from the shores of Lake Natron in Tanzania, he managed to capture an amazing composition of fireflies and those ‘fireflies of the cosmos,’ in the form of a star-dappled southern hemisphere sky.

Taken on February 24^th 2015 just south of the equator, this is simply an amazing image. Don’t forget, though it’s towards the end winter time up here in the northern hemisphere in late February, it’s the tail end of the summer south of the equator.

The photographer had this to say about his ‘Carnival of Fireflies’:

The Night of Lake Natron belongs to the stars. Without any artificial light disturbing the pure sky, one can easily see the Southern Milky Way, as well as sparkling starlights scattered in it, such as the most distinctive constellation Southern Cross and our nearest stellar neighbours Alpha Centauri. The Night of Lake Natron belongs to the firefly too. These glowing elves were flying up and down among the lush grass on both sides of a ravine stream, like a flowing “Firefly Way”, as if to contest with the Milky Way. On the quiet starry night, the fireflies held a grand carnival.

Fireflies shine through a method known as bioluminescence, producing a cold light via a chemical process using the chemical luciferin that causes their abdomen to glow. This aids mating and mate selection, and even firefly larvae have been known to glow. Other deep sea and cave-dwelling species of fish and insects have been known to use a similar signaling method in the absence of ambient light.

You can see the stars of the southern Milky Way and the Southern Cross high above the African night shining in their own particular fashion via nuclear fusion, using the proton-proton chain reaction to shed their ancient photons of light onto the nighttime scene from beyond the cold dust lanes of the Coal Sack.

We’ve managed to observe the sky from the southern hemisphere five times from three different continents over the years, and can attest that all of the ‘good stuff’ is in the southern sky, where the core of our home Milky Way galaxy arcs high overhead.

Such ‘Firefly Time-lapse Astronomy’ is as easy as parking a DSLR with a wide-field of view lens on a tripod and shooting 10-60 second time exposures. Fellow Universe Today writer Bob King wrote a piece last year on his firefly astronomy adventures.

And check out this amazing video sequence by Vincent Brady taken in the summer of 2013 from Lake of the Ozarks, Missouri:

Humans have also mastered the art of creating light and luminescence via technology as well. This has served as a way to ‘push back the night,’ and our 24 hour civilization has come to rely on this mimicry of nature as we demonstrate our prowess at illumination. This often has a cost, however, as we banish the beauty of the night sky to a distant memory. We’ve also had the dubious pleasure of observing and conducting impromptu sidewalk star parties from downtown Tampa and the Las Vegas strip, arguably some of the most light-polluted locales in the world. On such nights, only the Moon, planets and perhaps the odd bright double stars are the only viable targets.

But all is not lost. Perhaps wasteful light pollution is only an adolescent phase that civilizations go through. One SETI search strategy has even suggested that we may be able to detect ET via light pollution from alien cities on the night side of prospective planets … perhaps some race of ‘intelligent fireflies’ straight out of science fiction will use bio-chemical signaling for communication?

All great thoughts to ponder on the star-filled summer nights ahead, as fireflies swarm around us. We move that if we ever become an interstellar species that we bring the noble firefly along for the ride… but please, let’s leave light pollution and mosquitoes behind.