An occultation occurs when one foreground celestial object completely obscures another. Technically, a total solar eclipse is an occultation of the Sun by the Moon, although it’s never referred to as such. The term finds modern usage mainly for the blocking of stars and planets by the Moon. Very occasionally, an asteroid or planet can occult a distant star as well.
And yes, the modern astronomical term “occultation” traces its hoary roots back to the days when astronomy was intertwined with the pseudoscience of astrology. To this day, the term still makes some folks wonder if astronomers are secretly casting horoscopes. Trust us, you’re still on a solid astronomical footing to use the term “occultation.”
Unfortunately, the January 25thoccultation of Saturn by the Moon will only grace part of Antarctica, southern Argentina and Chile, and the Falkland Islands post-sunrise. The rest of us still will see a very photogenic pass of Saturn near the waning crescent Moon on the morning of Saturday, January 25th. The Moon will pass just about a degree — two times its apparent width — south of Saturn for northern hemisphere observers.
The footprint for the January 25th occultation of Saturn by the Moon. dashed lines indicate where the events occurs in the daytime sky. (Created using Occult 4.0.11 software)
Both the Moon and Saturn will reside in the astronomical constellation of Libra this weekend during closest passage. The pair will rise around 2 AM local. After their brief tryst, the Moon will head towards New on January 30th while Saturn will continue to rise successively earlier as its heads towards opposition and the start of evening Saturn observing season on May 10th, 2014.
January 2014 is also notable for having two New Moons, an occurrence informally known as a Black Moon. This occurs again this year in March, and February 2014 is devoid of a New Moon. February is the only month that can be “missing a Moon phase” as it’s the only one shorter the synodic period of 29.5 days, in which the Moon returns to like phase.
Saturn as imaged by the author in 2012.
In the telescope, Saturn will present a +0.8 magnitude disk 16” across (38” with rings from tip-to-tip). Saturn’s rings are tipped open to our line of sight by about 22 degrees in 2014, and are widening towards a maximum of 27 degrees in 2016 through 2017. If you have an equatorial telescope with tracking capability, it may be possible this weekend to follow Saturn up into the daytime sky. Though Saturn isn’t quite bright enough to see in the daytime unaided, it might just be possible to spy using binoculars on the 25th using the nearby crescent Moon as a guide. Saturn is a tough daytime target to be sure, but it’s not impossible to acquire with a little skill and patience.
The current cycle of occultations of Saturn began on December 1st, 2013 and ends on November 22nd, 2014. The cycle will move progressively northward through the year.
The Moon and Saturn put on a repeat performance over almost the same exact location (this time in darkness) on April 17th, 2014, and the best event in the cycle for North America will be the August 31st daytime occultation of Saturn by the waxing crescent Moon.
Now for the wow factor of what you’re seeing. On Saturday morning, the Moon is just over 371,000 kilometres distant, or a little over a light second away. Saturn is over four thousand times more remote at just over 10.1 astronomical units (AUs) distant, which works out to 1.5 billion kilometres, or over 83 light minutes away. And although the Moon is over a 112 times larger in apparent diameter than Saturn as seen from the Earth, the globe of Saturn is actually over 34 times bigger.
Saturn and the Moon crossing the local meridian shortly after sunset on January 25th. Created using Starry Night Education Software.
And though we’ve been to the Moon lots since the dawn of the Space Age, only two spacecraft (Voyagers 1 and 2) have made brief flybys of the ringed world, and only one – Cassini – has orbited it. Note that China’s Chang’e-3 lander and rover are about to experience their second sunset this weekend as well from the lunar surface since landing on the Moon last month.
And although lots of planets get occulted by the Moon in 2014, no stars brighter than +1st magnitude lie in its path. In fact, the next cycle of bright star occultations by the Moon doesn’t resume until the Moon meets Aldebaran in January 29th, 2015.
There are, however, over a 100 lesser events involving the Moon occulting naked eye stars worldwide in 2014. Two such events occur this week as well, when the 48% illuminated Moon occults the +4.5th magnitude star Lambda Virginis for west-central South America on the morning of January 24th, and the occultation of the +2.8th magnitude star Alpha Librae (Zubenelgenubi) for central Asia on January 25th.
Don’t miss these celestial events, and be sure to send those pics in to Universe Today… there’s something for everyone happening in the sky this week worldwide!
Three visual athletes based in Arizona took up the challenge on Wednesday evening, with amazing results. Mike Weasner, Rob Sparks and Jim Cadien managed to spot the razor thin crescent Moon just 13 hours and 48 minutes after it passed New phase earlier on January 1st. The sighting was made using binoculars, and they even managed to image the wisp of a crescent hanging against the desert sky.
This is a difficult feat, even under the best of conditions. Weasner and Sparks observed from Mike’s Cassiopeia observatory based just outside of Oracle, Arizona.
A thin crescent Moon (arrowed) Credit: Mike Weasner/Cassiopeia observatory
Concerning the feat, Weasner wrote on his observing blog:
“At 1800 Mountain Standard Time (MST), Rob reported that he had located the young Moon using his 8×42 binoculars. At 18:02 MST, I picked it up in the 12×70 binoculars. With the New Moon occurring at 11:14 Universal Time (UT), my observation occurred with the Moon only 13 hours and 48 minutes old. A new record for me (and Rob and Jim as well). Our DSLRs were clicking away!”
We can personally attest to just how hard it is to pick out the uber-thin crescent Moon against the twilight sky. Low contrast is your enemy, making it tough to spot and even tougher to photograph. Add to that a changing twilight sky that alters hue from moment to moment.
Though this isn’t a world record, its close to within about two hours. The youngest confirmed Moon spotting using binoculars stands at 11 hours and 40 minutes accomplished by Mohsen G. Mirsaeed in Iran back in September 7th, 2002, and the youngest Moon sighted with the unaided eye goes to Steven James O’Meara in May 1990, who spotted a 15 hour 32 minute old crescent.
Jim Cadien (left) and Rob Sparks (right) setting up to catch the crescent Moon. Credit– Mike Weasner.
And of course, you can see the Moon at the moment of New during a a solar eclipse. Unfortunately, no total solar eclipses occur in 2014, just an usual non-central annular eclipse brushing Australia and Antarctica on April 29th and a deep 81% partial eclipse crossing North America on October 23rd.
Weasner also noted that a bright Venus aided them in their quest. It’s strange to think that Venus, though visually tiny, is actually intrinsically brighter than the limb of the Moon, owing to its higher albedo. In fact, some great pictures have also been pouring in to Universe Today of Venus as it heads towards inferior conjunction this month on January 11th. And don’t forget, that quoted magnitude of the lunar crescent (about magnitude -3.4) was also scattered along the lunar disk which was only 0.4% illuminated, and subject to atmospheric extinction to boot!
Our own modest attempt to catch the waning crescent Moon 29 hours prior to New back in August 2012. Photo by author.
And yes, it is possible to catch the Moon photographically during a non-eclipse at the moment of New phase. The Moon can wander up to 5 degrees – about ten times its average apparent diameter as seen from the Earth – above or below the ecliptic and appear a corresponding distance from the limb of the Sun. Unlike many moons in the solar system, Earth’s moon has a fixed inclination to our orbit (as traced out by the ecliptic,) not our rotational axis. Thierry Legault accomplished this challenging photographic feat last year. Of course, this should only be attempted by seasoned astrophotographers, as aiming a camera near the Sun is not advised.
The January 2nd 2014 waxing crescent Moon plus “Earthshine” as captured by Ron Cottrell from Oro Valley, Arizona. Ron also notes that this illumination of the nighttime side of the the Moon is also known as the “da Vinci” glow. Credit-Ron Cottrell.
Why attempt to spot the razor thin New Moon? What’s the benefit? Well, several lunar based dating systems, such as the Islamic calendar, rely on the spotting of the new crescent Moon to mark the beginning of a new month. Being strictly lunar-based, the Islamic calendar moves an average of -11 days out of sync each year versus the modern day Gregorian calendar. On some years, there can even be a bit of ambiguity as to exactly when key months such as Ramadan will begin based on when the Moon is first sighted.
Also, such a feat demonstrates what the human eye is capable of when pushed to its physiological limits. In fact, French astrophysicist Andre Danjon theorized that the lunar crescent is formed at about 5 degrees elongation from the Sun, a point beyond which a lunar crescent can be sighted — usually quoted at about 7 degrees elongation from the Sun — and has become known as the Danjon Limit. Danjon also gave his namesake to the characterization of total lunar eclipses by color and hue, known as the Danjon Number. Accounting for the motion of the Moon, this places the theoretical limit that the forming crescent can be sighted with optical assistance at just over 11 hours.
Optimal sighting locations through the end of September 2014. Positions are marked for where the Moon is visible at local sunset and becomes visible with optical assistance around 14 hours after New. Prospects for a “first sighting” get better westward of each location on the dates noted. Note that the March 1st event offers decent prospects for the US northeast and the Canadian Maritimes. Graphic created by author.
And you don’t have to wait until the Moon passes New… a similar attempt can be made in the dawn skies as the waning crescent Moon slides towards the Sun at the end of each lunation.
But perhaps the true reward is simply catching a glimpse of the ethereal for yourself, a delicate and airy Moon clinging briefly on the horizon. Kudos to Mike and Rob on a great catch!
Follow the further adventures of Mike Weasner and Rob Sparks on Twitter as @mweasner & @halfastro.
Wonder what the sighting opportunities are for the next waxing crescent Moon are worldwide? Two great online resources are the HM Nautical Office’s Einstein Moonwatch Project and Moonsighting.com.
The South African Astronomical Observatory also maintains a site with predictions worldwide.
An early Draconid meteor caught by astrophotographer Cory Schmitz. (Used with permission?)
It’s here!
As 2013 draws to a close, we once again cast our thoughts to all things astronomical for the coming year. For the past five years, I’ve been constructing this list of all things astronomical for the coming year, lovingly distilling the events transpiring worldwide down to a 101 “best events of the year”. This is the first year this list has been featured on Universe Today, so we’ll lay out our ground rules and reasoning a bit as to selection criteria.
Events selected run the gamut from conjunctions and eclipses that are visible worldwide or over a good swath of the planet, to asteroid occultations of stars that are only visible along a thin path along the surface of the Earth. Geocentric conjunction times for occultations are quoted. Generally, only conjunctions involving bright stars, planets & the Moon are noted. The intent of this list is to bridge the gap between the often meager “10 Best Astronomy Events of 2014” listicles that make their rounds this time of year and the more tedious laundry lists of Moon phases and wide conjunctions.
As always, we look at the coming year with an eye out for the astronomically curious and the bizarre. Times are quoted in Universal Time (UT) using a 24-hour clock, which is identical to Greenwich Mean Time (GMT) and Zulu for those in the military.
Some caveats as to how selections were made:
-To make the cut, asteroid occultations must have a rank of 99 or greater, and occult a star brighter than +8th magnitude.
– We only selected major annual meteor showers with a Zenithal Hourly Rate (ZHR) projected to be 20 or greater.
– Only lunar occultations of planets and bright stars are listed.
– Solstice seasons where the International Space Station reaches full illumination are approximate; the ISS gets boosted periodically, and therefore it’s impossible to project its precise orbit months in advance.
– Comets come and go. The comets included on this list are some of the “best bets” that are forcasted to reach binocular visibility for 2014. A big bright one could come up and steal the show at any time!
This list was meant to “whet the appetite” for what’s coming to skies worldwide in 2014 with a succinct rapid fire listing by month. Where an online resource exists that expands on the event, we linked to ‘em. A full resource list, both paper and cyber, is given at the end of the post. Print these events, post it on your refrigerator and/or observatory wall, and expect us to feature many these fine events on Universe Today in the coming year!
Some notes on 2014:
2014 sees Mars reach opposition in early April, which is sure to be a highlight as we head towards an exceptionally close opposition in 2018.
The month of February is also missing a New Moon, which last occurred in 1995 and won’t happen again until 2033. February is the only calendar month which can be missing the same moon phase twice!
We’re also coming off a profoundly weak solar maximum in 2014, though as always, the Sun may have some surprises in store for solar observers and aurora watchers worldwide.
The motion of the Moon in 2014 is headed towards a “shallow” year in 2015 relative to the ecliptic; it will then begin to slowly open back up and ride high around 2025.
2014 also contains the minimum number of eclipses that can occur in one year, 2 solar and 2 lunar. And while there are no total solar eclipses in 2014, there are two fine total lunar eclipses, both visible from North America.
And here’s the month by month rundown:
The view looking west from the US east coast at 6 PM on January 1st from latitude 30 degrees north. (Created in Stellarium).
03- Quadrantid meteors peak with a ZHR=120 at ~05:00 UT, best seen from the Atlantic region. Favorable in 2014, with the Moon a 2 day old waxing crescent.
04- Earth reaches perihelion at 12:00 UT, 147.1 million kilometres from the Sun.
04- Mars passes 1.3’ from the +11.5th magnitude galaxy NGC 4684.
10- A Possible meteor shower due to dust from the Comet (formerly known as) ISON over the next few days?
11- Venus reaches inferior conjunction between the Sun and the Earth, shining at -4th magnitude. It may be just possible to spot it five degrees north of the solar limb from high northern latitudes.
13- Moon reaches its farthest northern declination for 2014 a 19.4 degrees.
16- The most distant Full Moon, and visually smallest Full Moon of 2014 occurs, with the Moon reaching Full within two hours of apogee. MiniMoon!
25- The Moon occults Saturn for the South Pacific at ~13:58 UT.
27- The Moon reaches its farthest southern declination for 2014, at -19.3 degrees.
30- ABlack Moon occurs, as reckoned as the second New Moon in a month with two.
31- Mercury reaches a favorable elongation, shining at magnitude -0.9, 18.4 degrees east of the Sun.
Venus occultation footprint for February 26th. (Created using Occult v4.1.0).
February
06- Twoshadows transit the cloud tops of Jupiter from 10:20 UT-12:44 UT, favoring western North America.
21- The Moon occults Saturn for the Indian Ocean at ~22:18 UT.
26- The 14% waning crescent Moon occults Venus for central Africa at ~5:23 UT.
March
07- Asteroid 9 Metis occults a +7.9 magnitude star for Europe ~3:14 UT.
10- The 70% illuminated waxing gibbous Moon occults the +3.6 magnitude star Lambda Geminorum for North America in the evening sky.
14- Mercury reaches greatest morning elongation at 27.5 degrees west of the Sun shining at magnitude +0.1. Mercury’s best morning apparition in 2014 for southern hemisphere observers.
16- A double shadow transit of Jupiter’s moons occurs from 22:20 to 00:35 UT, visible from Atlantic Canada after sunset.
20- The Northward Equinox occurs at 16:57 UT.
20- GEO satellite eclipse season occurs, as geostationary satellites enter Earth’s shadow near the equinox.
20- Regulus is occulted by asteroid 163 Erigone for the NE United States and Canada at ~6:07 UT, The brightest star occulted by an asteroid in 2014.
21- The Moon occults Saturn for the South Atlantic at ~3:18 UT.
24- A double shadow transit of Jupiter’s moons occurs from 2:08 to 2:28 UT, favoring eastern North America.
24- Asteroid172 Baucisoccults a +6.7 magnitude star for South America at ~9:27 UT.
22- Venus reaches greatest morning elongation, at 47 degrees west of the Sun.
28- Asteroid 51 Nemausa occults a +7.7 magnitude star for Africa at 20:02 UT.
30- A Black Moon occurs, as reckoned as the second New Moon in one month.
The viewing prospects for the April 15th Total Lunar Eclipse. (Credit: NASA/GSFC/Espenak/Meeus).
April
08- Mars reaches opposition for 2014, shining at magnitude -1.5.
12- A close conjunction of Venus and Neptune occurs, with the planets just 0.7 degrees apart at 2:00 UT.
15- A Total Lunar Eclipse occurs, visible from the Americas and centered on 7:47 UT.
17- The Moon occults Saturn for South America at ~7:19 UT.
29- An Annular Solar Eclipse visible from Australia and the southern Indian Ocean occurs, centered on 6:05 UT. This is a unique, non-central antumbral eclipse!
May
03- Asteroid 105 Artemis occults a +7.7 magnitude star for NW Brazil and Peru at ~9:17 UT.
04- Asteroid 34 Circe occults a +7.4 magnitude star for Peru and Ecuador at ~10:12 UT.
06- The closest lunar apogee of 2014 occurs at 404,318 km distant at 10:23 UT.
07- Eta Aquariid meteors peak, with a ZHR=55 at 4:00 UT. Best observed from the Atlantic Region. Favorable in 2014, with the 7-day old Moon at waxing gibbous.
07- Asteroid 206 Hersilia occults a +7.5 magnitude star for Australia and Indonesia at ~17:49 UT.
10- Saturn reaches opposition for 2014, shining at magnitude +0.1. Saturn’s rings are tipped open a maximum of 23 degrees to our line of sight on February 11th, and widening overall in 2014.
13- A double shadow transit of Jupiter’s moons occurs from 9:20-9:32 UT favoring NW North America.
14- The Moon occults Saturn for Australia and New Zealand at ~12:18 UT.
24- Ameteor shower outburst may be in the offing, courtesy of Comet 209P LINEAR. Will the “Camelopardalids” perform?
24- Asteroid 33 Polyhymnia occults a +5.5 magnitude star for South America at ~8:30 UT.
25- Mercury reaches maximum dusk elongation, 22.7 degrees east of the Sun. Mercury’s best evening apparition for 2014 for northern hemisphere viewers.
The triple shadow transit of June 3rd, as seen at 19:00 UT. (Created by the author using Starry Night).
June
3- A triple Jovian shadow transit occurs from 18:05-19:44 UT, favoring eastern Europe and Africa. This is the only triple shadow transit for 2014.
10- The Moon occults Saturn for the southern Indian Ocean at ~18:48 UT.
21- The Northward Solstice occurs at ~10:51 UT.
22- The International Space Station enters a period of full illumination near the June solstice, favoring multiple views for northern hemisphere viewers.
26- The Moon occults Mercury just 20 hours prior to New… a tough catch, but may visible from the SE US and Venezuela just before sunrise.
27- The June Boötid meteors peak, with a ZHR variable from 0-100 at ~15:00 UT, favoring the Central Pacific. Optimal in 2014, as the Moon is at New phase.
July
04- Earth reaches aphelion at 2:00 UT, at 152,098,232 kilometres from the Sun.
04- Pluto reaches opposition at 3:00 UT.
05– 1 Ceres passes just 10’ from 4 Vesta in the constellation Virgo.
06– The Moon occults Mars for South America at ~01:21 UT
08– The Moon occults Saturn for Argentina & Chile at ~2:25 UT.
12- Mercury reaches its maximum elongation of 20.9 degrees west of the Sun, shining at magnitude +0.4 in the dawn.
12– The first Full Proxigean “Super” Moon (1 of 3) for 2014 occurs at 11:27 UT. The Moon reaches Full 21 hours prior to perigee.
30– The Southern Delta Aquarids peak, with a ZHR=20. Time variable, favorable in 2014 with the waxing crescent Moon 4 days past New.
20– Asteroid 451 Patientia occults a +7.1 magnitude star for South Africa at ~17:15 UT.
28- The farthest lunar apogee of 2014 occurs, with the Moon 406,568 kilometres distant at 3:28 UT.
30– Asteroid 103 Hera occults a +6.1 magnitude star for west Africa and central South America at ~1:11 UT.
A tri-conjunction of the Moon, Venus & Jupiter on the morning of August 23rd- A “Skewed Smiley face” conjunction!” Credit: Stellarium).
August
02– A close conjunction of Mercury and Jupiter occurs, with the planets just 0.9 degrees apart at 19:00 UT. Visible in SOHO’s LASCO C3 camera.
10– The closest lunar perigee of 2014 occurs, with the Moon 356,896 kilometres distant at 17:44 UT.
10- The Closest Full Moon of the year & “Super” Moon (2 of 3) for 2014 occurs, with Full Moon occurring just 27 minutes after perigee.
13– The Perseid meteors peak, with a ZHR=100 at ~04:00 UT favoring The Atlantic region. Unfavorable in 2014, with the 17 day old Moon at waning gibbous.
18- A conjunction of Venus and Jupiter occurs 5:00 UT, the closest conjunction of two naked eye planets in 2014, with the two just 15’ apart.
29- Neptune reaches opposition at 14:00 UT, shining at +7.8 magnitude.
31– The Moon occults Saturn for Africa and the eastern US (in the daytime) at ~18:59.
September
05- Venus passes 0.7 degrees from the bright star Regulus.
09– The final Full “Super” Moon (3 of 3) for 2014 occurs at 1:39 UT, just 22 hours after perigee.
15– Comet C/2013 V5 Oukaimeden may reach +5.5th magnitude for southern hemisphere observers.
20– Mercury passes 0.5 degrees south of the bright star Spica at 21:00 UT.
21- Mercury reaches its greatest elongation of 26.4 degrees east of the Sun shining at magnitude +0.0 in the dawn sky. Mercury’s best sunset apparition for 2014 for southern hemisphere observers.
23- The Southward Equinox occurs at 2:29 UT.
23- GEO satellite eclipse season occurs, as geostationary satellites enter Earth’s shadow near the equinox.
28– The Moon occults Saturn for the northern Pacific at ~4:25 UT. The Moon also occults 1 Ceres and 4 Vesta on the same day!
The path of Comet C/2013 A1 Siding Springs versus the planet Mars through October, 2014. (Created by the author using Starry Night).
October
04- 1 Ceres passes just 30’ north of Saturn.
06- PossibleDraconid meteor shower, highly variable in terms of rates and timing, but unfavorable in 2014, with the Moon just two days from Full.
08- A Total Lunar Eclipse visible from the Pacific Rim region occurs, centered on 10:56 UT. The planet Uranus will also lie less than a degree away from the eclipsed Moon!
14- Comet C/2012 K1 PanSTARRS may reach +5th magnitude for southern hemisphere viewers.
13– The Moon reaches it shallowest northern declination for 2014 at +18.5 degrees.
19- Comet C/2013 A1 Siding Spring passes just 7’ from the planet Mars. Globular cluster NGC 6401 also lies nearby.
22– The Orionid meteor shower peaks at ~05:00 UT, with a predicted ZHR=25 favoring the Americas. Optimal in 2014, with the Moon at waning crescent.
22– The Moon occults Mercury for Australia just 24 hours prior to New as seen from Australia.
23- A Partial Solar Eclipse visible from western North America occurs centered on 21:46 UT.
25- The Moon occults Saturn for the northern Atlantic at ~15:43 UT.
25- The Moon reaches its shallowest southern point for 2014, at a declination of -18.6 degrees.
The partial solar eclipse of October 23rd, 2014. (Credit: NASA/GSFC/Fred Espenak).
November
01- Mercury reaches its greatest elongation 18.7 degrees west of the Sun, shining at magnitude -0.5. The best morning apparition of Mercury for 2014 as seen from the northern hemisphere.
18– Leonid meteors peak at 05:00 UT with a ZHR=20 favoring the Atlantic region. Optimal in 2014, with the 25 day old Moon at waning crescent phase.
20- Asteroid 3 Juno occults a +7.4 magnitude star for the US NE and eastern Canada.
27- The farthest lunar perigee of 2014 occurs with the Moon 369,824 km distant at 23:12 UT.
December
09- A double shadow transit of Jupiter’s moons occurs from 4:18 to 4:27 UT favoring eastern North America.
12- A double shadow transit of Jupiter’s moons occurs from 16:19 to 16:44 UT favoring NW North America.
13- The Geminid meteors peak with a ZHR=120 at ~01:00 UT, favoring the Middle East & Eastern Europe. Unfavorable in 2014, with the 20 day old Moon at waning gibbous.
18- Asteroid 702 Alauda occults a +6.2 magnitude star at 14:12 UT for eastern Australia.
21- The Southward Solstice occurs at 23:03 UT.
21- The International Space Station enters period of full illumination around the solstice, with multiple nightly views favoring the southern hemisphere.
21- A double shadow transit of Jupiter’s moons occurs from 14:17 to 15:55 UT, favoring the Far East and Australia.
Don’t see your favorite or most anticipated event of 2014 on the list? Drop us a line and let us know!
And finally, thanks to all of those too numerous to name who provided discussions/diatribes/input via Twitter/G+/message boards/etc to make this listing possible… let another exciting year of astronomy begin!
