About the Recent Lunar Eclipse

By the Dark of the Moon …

… indeed the last eclipse was darker than most — but not as dark as I had hoped for.

From Spaceweather.com:

“LUNAR ECLIPSE DETECTS GLOBAL COOLING (BUT ONLY A LITTLE): On Sept. 27th, people on five continents watched the Moon pass through the shadow of our planet. Most agreed that the lunar eclipse was darker than usual. Little did they know, they were witnessing a sign of global cooling. But only a little.

Above: “The eclipse was truly dark,” says photographer Giuseppe Petricca of Pisa, Italy

Atmospheric scientist Richard Keen of the University of Colorado explains: “Lunar eclipses tell us a lot about the transparency of Earth’s atmosphere. When the stratosphere is clogged with volcanic ash and other aerosols, lunar eclipses tend to be dark red. On the other hand, when the stratosphere is relatively clear, lunar eclipses are bright orange.”

This is important because the stratosphere affects climate; a clear stratosphere ‘lets the sunshine in’ to warm the Earth below. At a 2008 SORCE conference Keen reported that “The lunar eclipse record indicates a clear stratosphere over the past decade, and that this has contributed about 0.2 degrees to recent warming.”

The eclipse of Sept. 27, 2015, however, was not as bright as recent eclipses. Trained observers in 7 countries estimated that the eclipse was about 0.4 magnitude dimmer than expected, a brightness reduction of about 33 percent.

What happened? “There is a layer of volcanic aerosols in the lower stratosphere,” says Steve Albers of NOAA. “It comes from Chile’s Calbuco volcano, which erupted in April 2015. Six months later, we are still seeing the effects of this material on sunsets in both hemispheres–and it appears to have affected the eclipse as well.”

Volcanic dust in the stratosphere tends to reflect sunlight, thus cooling the Earth below. “In terms of climate, Calbuco’s optical thickness of 0.01 corresponds to a ‘climate forcing’ of 0.2 Watts/m2, or a global cooling of 0.04 degrees C,” says Keen, who emphasizes that this is a very small amount of cooling. For comparison, the eruption of Pinatubo in 1991 produced 0.6 C of cooling and rare July snows at Keen’s mountain home in Colorado.

“I do not anticipate a ‘year without a summer’ from this one!” he says. “It will probably be completely overwhelmed by the warming effects of El Nino now under way in the Pacific.”

This lunar eclipse has allowed Keen measure the smallest amount of volcanic exhaust, and the smallest amount of resultant “global cooling” of all his measurements to date. And that is saying something considering that he has been monitoring lunar eclipses for decades.

“This is indeed the smallest volcanic eruption I’ve ever detected,” says Keen. “It gives me a better idea of the detection capabilities of the system (eclipses plus human observers), so when I go back into the 1800s I can hope to find similarly smallish eruptions in the historical record.”

Paul Davis

Star Calendar – October 2015

Star Calendar

October 2015

Star Calendar Planets:

Moon moves through the stars, eastward, at its own diameter every hour, or, 13 degrees per day, or, one season per week — as noted below.

Mercury is pretty bright now and is at greatest elongation mid-month. Those with a clear view to the east might pick him out due east at about 5:00AM

Venus is in her afterglow after her maximum brilliance last month. She is still at a large angle from the Sun and can be seen during the daytime with a little care. Look about 45 degrees (half a right angle) ahead of (right of) the Sun and patiently let the eyes linger, wandering in slowly larger circles around the chosen spot in the sky. Don’t look too hard or dart around too much. Once you see Venus you’ll wonder why it seemed so impossibly invisible to begin with — it just stands there sharp and bright; but if you go out another time it’s just as hard to find again!

Sun no longer gets high enough in our sky to create Vitamin D in our skin. The rule of thumb is that if your shadow is longer than you are tall, you are not getting the rays that stimulate that beneficial nutrient. The native northern-clime peoples make up for this with a very fatty acid (fish oil) diet. Those that shower daily might consider skipping the soap unless it’s actually needed; Vitamin D is an oil kept in your skin and it washes off with soap! UVA lights will give a suntan — but it is UVB or UVC that is needed to make Vitamin D.

Mars should now be visible, east in morning nautical twilight (around 5:00AM). As October opens he will be below Regulus and slightly dimmer. Venus stands higher, very bright, and Jupiter below, quite bright as well. On the 9th the Moon will stand just to the right; on the 18th Jupiter will stand very close by and he will finally have a sojourn with Venus on Nov.2nd.

Jupiter is the brightest object beneath Venus in the morning.

Saturn is low in the SW these evenings. He shuffles into Scorpius on the 16th, accompanied over the threshold by a crescent young Moon that night. They are SW at about 6:00PM

Star Calendar Dates:

1      Sunrise/sunset in Spring Valley at 6:53/18:38 EDT (11h45m daylight)

2      Moon near Aldebaran high in SW at 5:00AM

3      Moonrise most north-of-east for month, at 10:15PM

8      Moon above Venus, beside Regulus in east at 5:00AM

          Mars above Jupiter, a little lower in the east

          Mercury stationary to retrograde

9      Moon beside Mars, above Jupiter in east at 5:00AM

          Draconid meteors (?) from overhead in late evening

11      Moon rises due east, thin and very low, to right of Mercury at around 5:AM

12      Uranus in opposition, up all night in Pisces, (for binoculars)

14      Islamic year 1437 A.H. begins at sundown

15      Mercury at greatest elongation, visible in morning nautical twilight low in east

16      Moon above Saturn in WSW at 6:15 PM, both in Scorpius, near Antares

18      Jupiter to right of much dimmer Mars (both below Venus) in east at 5:AM

          Moonrise most south-of-east for month, at 11:15AM

24-25 Standard Time resumes in Europe

          Moon rises due east at 3:30PM

25      Venus to right of much less bright Jupiter in east at 5:00AM

26      Venus at greatest elongation, largest angle from Sun

27      Full Hunter’s Moon 8:05AM

29      Moon rises below Aldebaran, ENE at 8:00PM

31      Sunrise/sunset in Spring Valley at 7:26/17:53 EDT (10h27m daylight)

          Waning gibbous Moon rises 3 hours after darkness falls on Halloween

          Moon rises most north-of-east again, just before 9:00PM

Star Calendar – September, 2015

Star Calendar

September 2015

Star Calendar Planets:

Moon will be waning as September opens and the ecliptic especially steep to the horizon in the morning. This circumstance will show especially thin and horizontal crescents on the 11/12th. New Moon begins the Hebrew new year (Rosh Hashanah) 5776 Anno Mundi. Moon’s ascending node currently lies where the Sun stands on the 24th, making this month an eclipse season. On the 13th the New Moon will be at an extreme apogee and its shadow will not reach the earth; a partial solar eclipse (for those near South Africa and the proximate part of Antarctica). However the Full and most perigee Moon of the 27–28th may well yield an especially dark lunar eclipse. A dark Moon is hard to see and is much more creepy than a red/yellow one; it looks like a giant stone hanging in the sky.

Mercury makes a large angle from the evening Sun on the 4th — but suffers from a shallow ecliptic. One may catch a peek around then, low in the west at 8PM. Mercury begins retrograde motion on the 17 and crosses the nearside of the Sun on the 30th.

Venus brightens to a maximum magnitude (for the year) of -4.8 on the 20th. She is receding from us and waxing in phase but is brightest while still crescent. The angular area Venus occupies in the sky diminishes as she recedes, that area being maximal on the 21st — when the waxing phase briefly overtakes the diminishing of receding distance.

Sun crosses the celestial equator on the 23rd, its center crossing at 4:21AM. The day of equinox is still 3 minutes longer than night though, a 12-hour-night waits for the 25/26th. Success in balancing eggs on their ends at equinox only indicates a greater patience and diligence in the attempt. There is no special gravity or balance-energy that day. Sorry.

Mars defers to Venus these mornings and passes (slightly dimmer than and) close to Regulus on the 25th, while bracketed by Venus above, Jupiter below.

Jupiter will be noticed emerging from his sunbath some fine morning this month, appearing below and much brighter than Regulus in the east. Weather and horizon permitting, look for it while scouting for old crescent Moons in the east at 6AM on the 11/12th.

Saturn is in the lower SW in the evening, and is the brightest celestial object in the vicinity. The Moon will be nearby on the 18th. Continue reading

Star Calendar – August 2015

Star Calendar

August 2015

Star Calendar Planets:

Moon will now be Full near the ends of the months for a while. This month will have two occasions of perigee occurring within 24 hours of syzygy; look for Spring Tide inundations on the 1st and 30th. New Moon is timed for ideal Perseid meteor viewing this year. I plan to look for them (from Breezy Hill, Springfield, VT) during the 80th “Stellafane” convention. RIP Carl Breuning (I’ll never forget viewing Mars with the 12” Porter Turret; sharp and clear through solid cloud-cover – this surprised us both!).

Mercury slips into the evening sky as Venus departs. On the 6th and 7th, in the glare of evening twilight, there is a close tussle with Jupiter and Regulus but we may hope for a better view on the 16th, to the right of a standing crescent Moon.

Venus takes a bow and swiftly crosses the nearside of the Sun this month. Look for a liaison with Mars, beginning as the Full Moon sets on the morning of the 29th with RA conjunction, but more pleasing to the eye in the first week of September.

Sun is halfway from solstice to equinox on the 1st; “Lammas” (Loaf-Mass) is a cross-quarter harvest festival.

Mars will creep into view for early risers during the middle of this month. Diehards might look to the left of the crescent Moon at 4-4:15 AM on the 13th. Mars will then appear in line with and below Gemini’s Pollux and Castor.

Jupiter takes a passage behind the Sun, conjunct on the 26th.

Saturn finishes a long retrograde period on the 2nd and is at quadrature (90 degrees from Sun) on the 21st. Saturn is now strictly an “evening star” as it sets before midnight and appears in the evening beyond culmination.

Pluto: the latest astronomical centerfold, and an intriguing one it is. The space-camera is traveling at truly meteoric speed. Consider: my 33-yr-old car has traveled about 400,000 miles, or just over 2 light-seconds (“to the Moon” – and nearly back); Pluto (near the Teapot) is about 5½ light-hours away, or 9,900 times that distance. Continue reading

Star Calendar – July, 2015

Star Calendar

July 2015

Star Calendar Planets:

Moon is Full at both ends of this month; but most comely when a companion young crescent around the 18th.

Mercury slips behind the Sun on the 23rd. Our next chance to see Mercury may come August 16th, beside a crescent Moon.

Venus now approaches us in earnest and her disk is greatly increasing in size. At the same time she is showing us less of her disk as she wanes in phase. The visible (lighted) part of Venus covers the greatest angular area of our sky as she sets on the 9th, but she continues to brighten to a maximum on the 12th. Venus and Jupiter make the closest of three encounters on the 1st, separated by only 4/10 degree as the evening darkens. Their second (RA)* conjunction is less sensational at 6 degrees on the 31st, and the third will come on October 26th – that being a morning apparition.

Sun has appeared for half the number of days for our calendar year at noon on the 1st, but does not progress halfway round the ecliptic until the next day. The discrepancy may seem odd at first but makes sense when we consider that its progress is most rapid when nearer than average (Fall to Spring) and tardier when farther away (Spring to Fall). If the calendar year were to begin at spring equinox instead, we would be halfway through the calendar on Sept 19th, but the Sun would take another 5 days to reach halfway along the ecliptic. Put another way, the time between equinoxes are 186 ½ and 178 ¾ days respectively; between solstices 181 ¾ and 183 ½. The Sun does NOT run like clockwork!

Mars is on summer vacation.

Jupiter, encouraged by a kiss from Venus, continues his quest for Regulus. The evenings of the 17th, 18th and 19th offer especially picturesque arrangements of Crescent Moon, Crescent Venus, Jupiter and Regulus; don’t miss them.

Saturn culminates (is highest, in the south, at about 9:PM) just as it gets dark this month and shines now at the same brilliance as the brightest of our summer stars, Vega. Vega is to be seen then in the east, to the left of Saturn.

*RA, R.A. or Right Ascension refers to a sky coordinate system based on the celestial equator divided into 24 sections. It is the component of distance along the equator to the left of the vernal equinoctal point and is given in units of hours, minutes and seconds where 0h is vernal equinox point. The other component is degrees Declination, which is the distance above or below the equator (+/- 90). For example, the summer solstice point is at 6h, +23.5 degrees. Conjunctions are usually (but not always) considered to be when the RA of two objects are the same.

 Star Calendar Days:

1      Sunrise/sunset in Spring Valley at 5:27/20:33 EDT (15h6m daylight)

          Halfway through AD 2015 at lunchtime

          Venus and Jupiter in nearest of triple conjunction, .4 degrees apart

          Full Thunder Moon 10:20PM

2      Sun opposite its Jan.1st position on the ecliptic

6      Sun most distant for the year, 3% farther than in January; moves most slowly

9      Venus illuminates largest area of sky

12      Moon near Aldebaran predawn in east

          Venus brightest for this appearance, -4.7 mag.

16      Moon, Venus and Regulus within smallest circle, West at 9:PM

17-19 Moon, Venus, Jupiter and Regulus gather each evening in West

22-23 Moon passes Spica, SW after 9: each evening

23      Venus stationary to stars, begins retrograde motion

          Mercury at superior conjunction, crosses behind Sun

25      Moon approaches Saturn (from the right) SSW after 9:PM

26      Moon above Antares, Saturn to right, S – SSW after 9:PM

31      Sunrise/sunset in Spring Valley at 5:51/20:14 EDT (14h23m daylight)

          Full Hay Moon 6:43AM

          Venus and Jupiter are conjunct (same R.A.) again, 6 degrees apart

Star Calendar – June, 2015

Star Calendar

June 2015

Star Calendar Planets:

Moon opens the month large in phase and casting long shadows – sometimes being completely obscured by foliage and other horizon clutter. The low-running Full Moon of June contrasts with the height of the Sun. Harken back to the December Full Moon that runs so high, so long, and casts short shadows.

Mercury resumes direct motion against the stars on the 11th and makes a feeble but improving morning appearance at an inconveniently early hour. Although its greatest angle from the Sun occurs on the 24th, circumstances improve after this as the trailing ecliptic makes a steeper cut against the horizon towards July. The determined, stalwart observer with an excellent view to the ENE, might begin looking on the 27th – at about 3:15 AM.

Venus continues to brighten and achieves 1/8 of a circle angular distance from the evening Sun. Even though her phase diminishes she continues to brighten because she gets so much closer (larger angular area) to us. The month opens with an alignment with the heads of the Twins, culminates with a series of stunning triangles with Jupiter and the Moon, and closes with a striking close encounter with Jupiter.

Sun reaches its maximum distance from the celestial equator (declination) during lunch on the 21st and then begins to descend toward the equator again. The moment of transition is called the solstice or “Sun-standing”. Astronomically this is the mid-point of summer. Weather-wise, like with your frypan, the midpoint of the cycle of heating and cooling lags behind the application of flame. Our summer weather is largely hangover heat. Continue reading

Star Calendar – May, 2015

Star Calendar

May 2015

Star Calendar Planets:

Moon marks the vernal equinox point as it rises 4-5 AM as a waning crescent on the 14th. On the 20th the Moon crosses the summer colure (but somewhat below the ecliptic) and one can then see/feel how far it is to summer after sunset on that evening. On the 27th the Moon sits just about exactly on the fall equinox after sunset.

Mercury is highest for this evening appearance on the 7th, but is also already getting dimmer. He is stationary to stars, beginning retrograde motion, on the 19th and in only 8 days overtakes Mars in their race toward the Sun. Mercury crosses in front of Sun on the 30th and will make a poor morning appearance in June.

Venus continues to be seen slightly higher and brighter each evening this month. The Moon makes a nice enhancement on the 21st as she approaches a fetching alignment with Pollux and Castor of Gemini – coming in early June.

Sun movement along the ecliptic is slowing down, bringing meridian crossings (solar noons) closer together (shortening the interval of the whole day). At the same time there is an increasing advancement of the Sun’s equatorial-coordinate movement each day (lengthening the whole day interval). The latter factor overtakes the former in magnitude on the 14th of this month – see Equation of Time below. It is odd that the cross-quarter of the seasons (here, the midpoint between vernal equinox and summer solstice, on April 30) just about coincides with the 1/3 point of our Roman calendar year, on May 1.

Mars (unobservably) approaches the Sun with stealth and will creep around and behind in mid-June.

Jupiter stands halfway to the zenith in the WSW after sunset. To the left, and somewhat higher, is Regulus, the heart of Leo. The pair will slowly converge and appear lower each evening – their accomplished meeting in August then being obscured by proximity to the Sun.

Saturn is in opposition and up all night, rising below the much higher Arcturus in the evening. Saturn, now at maximum brightness, just about reaches “zero magnitude”, which is defined as the brightness of the star Vega (to be seen further to the NE these evenings). Vega is the brightest star of our summer sky. Continue reading

Star Calendar – April, 2015

Star Calendar

April 2015

Star Calendar Planets:

Moon and Sun cycles interacting generate the modern (Mainmonedesian) “lunisolar” Hebrew calendar. The calendar day begins just after evening civil twilight with the light and dark portions each then being divided into 12 hours. The month begins with the evening following New Moon. On seven occasions within a 19-year cycle of years an extra (intercalary) month is inserted to keep the normal months aligned with the seasonal solar year so that the year begins with the New Moon placed such that the following Full Moon (Nisan 15) occurs on or after the spring equinox. That Full Moon begins the seven days of Pesach or Passover. In the Gospels of Matthew, Mark and Luke, the Last Supper takes place at the beginning of Friday (! – n.b. EVENING begins the day!) Nisan 15. The crucifixion occurs during the following daylight hours (Good Friday) and Easter is the next Sunday. Various attempts to be faithful to, or emancipated from, various historical and/or astronomical aspects, or to regularize dates, have caused enormous complexities in defining the date of Easter. The fact is that Easter is a unique event – its historical/astronomical circumstances simply do not recur. So we might simply commemorate its spirit. Eastern churches use a 19-cycle formula for Paschal Moons, from Nicaea AD 325, to fix the date of Easter on the Julian Calendar. Western churches have gradually moved to the Gregorian Calendar, since AD 1583, and have an 84-cycle formula. Even when the two Easters occur on the same day – they’re still on different dates! Note that even a purely astronomical definition of Passover or Easter is troublesome since, due to time zones, world-wide astronomical events occur on two dates simultaneously!

Mercury crosses behind the Sun during the night of the 9th-10th.

Venus passes the Pleiades (aka “seven sisters”, one of which is called “Subaru” in Japan) during the second week of this month. Look west each evening between about 8:30 and 9PM.

Sun gave us a surprise wallop mid-March; resulting in some radio disturbances and intense Aurora.

Mars begins a three-month hiatus in the middle of this month and will reappear by mid-August.

Jupiter resumes direct (leftwards) motion amongst the stars on the 8th and begins to head for Regulus again. He will cross into the realm of Leo in early June and reach Regulus in August.

Saturn is now retrograde and will find its opposition in May. Saturn brightens much less dramatically than Jupiter. Continue reading

Star Calendar – March, 2015

Star Calendar

March 2015

Star Calendar Planets:

Moon casts a perigee-large shadow on the earth, a total solar eclipse, just as the spring Sun rises at the north pole – after a 6-month night. Technically it is a near-miss – but the fact of atmospheric refraction makes the apparent, observable sun rise earlier than it would in a vacuum. It is during this smeared image of the Sun that a “green flash” can occur – it would be interesting to look for this phenomenon with the altered, diminished and very slowly rising Sun near totality. Will anyone trek to the polar regions for this? The path of total eclipse first traverses the mid-Atlantic on a northward track that crosses the Faeroes and Svalbard before terminating at the North Pole. A large region of partial eclipse will cross much of the Atlantic, Greenland, North Africa, Europe and Siberia. The eclipse will end at both sunrise and sunset for areas either side of the pole!

Mercury is too low in the morning to see. A tall, standing crescent Moon will rise (probably not visible either) to his left on the 19th at 6:30AM

Venus pulls away from Mars and slowly ascends with each evening appearance. A young crescent Moon will sit beside her on the evening of the 22nd.

Sun still malingers weak in spots as February closed. There remain indications of a future prolonged period of low sunspot activity – that is, there is a paucity of the usual indicator of future sunspots in polar gestation. Oh yes, and it’s SPRING! I expect our botanical spring to be rapid since the ground is already thawed out under the thick snow.

Mars is slowly losing ground to the overtaking Sun in the evening. He hosts a beautiful Grail Moon (the young, cup-like crescent that appears before Easter) on the 21st.

Jupiter is now recovering in “post-op(position)”. He remains the compliment to Venus in the evenings, holding forth in the east while she dominates the west. The Moon appears nearby twice this month, on the nights of the 2nd/3rd and the 29th/30th.

Saturn is so astonished at the calendar, when it happens to read like 5 digits of Pi (in MM/DD/YY format), that he stands still (stationary to stars) on the 14th, and begins to move backward (retrograde). Saturn rises awkwardly late these days, around midnight, and has a dawdling culmination in morning twilight, low in the deep-winter region of Scorpio. Continue reading

Star Calendar – February 2015

Star Calendar

February 2015

Star Calendar Planets:

Moon is innocuously Full at a safe distance, but will be New only a few hours from perigee.

Mercury makes a feeble morning apparition this month and may be seen with the aid of the Moon on the 17th. Subsequent mornings will find Mercury by itself low in the ESE, somewhat below and to the right of brighter Altair.

Venus had a subtle meeting with Mercury last month. This month, chaperoned by the Moon, she meets very publicly with Mars on the equinoctial point on the 20th-21st.

Sun gives us noticeably longer days over the course of this month – by the end of February the sky is light 12 hours a day if one includes the bright sky of civil twilight. According to the Sun’s progress through the zodiac we are halfway to equinox on the 2nd, “Groundhog Day”, but according to the culminating height of the Sun, or, of the change in the length of daylight, the midpoint is on the 18th.

Mars meets the brilliant Venus this month, as mentioned above, and appears a little lower each evening. Mars is nevertheless progressing leftwards though, and crosses the vernal equinox point – staying above the equator now until November.

Jupiter is in opposition on the 6th. On the night of the 3rd – 4th the Full Moon will be nearby.

Saturn is more toward the south now at a reasonable pre-dawn hour. The Moon will be near on the 12th and 13th.

Comet Lovejoy has been a delight to watch as it passed the Pleiades in late January. Once found with binoculars it was easily discernible without them. February 5th, 6th, before the gibbous Moon rises, may afford a last glimpse before it fades away. Look in the evening, West, above the diamond of Pegasus and to the left of the “W” of Cassiopeia. Continue reading