TALE OF TWO ECLIPSES
------------------
John Pazmino
NYSkies Astronomy Inc
www.nyskies.org
nyskies@nyskies.org
2013 October 8 initial
2013 October 16 current
Introduction
----------
By summer of 2013 astronomers in New York were getting ready for
solar eclipse of November 3rd at sunrise from the City and vicinity.
As preparations, including the October 18th NYSkies Seminar,
progressed, some of the older astronomers recalled an earlier sunrise
eclipse from New York. That was on 1959 October 2. I watched that
eclipse on my first travel from my home for an astronomy event.
Apart from the stories recounted by these elders there are several
fascinating features of the two eclipses I discuss here. For one thing
they are both members of the same Saros series, being 54 years and 31
days apart! Their global paths are almost the same, from the northeast
United States thru the middle Atlantic Ocean, thru Africa, to the
Indian Ocean.
I give a recollection of the 1959 eclipse along with an overview
of the 2013 eclipse. The report for 1959 is based on notes and
litterature of that period quite two generations ago. Some of the
information was not easily available in 1959 and was for this piece
assembled form modern sources.
Early astronomy
----------
I can't give a whole discourse on my early development in
astronomy but touch a few highlights. My first ever, eclipse I viewed
from my house on 1954.June 30.
The eclipse took place in early morning and was played up in the
news media. It was total in Canada and the Mid West. Astronomers who
later became my colleagues went to the centerline to view it. In the
City is was a large partial on the Sun's north edge.
This eclipse ignited my career in astronomy! As I viewed it thru a
stack of dense B&W negatives, assembled by my father from his
photography hobby, it freaked me out that a whole other celestial
body, the Moon, was moving across the Dun's face!
I got library books about astronomy, some by myself, others from
Manhattan libraries thru my father. I located bright stars and some
planets, like Jupiter and Mars, from the street or yard of my house.
I built simple telescopes from reading lenses, which did work well
enough to see dim stars and resolve coarse clusters. I bought a
telescope kit, consisting of just the lenses and instructions to go
and find the other parts. It worked, too, but it was long, clumsy, and
had no way to properly mount or aim it.
I joined the local astronomy club, Junior Astronomy Club (JAC),
then meeting at New York University on Manhattan. Being a city kid it
was natural to travel to its meetings by myself by train without
parents having to take me by car.
A very fortunate boost was the International Geophysical Year
(IGY) of 1957-1958, actually 18 months long. In the IGY, members of
the JAC were inducted into assorted observing programs, such as
sunspots, surorae, meteors, and, yes, tracking satellites.
A signature event of the IGY was going to be the first artificial
Earth satellite, Vanguard. The Soviet Union beat us with its Sputnik,
which I followed in the sky by binoculars. The very satellite was too
dim to see but the trailing used-up rocket was a naked-eye object.
I did one, and only one, round of duty with the Moonwatch project,
then on the former RCA building. I was a time recorder to listen to
the calls of the telescopists and write down the time from a large
clock. The event was a scramble to catch a suspected new Soviet
satellite. It was so bitterly cold and windy in the winter of 1957-
1958 that I just had to call it quits after the one instance.
In summer of 1959 I built my own astrolabe, a modern version of a
mediaeval style model. I still have it and it is called on for show-&-
tell by astronomers and historians for their talks about astrolabes.
By 1959 I had many astronomy friends from the JAC. The club was
quite unusual for being entirely operated by junior and high school
children. We kids did every thing from arranging room use at the
University to hosting speakers to editing and publishing a newsletter
to collecting and recording observations. It was not the 'junior'
section of a larger adult club or museum.
We worked with a separate club, Amateur Astronomers Association
(AAA) which consisted almost wholly of grownups. Because these were
the only two major astronomy resources in the City in the 1950s into
the 1960s the two clubs coordinated many activities, like lecture
schedules and field trips.
Alas, by 1968 the JAC dissolved under pressure of the Vietnam War
and the need for its members to get into college for the draft
deferment status. The AAA is still in business, altho its fortunes
waxed and waned over the decades.
Chasing the 1959 eclipse
----------------------
In summer of 1959 members of both AAA and JAC were preparing for
the 1959 October 2 solar eclipse. Four or five of us planned an
expedition to watch it from Canarsie pier on the north shore of
Jamaica Bay. This eclipse was the first eclipse I travelled away from
home to view.
Others in the JAC and AAA journeyed to sites near Boston, where
the eclipse was total just after sunrise. Others stayed at their homes
all over the City or found nearby sites with a low sunrise horizon.
My parents weren't happy with me being out in the owl hours to get
to Canarsie in time for sunrise! I teamed up with an other astronomer
to come to my house and then the two of us went by bus to the pier.
The other three boys went there separately.
I don't remember when we arrived at the pier. It was still night
with a bit of dawn on the horizon. The sky was clear with the Orion
group of stars in southeast. Venus, which I figured out later, was
rising almost due east.
The air was cool yet not cold and I don't recall any significant
breeze. While the sky was overall clear there was a band of shredded
cloud along the east horizon. Later,a the next meetings of JAC and AAA
I learned that this band was a cloud cover that blocked the eclipse
for Long Island and New England observers.
I never knew we could not get onto the pier. Maybe it was just too
dark to see well enough to climb safely onto it. maybe it was fenced
closed. We set up on the shore on the east side of the pier. We were
comfortable in the brightening dawn. I had my fathr's camera, tripod,
and binoculars. The others had cameras and binoculars, too, but not
regular telescopes.
We could tell that the Sun would rise behind the band of clouds
but could shine thru gaps in it. We did starspotting and waited. The
ground was too wet from the Bay to sit, forcing us to stand around.
The Canarsie site looked over the Bay, over Idelwild (now JFK)
airport and then over the Rockaways. all were low topography so the
Sun would rise over an almost pure horizon.
Eclipse circumstances
-------------------
The eclipse was not total in the City. The centerline passed north
thru Massachusetts. The middle of eclipse took place a minute or so
before sunrise in the City. When the Sun rose, it would be 95% covered
with the Moon sliding downward off of him.
The table here gives the segment of the eclipse path when the
eclipse was visible in New York City. Hours are Universal Time in the
'UT' column and Eastern Standard Time in the 'NYC' column.
'lat & long' is the location of the Moon's shadow; 'Alt Azim' is
the altitude and azimuth of the Sun at the shadow location; Durt Magn'
are the duration in minutes and magnitude in fraction of the total
phase; 'Phs' is the phase, here 'tot' for total.
'NYC' and 'Magn' are the hour and magnitude seen from New York
City. Note that before 06:56 EST the Sun didn't yet rise and after
07:45 the Moon quit the Sun at fourth contact.
SUNRISE PARTIAL SOLAR ECLIPSE, 1959 OCTOBER 2, NEW YORK
-------------------------------------------------------
UT Lat & Long Alt Azim Durt Magn Phs NYC Magn
----- -- -------- -------- ---- ---- ---- ---- ----
10:51 42.6 -72.1 0 95 0:57 1.02 tot* ----- ----
10:55 40.2 -51.3 17 109 1:25 1.02 tot 06:56 0.87
11:00 38.7 -43.6 24 116 1:39 1.02 tot 07:00 0.79
11:06 37.3 -38.0 29 120 1:50 1.03 tot 07:05 0.71
11:10 36.0 -33.7 34 125 1:59 1.03 tot 07:10 0.62
11:15 34.8 -30.0 38 128 2:08 1.03 tot 07:16 0.54
11:20 33.6 -26.8 41 132 2:16 1.03 tot 07:20 0.45
11:26 32.4 -23.9 44 136 2:23 1.03 tot 07:25 0.37
11:30 31.3 -21.4 47 139 2:29 1.03 tot 07:31 0.29
11:35 30.2 -19.1 50 143 2:35 1.03 tot 07:35 0.21
11:40 29.2 -16.9 53 147 2:41 1.03 tot 07:40 0.12
11:46 28.2 -14.9 55 151 2:45 1.03 tot 07:45 0.04
11:50 27.2 -13.0 57 156 2:50 1.03 tot ----- ----
------------------------------------------------------------
As it happened, the greatest coverage of the Sun, about 94%,
occurred with the Sun only a degree below the horizon! The Sun was
still 87% covered at sunrise. That extra couple percent gave us in
Canarsie a sight I never since heard any one else witness.
The table is built from modern computer computations. In the 1950s
the path was worked up from hand calculations and plots on paper maps.
There were discrepancies among sources for the location of the extreme
eastern, sunrise, end of the centerline was. Some had it at the east
end of Massachusetts while others had it as far west as Hudson River
in New York State. The latitude was also in question with some paths
ending in Maine and others in Buzzards Bay or Rhode Island.
In all cases we in the City saw a very large partial eclipse whose
maximum phase occurred only a minute or so before sunrise.
Dawn reversed
-----------
Dawn progressed normally as the minutes ticked off toward sunrise.
Then, a minute or so before sunrise the sky REVERSED BACK INTO
DARKNESS! The twilight 'turned around' and went back to night! Not a
full night but a darker twilight, with some stars returning to view
after being masked by dawn a moment earlier.
We freaked out. We screamed and yelled and hollered! What's going
on?!?! How can a natural effect like a dawn suddenly go backwards?!?!
Then, just as suddenly the awn came back, faster as if to 'catch
up' for lost time and the Sun broke thru a gap in the clouds! We saw
the deep incursion of the Moon in his face and got about taking
pictures. I had black & white negative film in my father's camera,
which he developed for me over the next weekend. A few pictures I
asked one of the other astronomers to hold my binoculars in front of
the camera for a magnified shot.
All pictures came out as well as can be expected under the
makeshift conditions and our excitement. I still have them! They show
the eclipsed Sun in the clouds.
At the time we didn't know how to explain the regression of the
twilight before sunrise. At later meetings we figured out that the Sun
was so deeply obscured by the Moon just before sunrise that the amount
of sunlight filling the air physicly reduced. This reduction offset
the natural increase from the Sun's approach to the horizon. With less
sunlight to light up the sir, the dawn went dark. Only when the Sun
got more exposed by the receding Moon did the dawn return to its
normal state.
Forgotten phaenomenon
------------------
We talked up our experience for several months and then moved
along to other topics at the club meetings and external dialog. On &
off over the years since then I did quick hunts for other observations
of this twilight reversal effect with no luck.
I suppose that at any eclipse when totality or a very large
maximum covering is just before sunrise observes should see the
regressed twilight. It could simply e that at later eclipses there
were no cognizant observers posted just beyond the eastern end of the
centerline. That point may always been in an inaccessible location or
maybe observers avoided it for far better locations well inside the
centerline.
I once considered that observers in New England and Long Island
saw this effect. I never found anyone who positively recognized it.
The weather over that region was fully cloudy or rainy. Any shift in
sky brightness could be camouflaged by varying density or depth of
cloud, as normally happens during any large storm. I also suspect that
facing such adverse weather many observers turned back home without
ever seeing any sky brightness effect.
Now with the coming sunrise eclipse on 2013 November 3 can there
be a possible repeat show? I don't think so. The Sun at maximum
eclipse this time is too far below the horizon, during the deep
twilight. And he is not all that much covered, only some 80%. maybe
with good photometry a dawn reversal could be detected but probably ot
by casual eye witness alone.
It may be possible from a ship positioned just on the east side of
the centerline terminus but I know of no expedition, as at early
October 2013, that's trying that observation. All land sites are too
far west, like the City, for expect any discernible effect.
I'm now in a fresh round of inquiries. DId any one see the dawn
reversal in the 1959 eclipse? If so, I want to know about it with some
substantiation like notes or diary or articles at that time.
By the geometry of the eclipse sightings could be feasible from
almost the whole length of the Hudson River. The phaenomenon could
have been stronger from the Albany area, where an actual totality
occurred in the moment before sunrise. The complete shutoff of
sunlight form the twilight could have made a full night sky 'flash'
out and then a rushed return of dawn.
Current eclipse
-------------
The eclipse of 2013 November 3 takes place at sunrise all over the
City region. The table here gives the same items as the 1959 one:
--------------------------------------------------------
SUNRISE PARTIAL SOLAR ECLIPSE, 2013 NOVEMBER 3, NEW YORK
--------------------------------------------------------
UT Lat & Long Alt Azim Durt Magn Phs NYC Magn
----- -- -------- -------- ---- ---- ---- ---- ----
11:30 17.3 -37.9 38 126 0:51 1.01 tot ----- ----
11:35 16.0 -35.2 42 128 0:57 1.01 tot 07:35 0.51
11:40 14.7 -32.9 45 130 1:03 1.01 tot 07:40 0.44
11:45 13.5 -30.8 48 132 1:08 1.01 tot 07:45 0.37
11:50 12.4 -28.8 51 135 1:13 1.01 tot 07:50 0.30
11:55 11.4 -27.0 54 137 1:18 1.01 tot 07:55 0.23
12:00 10.4 -25.3 57 140 1:22 1.01 tot 08:00 0.16
12:05 9.5 -23.7 59 143 1:26 1.01 tot 08:05 0.08
12:10 8.6 -22.1 62 147 1:30 1.02 tot 08:10 <0.01
12:15 7.8 -20.6 64 151 1:33 1.02 tot ----- ----
----------------------------------------------------------
The Moon is farther off of the Sun at sunrise than in 1959. The
duration of this eclipse in the City is only some 40 minutes from
sunrise to fourth contact. The NYC times are in EST. We leave EDST at
02h on the 3rd, a few hours before the eclipse.
Please be warned that some solar eclipse simulators report this
eclipse, and also the 159 one, is NOT visible from New York! They will
NOT display any animation or timetable for it. This is a defect in the
way the program screens eclipse by observer location.
Here is a timetable for this eclipse. The times are valid all over
NYSkies but could differ by a minute or two from other sources. Again
and again I remind, we are in Eastern Standard Time!
------------------------------------------------
PARTIAL SOLAR ECLIPSE, 2013 NOVEMBER 3, NEW YORK
------+---------------------------+-------------
EST | event | alt-az | remarks
------+---------------+--------+--------
05:24 | nautical dawn | -- --- | end of full night
05:56 | civil dawn | -- --- | start of day work
06:11 | Mercury rises | -- --- | azimuth 108 deg
06:13 | max from NYC | -4 107 | below horizon
06:29 | Sun rises | 00 109 | Moon on lower 1/2 of Sun
06:30 | Moon rises | 00 109 | on lower 1/2 of Sun
06:38 | Saturn rises | 01 111 | azimuth 108 deg
07:11 | 4th contact | 06 115 | off lower edge of Sun
07:43 | max eclipse | 12 122 | eclipse already over in NYC
------------------------------------------------------------
'Max from NYC' is for the view from New York thru a transparent
ground. This is the greatest coverage of the Sun when he is still
below the horizon.
Daylight Savings Time
-------------------
Let's get one crucial thing cleared up right now. The 2013 eclipse
takes place under EASTERN STANDARD TIME in new York! Daylight savings
time ENDS a few hours earlier, at 02h, on the very day of the eclipse!
The rule now is that daylight savings time ends on the first Sunday of
November and the 3rd, eclipse day, is that first Sunday.
You better MAKE SURE your clocks are set BACK one hour when you go
to sleep on Saturday the 2nd. If for some reason you stay up all
night, perhaps for other observing or preparation for the eclipse,
you'll witness a weird event. The clock hour 01:00=01:59 REPEATS. It
runs TWICE, first in daylight savings time and gain immediately after
in standard time! You could be horribly disoriented by this effect.
Here's a timeline for the crossover from daylight savings to
standard time on November 2-3.
------------------------------------------
--November 2-->|<--November 3-- - - -
EDST 22h----23h----00h----01h-----+ 02h EDST becomes 01h EST
|
EST 01h----02h----03h--> to eclipse
----------------------------------------------------------------
The hour 02h EDST never hits! Instantly the clock is about to
touch 02h, it snaps to 01h. The entire hour 01h-02h repeats. This
situation causes havoc in calendars and other timekeeping operations.
New York City suffered Daylight Savings Time ever since it was
resumed during World War II. Before 1967 each state, county, town made
up its own rules for the start and end of daylight savings time.
result of mindless confusion when crossing jurisdiction frontiers.
Daylight Savings Time was an artificial feature, mutable at will by
executive order or legislation in each jurisdiction.
Since the war New York started daylight savings time on the last
Sunday of April and ended it on the last Sunday of September. In 1955
it changed the rule to end on the last Sunday of October,
In New York the 1959 eclipse was under Eastern Daylight Savings
Time, but in nearby towns it could be in Eastern Standard Time.
The cockamamie system of DST was 'fixed' in 1966 by federal
regulation. Among other features, DST must start on the first Sunday
of April while the end stayed on the last Sunday of October. In 2007
the national rule was changed to the second Sunday of March and first
Sunday of November.
For all serious astronomy we simply do not bother with DST. All
times are in the standard time of the location or in Universal Time.
Only when presenting schedules and timetables for general public
enjoyment do we check for the local DST situation.
Weather
-----
November can have cloudy sky, specially around the horizon. This
happened in 1959, and we were damn lucky the clouds were shredded to
let the Sun shine thru. The weather can be awful, with snow, cold
rain, sleet, which will kill off any view of the eclipse. Dress in
full winter outfit. Try to observe at a nearby indoor shelter, like a
house or pavilion.
Solar protection
--------------
This eclipse requires full protection for solar viewing and a
clear sightline to the east and southeast horizon. The latter can be
critical being that skyline reduces both the duration and depth of
coverage of the eclipse.
If you watched the 2004 and 2012 Venus transits with proper solar
filters, they are the ones for this eclipse. Get the ready now. If you
don't have eclipse-rated filters, GET THEM NOW!!
This eclipse is total in Africa with trips already in the mill for
it. Supplies of filter may run out quickly as the eclipse approaches.
You need only low power to capture the full solar disc in the
telescope field. There's nothing much more to see under high power. In
case the Moon uncovers a sunspot or has a jagged limb, have a high
power eyepiece to hand.
Hybrid eclipse
------------
This eclipse is a 'hybrid' eclipse, meaning that it is either
total or annular, according as where you are along the centerline. In
a classical hybrid eclipse, in the middle of the shadow path, where
the bulge of Earth brings you a bit closer to the Moon, the shadow
reaches the ground. The Moon completely covers the Sun to make a total
eclipse.
Near the ends of the path the ground is farther away, by the round
shape of the globe, and the shadow falls short. The Moon is angularly
a bit smaller than the Sun and can not fully obscure him. She is
silhouetted against the solar disc to make a ring or annular eclipse.
This 2013 eclipse is a special case where the annular phase occurs
only at the starting, sunrise, end of the centerline. For the rest of
the path the eclipse is total. The Moon during her pass over the Earth
is edging closer, enough to make the shadow reach the ground at the
sunset end. She's approaching her perigee, coming on November 6.
The distance isn't all that much, only some 800 kilometers. In
fact, this eclipse is just barely annular at the sunrise end, lasting
only a few seconds because the Moon is only just barely too small to
fit over the Sun. The table here from one eclipse path computation
shows the situation at the two ends of the path. Computations near the
ends of the shadow path are sensitive to minor differences in the
input parameters of the eclipse. Take the figures here as
representative of the behavior of this eclipse.
-----------------------------------------------------
ANNULAR/TOTAL SOLAR ECLIPSE OF 2013 NOV 3, SAROS #143
CENTRAL LINE DELTA-T = 85.8 sec
U.T. Longitd Latitd Durat Altitd Width Area
HR:MN:SC DEG MN SC DEG MN SC MN:SC DEG MN KM %
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ-
11:05:00 -71 10 56 +30 26 10 00:04 +00 00 4.2 0.9988
11:07:00 -60 02 53 +26 58 15 00:08 +10 45 7.3 1.0021
11:09:00 -55 50 37 +25 26 38 00:14 +15 14 11.9 1.0034
11:11:00 -52 45 55 +24 14 35 00:18 +18 40 15.4 1.0044
11:13:00 -50 15 51 +23 12 50 00:22 +21 35 18.4 1.0052
. . . .
14:21:00 +29 55 32 +02 12 23 00:25 +19 19 20.7 1.0058
14:23:00 +32 42 11 +02 49 06 00:20 +16 00 17.4 1.0049
14:25:00 +36 19 33 +03 40 18 00:15 +11 49 13.0 1.0037
14:27:00 +42 37 54 +05 16 27 00:06 +04 51 5.7 1.0016
14:27:25 +47 15 09 +06 31 05 00:01 +00 00 0.5 1.0002
-----------------------------------------------------------
For the first couple minutes right after sunrise the obscuration,
5 of area covered, is less than one, even tho the Moon is centered on
the Sun. We got an annular eclipse lasting only a few seconds. Then,
as the ground curves toward the Moon, and the Moon descends toward
Earth, the shadow touches down and the eclipse is total then after. It
ends at local sunset as a vanishingly brief total.
I don't know of any expeditions to the sunrise end of the path to
see the annular phase. If that's what you want to do, ask the trip
operators for options.
Magnitude
-----=-
One figure of merit for an eclipse is its magnitude. The greater
this number, the more total is the eclipse. A value less than 1.00
indicates a partial or annular eclipse. Sadly as it does happen, the
explanation of this figure can be loused up badly.
The usual statement is that the magnitude of an eclipse is the
fraction of the solar diameter overlapped by the Moon. By this rule
all total eclipses have magnitude 1.00 because the entire diameter is
obscured by the Moon. Yet total eclipses have magnitudes greater than
one. An other says it's the ratio of Moon to Sun diameter. This makes
a fixed magnitude thruout the eclipse, ignoring phase and parallax
Here's the proper way to calculate an eclipse magnitude.
(ecl magn) = (Srad + Mrad - sep) / (2 * Srad)
Srad and Mrad are the angular radius of the Sun and Moon. When
diameter is given, take one half of it. Sep is the angular separation
of Sun's and Moon's centers.
The magnitude in general tables of eclipses is stated for the
geocentric observer. The figure given for a specific location on the
Earth should consider the angularly larger Moon and the separation as
modulated by parallax.
The magnitude is virtually always stated for the moment of maximum
eclipse, when the separation of Sun and Moon is the least. As the Moon
moves across the Sun the center-center separation varies to yield a
continuous gradation of the magnitude number.
The largest value of magnitude for a set of radii is a center-
over-center crossing of Moon over Sun. The separation is zero and the
formula reduces to (Srad + Mrad) / (2 * Srad). This gives the most
overrun of the Moon on the Sun.
It's possible to have zero and negative magnitude. A zero value
indicates a grazing partial eclipse. The Moon just kises the Sun at
one exterior contact on the north or south solar limb. A negative
value, which I hardly ever hear of, means the Moon misses the Sun and
does a normal New Moon phase. There is no eclipse,
The table here gives the various scenarios of eclipse magnitude
----------------
magn | scenarios
--------+----------
<0.00 + no eclipse, normal New Moon
0.00 | graze partial eclipse
<<1.00 | partial eclipse, Moon excentric from Sun
<1.00 | deep partial or annular eclipse
1.00 + graze total eclipse
>1.00 | normal total eclipse
----------------------------
A related figure is the obscuration of an eclipse. This is the
fractional area of the solar disc covered by the Moon. It is sometimes
found by squaring the magnitude but this is not the way of computing
it. You must go thru geometry of two overlapping discs of different
diameters, for Sun and Moon, based on the data used for the magnitude.
Once the Moon is fully on the Sun, in an annular or total eclipse,
the value of obscuration remains constant. It decreases when the Moon
starts to quit the Sun, exposing more of his disc.
Contacts
------
As the Moon crosses the Sun in an eclipse she touches the solar
disc at several points of tangency, where the two discs meet at a
point. From New York there is in the 2013 eclipse only one visible
tangency of the two orbs. This is the 'fourth contact' mentioned a
couple times above.
In an eclipse seen for its full duration there is a set of
contacts for each kind of eclipse. For a total eclipse they are:
---------------------------------------------
1st - first exterior tangency, eclipse begins
2nd - first interior tangency, totality begins
3rd - second interior tangency, totality ends
4th - second exterior tangency, eclipse ends
--------------------------------------------
Interior tangency hs the two orbs overlapping, the one nested
within the other. Exterior tangency hs the two orbs touched next to
each other. The Moon is invisible in the daylight around the Sun.
In a partial eclipse there are no 2nd and 3rd contacts because
there is no total phase:
---------------------------------------------
1st - first exterior tangency, eclipse begins
4th - second exterior tangency, eclipse ends
--------------------------------------------
For an annular eclipse the order of the contacts is shuffled
because the Moon does not completely cover the Sun. The trailing edge
of the Moon breaks onto the solar disc before the leading edge does.
---------------------------------------------
1st - first exterior tangency, eclipse begins
3rd - second interior tangency, annularity begins
2nd - first interior tangency, annularity ends
4th - second exterior tangency, eclipse ends
--------------------------------------------
Eclipse cycles
------------
You know about the Saros interval between eclipses of a given
series, 6585.32 days. This equals 18 Julian years plus 10.82 days. If
you by mistake treat the years as ordinary calendar years, you find
your self exactly 1/2 day too much. 18 Julian years includes 4.5
leapdays. To keep matters simpler I here absorb that 0.5 day into the
leftover days to make 10.32 days. The 1/3 day, 8 hours, spaces each
eclipse 1/3 way round the world in longitude from the previous and
following ones.
Due to our leapday system once in this cycle there is a shortfall
of one day, which is then added in as an extra item. Yes, it is a
nuisance to count up the leapdays four-by-four within a cycle.
Three Saros intervals, 54 Julian years and 30.96 days brings every
third eclipse in the series to almost the same longitude, and about
the same latitude!. The Greeks called it the exeligmos, having to do
with a wheel's rotation. It's also the Triple Saros or Long Saros.
The eclipse of 2013 November 3 is in fact the next in the current
exeligmos after the 1959 October 2! A global plot of the two eclipses
are quite similar, including the location of the western end of the
path near New York City. Both eclipse occur at sunrise in the City
with maximum coverage shortly before then.
. The maths are simple, stepping thru two intermediate eclipses
which many astronomer remember observing. I write the month as a Roman
number in the calculation here
1959 X 2.50 UT date of greatest eclipse
+18 10.32 first Saros interval
+0.00 no leapday
--------------
1977 X 12.82 1/3 way from 1959
+18 10.32 second Saros interval
+1.00 1 leapday
--------------
1995 x 24.14 2/3 way from 1959
+18 10.32 third Saros interval
+0.00 no leapday; year 2000 had a leapday
--------------
2013 X 34.46 3/3 way from, and return to, 1959
2013 XI 3.46 carry 31 days for October
I hope you remembered that year 2000 was a leapyear, yes? Else,
you inserted it as a shortfall at the last addition and now you're one
day too late in your calculation!
The last step is fiddly calendar maths. October has 31 days, which
are collected into a carried month. This leaves 3.46 days in the next
month as November 3rd..
The Saros interval does NOT give the very next eclipse to occur!
There are about 20 Saros series in progress in the decade 2010-2019,
at each point of Moon-Sun-node intercept around the ecliptic. The 1959
and 2013 eclipses are members of Saros series #143. The series are
numbered from the first entry, an eclipse of 2000 BC, in Oppolzer's
eclipse catalog 'Canon of eclipses'.
Series #143 began on 1617 March 7 with a partial eclipse at the
north pole. The eclipses of 1959, 1977, 1995. 2013 in the calculation
above are members #20 thru #23. The series ends with eclipse #71 on
2861 April 12, a partial at the south pole. The far future dating
assumes no further reform of the calendar system and ignores the
secular deceleration of Earth rotation with its leapseconds.
Because the eclipses of Saros #143 migrate from north to south,
they occur at the Moon's descending node. An ascending node series has
eclipses starting at the south pole and sifting northward.
Other eclipses
-------------
The previous solar eclipse over New York was on 2001 December 14.
The Moon first touched the Sun, 1st contact, about ten minutes before
sunset. She covered about 10% of the solar diameter at sunset.
The previous really good eclipse was on 2000 December 25,
Christmas Day! It wa a partial eclipse with the Moon covering about
1/2 of the south side of the Sun in afternoon.
The next solar eclipse for New York is on 2014 October 23, also
near sunset. The Moon again covers only 10% of the Sun's diameter.
The next good eclipse after then is on 2017 August 21. The path of
totality passes west to east across the United states, making it easy
to go into the centerline from any where in the country. If you stay
in the City, you see a 3/4 partial eclipse in afternoon.
Planets
-----
For observers in the City there are three planets in the sky
before dawn gets too bright. Mercury rises before the Sun but is lost
in bright twilight or smothered in haze along the horizon. He is dim,
only 4th magnitude, just coming out of inferior conjunction on
November 1st and has almost his complete night side facing us.
Jupiter is in high south-southwest in dawn about 1/2 between
Procyon and Pollux. He is a prime observing target among the winter
stars.
Mars is about 1/2 between Jupiter and the Sun in an equilateral
triangle with Regulus and Alphard. Hw recently came out of superior
conjunction and still has a tiny disc, making him a poor target for
detailed study.
Saturn rises after sunrise, not observable so close to the horizon
in daylight. He is +1/2 magnitude, heading toward superior conjunction
on November 19th.
If you are heading into the path ot totality, you should try to
spot the planets in the eclipse sky. Totality lasts only 1-1/2
minutes! You better study starcharts carefully to quickly look in the
proper direction without wasting precise time.
Mercury and Saturn flank the Sun for observers under totality.
Mercury is too faint for even the dark sky of totality. In my
experience stars to only 1-1/2 magnitude are the faintest to shine
thru an eclipse sky.
Mars is likely at the utter limit of detection under an eclipse
sky from his pink tint and +1-1/2 magnitude. Jupiter, much brighter
than the other planets, should come into view easily.
New York City Marathon
--------------------
November 3es is the day of the New York City Marathon! If you're
up and about for the eclipse you may go to a nearby point on the
marathon route and cheer the runners. The first wave of runners steps
off at 08:35 EST from near Fort Wadsworth, Staten Island. Following
waves step off thru 10:15.
Depending on where you are for the eclipse you may be near enough
to the route to watch the runners pass thru. Eclipses sites on the
waterfront of manhattan's Upper East Side and South Bronx are a short
walk to the marathon route.
Do understand well that in the owl thru afternoon hours there will
be massive disruption of road and foot traffic along the marathon
route. Buses will be diverted and streets will be closed. Learn the
status of traffic changes near your eclipse site BEFORE heading to it.
Investigate sites away, more than 500 meters, from the route.
Some astronomers in the City suggested to hold an eclipse session
for the marathon contestants and crew. This could be at Fort
Wadsworth, where the marathon is assembled with a prospect east and
south across New York harbor. The idea was dropped after recognizing
the extreme busyness of the marathon folk in the hours before the
race. For all practical purposes, no one in the New York City Marathon
will witness this eclipse, even if any learned of it before the race.
Government factors
----------------
November 5th, Tuesday, is the general election of mayor of New
York! While there is no specific event on eclipse day you may expect
the candidates to stage rallies here and there. Besides the mayor
contest, there are many boro and lesser citywide offices up for
election.
As at mid October there still is a partial closure of the US
Federal government. Spending authority ran out on September 30th with
no movement toward resolving the funding crisis.
If you were figuring to avail of federal property, like Gateway
national Park or a military base, please ask for its operation status.
It could be closed from public use, altho certain internal functions
may continue. It's probably best, unless the shutdown is broken real
soon, to set aside federal properties from possible eclipse viewing
locations.
Facilities dependent on federal funding could be compromised. Ask
for their status. Even after the government gets into gear, it may
take weeks or months for these collateral properties to start normal
service.
Due to the awkward hour, assuming the facility is open for you,
there could be extra redtape to go thru and tighter personal checks
before entering the facility.
Conclusion
--------
The eclipse of 2013 November 3 is far more than just the next
eclipse in the stream of astronomy events in the City. It, for the
elders among us, a physical and emotional bond to the past. Many of us
as kids watched the previous eclipse in the current exeligmos in 1959.
We wondered what it would be like far off in the 21st century. This
was when no one was thinking of a time that deep in the future. The
Y2K syndrome was unimaginable.
The whole idea of computers was still very new. Only the largest
corporations and universities had them. Information was coded into
punchcards one at a time. It was totally sci-fi that eventually we can
have a gadget orders more powerful than those machines, simpler to
use, as cheap as a transistor radio, and fit in your pocket! and it
replaces the telephone, library, and postal service!
Going to other planets was a dream for the next century. Maybe by
2000 we'll travel to the Moon. Robotic devices were monsters in the
movies, not orbiters of Saturn or rovers on Mars. Mars was criss-
crossed by canals built to conserve the polar waters. The Moon's
surface was a mystery, being either solid rock or deep dust.
Astronomy was done by hand with printed maths tables and charts and
monograms. Calculators of the day were electric desktop machines found
only in some business office and school labs. Pocket calculettes were
a fantasy of the future. Starmaps and forms were duplicated by carbon
paper, with photocopiers still rare in printing shops. Club
litterature was produced by mimeograph.
Rapid astronomy news, like for novae and comets, was issued by
real telegrams. Colleague astronomers who received the made a round of
telephone calls to us others to recite the news. To call an out-f-of-
town observatory for information, the telephone company agent had to
connect you thru. Printed material, like booklets, news items, maps,
computer printouts, were sent by postal mail.
How weird it seems today while watching this eclipse to reflect on
those ancient days! That's one of the awesome joys of astronomy. The
heavens span the ages.