SOLAR ECLIPSE IN NEW YORK, 2017 AUGUST 21 
 ---------------------------------------
 John Pazmino
 NYSkies Astronomy Inc
 www.nyskies.org
 nyskies#nyskies.org
 2017 July 28

Introduction
 ----------
    A total solar eclipse sweeps west-east across the entire 
continental United States on Monday 21 August 2017. Astronomers from 
every where in the country, and from overseas, are heading into the 
central path to observe the totality. Yet there are many astronomers 
who, for various reasons, will watch the eclipse from the NYSkies 
region as a deep partial.
    I leave out the explanation of eclipse mechanics and cycles. 
Please see my article at 

    www.nyskies.org/articles/pazmino/ecl-fact.htm 

General description 
 -----------------
    This eclipse starts in the northern Pacific Ocean at 16:49 UT, 
where the Moon's shadow first touches the Earth. There totality takes 
place at local sunrise. At 17:16 UT it hits land in Oregon, to begin 
its flight across the United States. Totality at this point is 1m 55s. 
    The shadow flies thru Oregon, Idaho,, Wyoming, Nebraska, Kansas, 
Missouri, Illinois, Kentucky. 
    At 18:26 UT the eclipse hits maximum duration near Hopkinsville, 
kentucky. Totality is 2m 40s and path width is about 145 kilometers. 
    The shadow continues thru Kentucky, Tennessee, Georgia, South 
Carolina. At Charleston, South Carolina, the Moon's shadow leaves land 
at 18:43 UT. Totality is then 2m 34s. The shadow lifts off of the 
Earth in the eastern Atlantic Ocean at 20:02 UT, where totality occurs 
at local sunset. 

Timetable of events
 ----------------- 
    The schedule here is for a midpoint on Manhattan and is valid 
thruout the NYSkies region. The eclipse occurs a minute or so earlier 
in north New Jersey; later, Long Island. The coverage is a percent or 
so less  in Metro North. It's a little more in central New Jersey. 
    Mind the altitude of the Sun, which may challenge some camera 
tripods. One trick is to mount the camera backwards. When the tripod 
is tilted down, the camera points up. 

        -----------------------------------------------
        PARTIAL SOLAR ECLIPSE, NEW YORK, 2017 AUGUST 21 
        -----------------------------------------------
        Duration 2h 38m, Obscuration 71%, Magnitude 0.768 
        ------------------------------------------------
        EDST  | event         | alt-az | remarks 
        ------+---------------+--------+--------
        06:11 | sunrise       | 00 071 | start of daylight 
        12:58 | Sun transit   | 61 180 | apparent noon 
        13:23 | 1st contact   | 60 192 | Moon enters on right 
        14:45 | mid eclipse   | 53 227 | 71% covered on bottom 
        16:01 | 4th contact   | 41 247 | Moon leaves on left 
        19:44 | sunset        | 00 289 | end of daylight 
        ----------------------------------------------

Public eclipse viewing
 --------------------
    Because the totality path is so close to NYSkies, there is an 
ongoing mass migration of astronomers into that path. Some are taking 
commercial eclipse tours while others are hopping a train, bus, plane 
to a town in the path and then scooting back home after the eclipse.
    This exodus already in late July is depleting crews of astronomy 
centers for major solar eclipse sessions. Crew is also thinned out for 
public viewing of the Perseid meteor shower, on August 11-12.
    As at late July there were NO announced eclipse, or meteor, 
sessions for the public. Sessions COULD be set up with smaller staff 
to hand, at the last minute, well after the issue of NYC Events for 
August 2017. There are several lectures about the eclipse in July and 
August, usually as a topic for a club's normal monthly meeting. 
NYSkies had its preparation session at its July 21st Seminar. 
    Please use the contacts in that, or the July, issue to inquire 
about latest news of public eclipse observing. 

Viewing location
 --------------
    There is NO special or favored site in NYSkies for watching this 
eclipse. The aspect and hour of the eclipse is substantially the same 
every where in NYSkies. 
    You may observe from home on the roof, yard, stoop. You may avail 
of any public park, field, waterfront. 
    In NYSkies all suitable locations are accessible by short drives 
by car or short rides by transit. The latter is specially welcome 
because you do not need large, heavy, bulky gear for this eclipse. 
Observing kits can be packed into a shoulder bag or wheeled luggage. 
    The one sanity check for a prospective site is the diurnal arc of 
the Sun. The eclipse begins in high south-southwest and ends in mid 
southwest. ideally the Sun should be in sight for the whole eclipse, 
about 2-1/2 hours.
    Other considerations are conveniences like refreshments and 
restrooms, refuge from sudden rain, air-condition, and general peace 
and quiet. 

 Weather 
 -----
    August in New York can be torrid and humid, with hazy skies and 
daytime showers. Temperatures can stand in the 30Cs with humidity near 
100%. Forecasts are loose, with repeated instances of wrong -- for the 
worse and the better -- predictions. 
    It is not necessary to be under the Sun for the entire eclipse. 
That will generate intense discomfort from the heat and moisture. 
Staying in shelter or shade and stepping out every five or ten minutes 
is a sensible procedure for thoro coverage of this eclipse. 
    Wear a hat to keep sun off of your head and face. Wear loose airy 
clothes. Have at ready a rain-shedder cloth to protect your eclipse 
setup in case of showers. 
    If feasible have cool water or fruit juice and unsalted finger 
snacks. Have a lawn chair with pillows

Eclpse safety 
 -----------
    I emphasize features of this eclipse pertinent to New York City 
and surrounds, where the Moon glides over the south side of the Sun in 
mid afternoon of August 21st. For starts, the Sun's face is always 
exposed, with all of his dangers to unprotected eyes. Direct viewing 
of the eclipse requires proper solar filters. 
    Please obtain these filters, even if only the cardboard spectacles 
from only astronomy sources and not undocumented vendors. There sprang 
up from the immense demand for filters a manufacture of filters that 
casually look dark enough but have no validation for eye protection. 
    Maintain custody, care, control of your eclipse rig at all times. 
Do not allow untutored people to handle it and never leave it 
unattended. When not in active use, drape a cloth over it to deter 
curious hands. The cloth also lets the rig cool off from a spell of 
solar viewing.
    Be vigilant with children who may try to stare at the Sun without 
eye protection. Eclipse glasses may fall off or be casually removed.
    Consider setting up a projection for the eclipse to satisfy a 
party or public. The image from a small scope is sent into a shaded 
area where a screen is mounted. This may be a simple white sheet of 
cardboard. 

Ambient changes 
 -------------
    In spite of the large part of the Sun's disc covered by the Moon, 
there is no casual noticeable darkening of the sky. A photometer, such 
as the light meter of a camera, will register a two or three f-stop 
dimming. A camera manually set to the normal daylight setting will 
produce darker images near mid eclipse. 
    For broken clouds or thin overcast, the changes in sky brightness 
from these clouds will completely overwhelm any effect of the Moon. 
    Near mid eclipse shadows of short straight objects are curved. 
Finger shadows look like claws. Pinhole images thru trees, grills, 
knot-holes, small punctures, are faithful replicas of the solar disc 
with the Moon over it. There could be a drop in air temperature, 
comparable to that from a thin cloud passing over the Sun. A series of 
thermometer readings taken every ten minutes, and trended on a graph 
against hour, may reveal the effect of the eclipse apart from that of 
cloud or haze. 
    There are no sky color shift from the eclipse. The quality of 
daylight remains th same thruout the eclipse. Colorations are caused 
by local weather conditions. 

Planets in the sky
 ----------------
    The brightest of the classical planets are in the sky with the Sun 
during the eclipse. Normally they are invisible in daylight. Venus is 
about 34 degrees west of the Sun along the ecliptic; Jupiter, 51 
degrees east.
    With sharp vision and knowing just where to look many people can 
spot Venus by day. A very few can also find Jupiter. If near mid 
eclipse the sky is truly clear, a deep blue with temperatures in the 
10Cs and wind sweeping thru the air, you may try to find Venus and 
Jupiter with binoculars.  Altho you will not notice a significant sky 
darkening from the eclipse, the sky is about 1/4 of its full daytime 
brightness, giving the planets a darker background. 
    First carefully focus the binoculars on distant landscape, order 
at least 1/2 kilometer away. Then look over the landscape where the 
planets are, as worked out with you planetarium software and 
familiarity with the observing site. The alt-az of both planets at 
14:45 EDST is: 

        ------------------
        planet  | elon | alt-az 
        --------+------+-------
        Venus   | 34 W | 35 268  
        Jupiter | 51 E | 39 153 
        -----------------------

    The planets travel along their own diurnal arcs, 
    Spot these positions over your landscape in the dys before the 
eclipse while mapping your site. Both planets follow their own diurnal 
paths thru the sky, which you must trace out with the software for 
other times during the eclipse. 
    Sit in a comfortable chair. Don't try this experiment standing up. 
You'll quickly tire and lose aim. Let the eyes relax. Check the focus 
on remote landscape. 
    Venus should show up as a white pinpoint; Jupiter, a yellowish 
one.  After the eclipse Jupiter will be in high south. If you can, 
inspect it with a telescope. You'll be surprised how textured and 
colorful it is! 
    For hazy or thinly clouded sky, the planets are oblitterated from 
view.  Mars and Mercury are also in the sky nearer to the Sun but they 
are not reasonably visible in daylight. 

Photography
 ---------
    Cameras and other imaging devices must be protected by front-end 
solar filters. Let the camera find the exposure in 'auto' mode. Any 
deficiency of image quality can be fixed in an image editor software.
    A montage sequence of the eclipse is easiest made by pasting 
separate images into a new blank image in the editor. Only the higher 
end cameras allow double-exposure, the feature used in film 
photography for an eclipse sequence. 
    One concern in the last ten years is the wholesale migration of 
photography from chemical film to electronics. Many devices are 
sensitive to near and mid infrared as well as to optical wavelengths. 
It is possible, but I don't know for sure, that filters for newer 
imagining devices COULD transmit these infrared band. If so, these 
filters CAN NOT be used for viewing by eye.They are ONLY for the 
picture-taking instrument 

Grand Central Terminal
 --------------------
    The eclipse occurs on Manhattan during the hours the Sun shines in 
line with park Avenue in early-mid afternoon. The Sun passes thru 
grilled borders of windows in the Terminal and throws sun splashes on 
the floor of the Main Concourse. Normally these are round and attract 
almost no notice from the hundreds of thousands of daily visitors in 
the depot. 
    During the eclipse these splashes, genuine pinhole images of the 
solar disc, replicate the Moon's passage across the solar disc. The 
long throw from the high windows to the floor is tens of meters, 
making the Sun's image some 20 cm in diameter. 
    Make a smooth white stiff card, like from a gift box, about 184 
meter square. Bring it to the Terminal at 13:00 EDST.  Arriving early 
lets you find a convenient sharp splash. Hold the card face-on to the 
sun's rays. 
    Make sure you pick a splash from the south windows, facing 42nd 
Street, and NOT reflections off of the Met Life building on the north. 
Splashes from the latter are distorted. 
    Clouds that may come over the Sun show up well, as will any large 
sunspots.  With your back to the Sun the Moon enters the solar disc 
from the right. It then passes over the upper part of the Sun  and 
leaves at the left. 
    You may have to skip to an other splash if the first one is 
blocked off by a structure in the Concourse. By around 15:30 EDST the 
Sun moves behind buildings on the west side of Park Av, ending its 
creation of splashes. 
    NOTATE MAGIS BENE!! There is NO official program for eclipse 
watching inside the Terminal!. You merely stand away from people flow 
and rake occasional looks at the image on your card. Other people will 
ask what you are doing, leading to a knock-off dialog of the eclipse. 
Just avoid blocking or impeding traffic flow as people surge hither 
thither around the Concourse. 

other solar eclipses 
 ------------------
    The next solar eclipse for NYSkies is on 2021 June 10. This 
eclipse requires a clear northeast horizon because the Sun  rises 
almost exactly at mid eclipse! The Moon covers most of the left side 
of the solar disc. Then after as the Sun arcs higher the Moon slides 
off at the bottom. 
    The eclipse is annular in its central path in Canada and 
Greenland. The Moon is too small to fully cover the Sun. 
    The table below from NASA's eclipse web lists recent and near 
future solar eclipses visible from New York. 
    All of the eclipses are partials because their central paths miss 
New York or there is no central path. 
    In this table all hours are EST, ignoring the summer shift to 
EDST. 'S' against an hour is the time of local sunset. The eclipse 
continues after sunset. A 'R' means the time is for sunrise. The 
eclipse begins before sunrise. 

 ------------------------------------------------------------
 local date    type  begin  max    end    alt-az  magn   obsc 
 ------------  ----   ----  -----  -----  ------  ------ -----
  2001 Dec 14  Annr  16:13  16:26S 16:26S 00 239  0.123  0.050    
  2013 Nov 03  Hybr  06:32R 06:32R 07:11  00 110  0.557  0.455   
  2014 Oct 23  Part  16:49  17:01S 17:01S 00 255  0.140  0.060    
  2017 Aug 21  Totl  12:23  13:45  15:01  53 226  0.770  0.716    
  2021 Jun 10  Annr  04:28R 04:33  05:31  01 059  0.797  0.725    
  2023 Oct 14  Annr  11:09  12:22  13:36  40 193  0.349  0.230    
  2024 Apr 08  Totl  13:10  14:25  15:36  43 235  0.911  0.900    
  2025 Mar 29  Part  05:47R 05:47R 06:05  00  85  0.326  0.214    
 ------------------------------------------------------------

Conclusion
 -------- 
    This August 21 eclipse is a wonderful event, even if you are in 
town, away from the totality path. It demonstrates celestial mechanics 
and causes some interesting effects around you. it prepares ou for the 
partial phases of a future total eclipse you may travel to. 
    As long as the Sun is visible, not completely hidden by solid 
clouds, you should make all effort to watch the eclipse. Even passing 
clouds do not hurt the view because there is no critical instant that 
must be witnessed or else.
    When your fellow astronomers return from the totality zone, thru 
will appreciate your experience with this eclipse, as told at the 
'eclipse roundup' club meeting.