2012 TRANSIT OF VENUS IN NEW YORK
-------------------------------
John Pazmino
NYSkies Astronomy Inc
www.nyskies.org
nyskies@nyskies.org
2012 April 29 initial
2012 May 29 current
Introduction
----------
This article discusses the Venus transit of 2012 June 5 from New
York City and surrounds. It gives the significant information to
organize your observing but skips most of the historical and technical
aspects of the event. The transit is already a substantial portion of
litterature, in print and online. Much is an accumulation onto the
material issued for the 2004 transit.
There is no similar page here for the 2004 transit because it
preceded the NYSkies website. Information about that transit was
disseminated to City astronomers thru the NYSkies yahoogroup and
takeaways at various astronomy meetings around the City.
Many facts & figures here are adapted from other astronomy sources
while others come from my calculations or simulations via computer
astronomy programs. Much of the advice here is similar to that for
viewing the Stonehenge sunset on Manhattan. The transit and Stonehenge
occur a few days apart under about the same regime of weather and
summer conditions.
June 5th or 6th?
--------------
Understand well that in New York, and all of the Western
Hemisphere, the transit occurs on June 5th and NOT on the 6th. This is
due to two causes. The first is that the middle of transit, for which
the time of occurrence is typicly cited, does fall on the 6th. The
event spans about six hours, from the late hours of June 5th and early
hours of June 6th n Universal Time. The start of the transit is at
about 22:05 UT on June 5th
The other reason is a timezone shift. New York time is four hours
behind Universal Time. That is four, and not five, due to Daylight
Savings Time prevailing during the transit. The beginning of the
transit in New York is near 18:05 on June 5th.
This table shows the times of the transit in UT and EDST. UT is
also known as GMT. All hours here are geocentric.
------------------------------------------
location | zone | contact I | middle | contact IV
----------+------+-----------+-----------+-----------
Greenwich | UT | 22:09 5th | 01:29 6th | 04:49 6th
New York | EDST | 18:09 5th | 21:29 5th | 00:49 6th
----------------------------------------------------
The confusing region of the world is the Pacific Ocean, where the
transit if visible from start to end in midday. The hours span the
International Date Line. Observers west of IDL see it on June 6th and
those east of IDL see it on June 5th!
Viewing site
----------
There is no special location in and around the City to view the
transit. Like for a lunar eclipse, any place that offers a clear line
of sight to the Sun is quite good enough. Because the transit
continues thru sunset, the prime factor to look for is a low
northwestern horizon around the summer sunset point.
A high skyline will shorten the duration and extent of the event,
which continues out of sight behind such obstructions. Elevation to
look over foreground skyline; waterfront looking over large waters are
the two principal types of viewing site for a view of Venus.on the
solar disc.
The transit takes place on a weekday afternoon. Essentially all
places with public access will be open anyway with no need for special
permission. As long as the group with you is small, casual, and well-
behaved there'll be no trouble setting up in a public place to view
the transit.
If you intend to invite many people, like friends, to a private
property, please obtain beforehand proper permission from the property
manager. This will prevent nasty interventions by the manager during
the viewing. Usually all that's necessary is a due & proper notice to
the manager that so-many visitors are expected on such-&-such day and
time for a few hours, like for an afternoon social.
The one sticky factor could be your proximity to a sensitive
facility that doesn't like spying. Your astronomy gear could be taken
as part of suspicious action against the facility, like a monitoring
or targeting apparatus, You may have to show to the police what's
what. Have with you Venus transit litterature for the police.
Public viewing sessions
---------------------
In late May 2012 astronomy groups thruout the zone of visibility
of the transit are planning public viewing sessions. These are typicly
gatherings in open fields or yards where local astronomers have
properly protected telescopes to let visitors see Venus on the Sun.
Please know that only such sessions are we are advised of can be
enrolled here. A session away from our attention will be missed.
Like for any celestial viewing the transit is observable only in
clear sky, with some tolerance for thin cloud and haze. Clouds thick
enough to erase shadows, rain, strong wind, service disruptions, among
other causes, can call off a scheduled session.
Follow the advice of the sponsor. This is given when inquiring
about the session or in litterature sent to you, like by email. In
general, dress for the prevailing weather plus reasonably anticipated
Adverse weather,
==========================================
Sessions start at 17:00 unless stated otherwise. Info is correct
as at 2012 May 29. Viewing is cancelled for clouds unless stated
otherwise. The viewing site is NOT always the same as the club's
normal meeting site. OBTAIN LATEST NEWS DIRECTA MENTE FROM THE
CONTACT BEFORE HEADING OFF TO THE EVENT!! Skipping this crucial
step could cause devastating ruination of our Venus transit
experience.
===========
CONNECTICUT
-----------
Danbury CT. Westn CT St Univ, Midtown Campus, Sci Bldg roof. Free.
www.wcsu.edu/starwatch
-----
Greenwich CT. Curtis Elem Schl, Bowman Obsy. Astro Soc of
Greenwich. Free. rickbria@optonline.net, www.seocom.cgfom/asg,
-----
Stamford CT. Stamford Musm, Plm. $3 adm. Indoor show, telecast of
transit, talk. Clearsky outdoor viewing. cescovil@earthlink.net
www.stamfordmuseum.org
-----
Westport CT. Rolnick Obsy. Westprot Astro Soc. Free.
www.was-ct.org
=====
LONG ISLAND
-----------
Jones Bh LI. Roosevelt Natr Ctr. Amat Obsrs Soc. 17:30 in-house
observing, 18:30 public viewing. $4 adm, adv regn reqd. For
clouds, relocate to Sunken Meadow St Pk, else cancelled.
Stargazing after sunset requires previously obtained permit.
suerose@optonline.net, www.aosny.org
=====
MANHATTAN
---------
Amer Musm Natl Hist, Rose Ctr, 81 St entrance. $12 musm adm.
Indoor show, telecast of transit, no outdoor viewing.
www.amnh.org
-----
Intrepid Musm, Pier 86. Intrepid Musm & NYSkies Astro Inc. $5 adm
to pier, ship is closed for Enterprise prepaaration. Rain shelters
on pier. Personal starviewing after sunset on adjacent pier 84.
www.intrepidmuseum.org, algenib56@yahoo.com, nyskies@nyskies.org
-----
Riverside South Park, 70 St entrance. Amat Astro Assn. Free.
Supper break after sunset, then return for starviewing.
president@aaa.org, www.aaa.org.
-----
The High Line, 14 St entrance. Amat Astro Assn. Free. Supper break
after sunset, then return for starviewing. president@aaa.org,
www.aaa.org.
=====
NEW JERSEY
----------
Beachwood NJ, Jakes Br Cnty Pk. Astro Soc of Toms River Area.
Free. www.astra-nj.org, webmaster@astra-nj.org
-----
Booton NJ, NJ Rte 80, Exit 19, eastbd overlook. Sheep Hill
Astro Assn. Free. www.sheephillastro.org, wwestura@optonline.net,
contacts@sheephillastro.org
-----
Morristown NJ, Morris Musm. Morris Musm Astro Soc. Free.
ckkrish@gmail.com, info@morrismuseum.org, www.morrismusem.org
-----
Lebanon NJ, Teetertown Ravine. NJ AStro Assn. Free. www.njaa.org
-----
Livingston NJ, Riker Hill Art Pk. Newark Musm & No Jersey Astro
Gp. Free. planetarium@newarkmuseum.org, www.newarkmuseum.org
-----
Princeton NJ, Princeton Univ, Peyton Hall, Amat Astro Assn of
Princeton. 16:00. Free. Indoor show, then outdoor viewing at
Engineering Quad parking deck. Return to Payton Hall for telecast
of rest of trasnit. For clouds, entire show is at Peyton Hall.
info@princetonastronomy.org, www.princetonastronomy.org
-----
Sandy Hook NJ, western tip of peninsula. Amat Astro Inc. Free.
www.asterism.org, hfjacinto6@gmail.com
=====
QUEENS
------
York College, 160 St & Archer/Liberty Av. Free. View by projection.
www.york.cuny.edu/centers-institutes/observatory,
tpaglione@york.cuny.edu,
=====
STATEN ISLAND
-------------
College of SI, Astrop Obsy. Free. Whitelight & H-alpha viewing.
profirobbins@aol.com, robbins@mail.csi.cuny.edu,
supernova7.apsc.csi.cuny.edu
=====
UPSTATE
-------
New Paltz NY, SUNY New Paltz, Lecture Ctr. Mid-Hudson Astro Assn &
SUNY New Paltz. Free. Indoor talk, then outdoor viewing at
Coykendall Sci Ctr. For clouds, telecast of transit.
www.midhudsonastro.org, president@midhudsonastro.org,
maureendford@gmail.com
-----
Sleepy Hollow NY, Phelps Meml Hosptl Ctr, James House. Westchester
Anat Astro. Free. www.westchesterastronomers.org,
waa-president@westchesterastronomers.org
=====
Travel for viewing
----------------
It is not necessary to leave new York to see the transit, unlike
for a total solar eclipse. Unless you have convenience to be else
where, the view from the City is really a good one.
The farther west in the United States you are located, the longer
the view and greater the extent is because the transit begins earlier
on the clock in the local timezone. Sunset is more or less the same,
depending on latitude, at 20:20 in local daylight time.
Your astronomy gear could be inspected at airports, with potential
for confiscation! Have with you at ready litterature about the transit
to show the security agents. Offer to have certain items packed for
checked baggage if there's concern about having it with you in the
cabin, Be prepared to repack your baggage by modularizing your gear.
Stages of the transit
-------------------
The progress of venus across the Sun is marked by several stages,
or contacts. The transit begins when the disc of Venus first touches
that of Sun, they being tangential on their external edges. This is
first contact or contact I.
For whitelight solar observing, typical for viewing with front-end
solar filters or projection, this contact is not actually seen.
Instantly you see the tiny notch of Sun eaten out by Venus, first
contact is already passed.
When the discs are tangent on their internal edges, venus is just
completely onto the Sun. This is second contact or contact II. venus
marches across the Sun to the far side and hits contact II and IV to
leave the Sun's disc. For New York the Sun sets long before these
contacts.
The middle of the transit is when Venus is halfway along her track
across the Sun or when she is closest to the center of the solar disc,
with minimum separation from it. This stage is not obvious, but can be
deduced by measuring from photographs. It is not all that important
because it's the contact times that fix the end points of the track
across the Sun.
The transit begins in New York at 18:03 EDST. Venus procedes into
the Sun's disc and is about 1/3 way along her path when the Sun sets.
We do not get the midpoint of the transit yet still are treated to a
2-1/2 hour show. This is the order of a lunar or partial solar
eclipse.
Local circumstances
-----------------
Since the City was founded we experienced seven Venus transits as
at 2011 with three more in the next hundred and so years. The extent
of the transit visible from the City cover all possibilities.
------------------------------
extent | years
----------------------+-------
none visible | 1631 1761 1874 2117
in progress at sunrise | 2004
in progress at sunset | 1639 1769 2012
fully visible | 1882 2025
-----------------------------------
The table below gives specs for all ten transits. The first row
gives the date, the UT hour for each contact, minimum separation of
Sun and Venus in arcseconds, and Sun's right ascension and
declination.
The date, like for the 2012 event, is that prevailing at the
midpoint of the transit. See that the first and second contacts occur
before midnight; third and fourth, after midnight.
The second row gives the Greenwich Sidereal TIme at 0h UT for the
date, altitude of the Sun for each contact, and notes about the extent
of transit visible from the City.
------------------------------------------------------------------
Local Circumstances for Transits of Venus: 1631-2125 from New York
City. Geographic position: Latitude: N40.717, Longitude: W74.017
---------------------------------------------------------------------
Date I II mid III IV Sep" SunRA SunDE
G s T alt alt alt alt alt Remarks
interval between pairs
----------- ----- ----- ----- ----- ----- ----- ------ ------
1631 Dec 07 03:52 04:59 05:19 05:40 06:47 939.3 16.912 -22.64
5.045h -68d -72d -71d -69d -59d none visible
1639 Dec 04 14:57 15:15 18:26 21:36 21:55 523.6 16.738 -22.34
4.888h 22d 23d 23d -2d -5d I, II, mid visible
121-1/2 years
- - - - - -
1761 Jun 06 02:02 02:20 05:19 08:18 08:37 570.4 4.957 22.69
16.988h -15d -17d -26d -11d -8d none visible
1769 Jun 03 19:15 19:34 22:25 01:16 01:35 609.3 4.805 22.44
16.842h 55d 52d 20d -9d -12d I, II, mid visible
105-1/2 years
- - - - -
1874 Dec 09 01:49 02:19 04:07 05:56 06:26 829.9 17.056 -22.82
5.182h -48d -54d -70d -67d -63d none visible
1882 Dec 06 13:57 14:17 17:06 19:55 20:15 637.3 16.881 -22.56
5.025h 15d 18d 27d 13d 10d all visible
121-1/2 years
- - - - -
2004 Jun 08 05:13 05:33 08:20 11:07 11:26 626.9 5.121 22.89
17.137h -26d -26d -11d 17d 20d III, IV visible
2012 Jun 06 22:03* 22:21* 01:30 04:32 04:49 554.4 4.969 22.68
16.991h 24d 21d -11d -26d -27d I, II visible
105-1/2 years
- - - - -
2117 Dec 11 23:58 00:21 02:48 05:15 05:38 723.6 17.201 -22.97
5.320h -27d -32d -59d -71d -69d none visible
2125 Dec 08 13:15 13:38 16:01 18:24 18:48 736.4 17.026 -22.74
5.163h 10d 13d 26d 23d 21d all visible
---------------------------------------------------------------------
* Topographic times. All others in this table are geocentric.
------------------------------------------------------------
I grouped the transits in their 8-year pairs. The pairs are spaced
over a 100 years apart. I note the approximate interval between the
pairs in the third row.
This means that any living person may witness at most two
transits, those of the pair occurring in his lifetime. Not every one
will be so lucky. With current, extended, lifespans, you could live
entirely between transit pairs and never witness the show.
The transit times in this table are geocentric EXCEPT for the two
starred times in the 2012 event. These are the topocentric times for
the geographic location of New York, are closer to the observed time.
For the others, geocentric, ones the observed times may differ by
up to 10 minutes. Further more, the Sun's actual altitude may differ
by up to 2 degrees from this table due to the geocentric approximation
and atmospheric refraction.
Nearby towns
----------
I give here the specs for a few nearby towns to allow some
interpolation for sites a little ways beyond New York. Like for solar
and lunar eclipses and lunar occultations, you are ready a few minutes
ahead of time.
-------------------------------------------
Location | 1st contact | 2nd contact
---------------- | ----------- | -----------
name | EDST alt | EDST alt
---- | -------- --- | -------- ---
Albany, NY | 18:03:45 24 | 18:21:24 21
Hartford, CT | 18:03:43 23 | 18:21:22 20
New York, NY | 18:03:47 24 | 18:21:26 21
Philadelphia, PA | 18:03:50 25 | 18:21:30 21
---------------------------------------------
Path in the sky
-------------
For New York and generally thruout the NYSkies turf the transit
begins, first contact, when the Sun is in altitude 24 deg, azimuth 280
deg. He travels in sensibly a straight line diagonal to the lower
right to set in azimuth 301 deg. Azimuths are geographic, not
Manhattan grid.
A viewing site suitable for the Stonehenge sunset may be good for
the transit if it offers also a sightline over this path of the Sun.
One restricted to the gorge between towers along a street will not
such a suitable site.
The table here gives the altitude and azimuth of the Sun for New
York City to help select an observing site. It is substantially the
same thruout the NYSkies region.
-----------------------------------------
EDST | event | Sun al-az | remarks
------+-------------+-----+------+--------
18:03 | 1st contact | 24d, 280d | Venus hits Sun, 12:30 on limb
18:21 | 2nd contact | 20d, 285d | Venus fully on Sun disc
20:25 | sunset | 0d, 301d | Venus 1/3 across Sun disc
20:57 | civil twilt | -- | end of daylight activity
21:40 | nautl twilt | -- | full night in New York
--------------------------------------------------------
The moment of sunset wanders a couple minutes among references due
to the method of calculation and the allowance for air refraction.
Venus on the Sun
--------------
The transit is like an eclipse where the covering body is way too
small to fully hide the Sun. Venus when in front of the Sun is quite 1
arcminute diameter against the Sun's average 31 arcminutes. The dot of
Venus is tiny, just barely within discernibility by good eyesight with
suitable protection. Some people will spot this dot. Others miss it.
Any binoculars or spotting scope will clearly distinguish Venus
from a sunspot and allow you to follow her progress across the Sun.
Venus is a black perfectly round dot that obviously moves over the Sun
within several minutes. Sunspots are irregular shaded patches that
stay put on the solar disc during the transit. .
Venus enters the Sun quite at his upper limb, near the 12 o'clock
point around his disc. Venus travels diagonally to the lower right
toward the 4 o'clock point. She doesn't reaches even halfway there
before the Sun sets.
Sun-Venus size
------------
Seeing Venus, and also Mercury, marching across the SUn vividly
compares the linear size of a planet against the globe of the Sun.
Most pictures in astronomy boos and articles, even those meant for
instructing in the science, make the planets grossly too big, large
fractions of the Sun's size. In fact, from a remote viewpoint, it
would be real tough to tell that there is anything circling the
Sun.When detected, the planets seem like mere specks.
The largest of the planets, Jupiter, is just about 1/10 the
diameter of the Sun (but barely 1/a000 his mass!) and Earth is about
1/100 that diameter. Venus, being a little smaller than Earth, is
also about 1/100 the solar diameter.
As a side-by-side comparison during the transit, Venus is actually
TOO BIG against the Sun! Venus is about 1/3 as far from us as the
Sun
and appears about 3 times larger than if she was adjacent to the Sun.
Even with the too-large venus, you see just how humongous the Sun is
against a planet.
Venus atmosphere
-------------
While viewing the Sun at the ingress of Venus you MAY witness an
incredible feature. Sunlight COULD be spread around the edge of the
venus disc thru her own atmosphere, making a subtile outline off the
edge of the Sun.
This was seen by some -- but not all! -- observers at the 2004
transit from new York. At that time venus was leaving the Sun, having
been already in march on the Sun at sunrise.
An other effect happens just when venus is fully on the Sun, at
second contact. She pulls with her a thread of black 'mucus' like
thick ink, that finally snaps loose to leave clear Sun all around
Venus. This is the 'black drop' effect, also witnessed by some -- but
not all! -- observers in 2004 from the City.
Altho the cause is still unsettled the black drop ws captured from
spaceprobes examining transits of Mercury in recent years. Such views
rule out a terrestrial origin in the air. There could still be some
instrumental cause in the way sensing devices, including the human
eye, records the contact between Venus and Sun.
These two effects are seen, assuming the usual viewing methods,
only thru a filtered telescope that makes a comfortably large Venus
image. They are not discernible in low power or binoculars.
Weather
-----
The transit of Venus on 2012 June 5 is only a few days after the
first of New York's two Stonehenge periods. The situation for viewing
both events is about the same.
The Venus transit takes place in the New York summer hot & humid
season. You could be waiting for the sunset under oppressing
uncomfortable conditions. In such combination of temperature and
humidity, the body can not transpire properly, leading to sweatiness,
drowsiness, internal loss of water.
Wear light loose clothes, have a bottle of fresh water. Walk and
climb stairs slowly, don't run or jog. If feasible, view at a site
with nearby shade like trees or walls. Bring a folding stool or chair
to rest on. A battery -- or solar! -- powered fan can be very
refreshing.
One horrible threat against comfortable transit viewing is the
late afternoon thunderstorm. You could be trapped in one because
you'll be under the open air for several hours watching Venus creep
over the Sun.
In New York commonly on the summer days a tumultuous storm erupts
in the mid to late afternoon, throwing many centimeters of rain with
blinding lightning and crashing thunder.
The typical storm lasts only a half hour, but hour-long deluges
are annoyingly frequent. On the whole, regardless of the start and
duration, the storm abates before sunset.
This behavior of a common summer storm can knock out much of the
viewing period for the transit. There's nothing to do but take to
shelter and wait it out. It is prudent to have totable equipment which
can be scooped up and carried to safety, Else have at ready tarps to
cover heavier bulky gear.
You could be soaked thru and thru, taking on a nasty disheveled
feeling. The ground and street furniture may still be wet. Grassy
sites may still be soft and squishy under the foot.
In the event of the afternoon thunderstorm, arm yourself with
newspaper to lay on wet furniture, be willing to take splashes and
drips.
Rainbows?
-------
While the Sun is setting in the northwest, the antisolar point is
rising in the southeast. If there was a rain moving eastward after it
stops over you, there is the chance to spot a rainbow.
On the whole, storms sweep over the City from west to east, When
the sky is clearing in the west near sunset, rain could still be
falling in the opposite direction. This makes a wall of raindrops
catching the rays of the setting Sun to generate rainbows.
There's plenty of slack time to turn around and look away from the
Sun and look for a rainbow. The shadow of your head is the center of
the rainbow.
Because of a rainbow's large diameter, about 45 degrees, you
should ideally be at a site with an open view to the east and
southeast. With a street hemmed in by towers, you may see only the
upper segment of the bow centered over the street.
Nothing is promised, even if there was a rain that by sunset is
retreating into the east. The rain may have ended, moved out of
alignment with the Sun, or shrunk too small to make rainbows.
You could get a double or multiple bow! The extra ones are outside
of, and concentric with, the main bow.
Photographing a rainbow is a bit tricky. Metering off of the sky
itself can produce an overexposed picture. The rainbow is diluted with
weak color. Meter off of the foreground scenery, lock the setting, and
shoot with it at the bows.
Clouds
----
The transit is more like a lunar eclipse, a leisurely show lasting
many hours. A passing cloud only momentarily interrupts your viewing.
You may still observe the transit thru the thinner parts of clouds but
the thicker parts may dim the Sun too deeply.
Haze and certain clouds may diffuse the image, turning Venus into
a soft fuzzball. You'll recognize her by the perfectly round shape
and steady motion across the Sun. On the other hand a diffuse Venus
will weaken the effect of her ingress onto the Sun.
Never remove your solar filter to watch with only a cloud to
attenuate the solar rays! This is a most dangerous tactic! Leave the
filter in place and wait for the cloud to thin out or move away.
Bare-eye view
-----------
For the transit there is no cause to inspect the Sun by bare eye,
even tho he may be tempered by cloud. It is unlikely that you can see
Venus against the solar disc, even tho in theory it is just within
bare-eye resolution.
Thru safe filters, like the front end filter of your telescope
held before the eyes, you MAY can spot the black pinprick of Venus.
This is still a feat of keen eyesight. If you show the transit to
others,
For this reason I feel it is hazardous to hand out the solar
glasses, like those for solar eclipses. In an eclipse there is gross
change in the appearance of the Sun that is readily seen thru these
glasses. In the transit, Venus is at the threshold of resolution for
good vision and people may miss seeing her.
The possibility arises that people may fiddle with the solar
glasses in hazardous ways or try to see Venus without them. Children
away from supervision may horse around with the glasses. Disastrous
consequences can result from such unstructured use of the glasses.
filtered view
-----------
ALL optics used for direct viewing the transit MUST have solar
filtration devices fitted to them. Those used for projecting the Sun
onto a screen MUST be guarded or shielded against looking directly
thru them. Regardless of your personal experience with filtered solar
viewing, please mind well that other people observe your actions,
which speak orders louder than your words. Stay well within bounds of
safe operation for solar viewing apparatus.
Have a properly-made solar filter for the front end of your
optics. There is no safe filter for the back end at the eyepiece. If
your scope has a filter fitting over the eyepiece, please discard it
before it falls into ignorant hands.
Do not try to make your own filter with assorted dense materials.
There are articles out there that piously claim that a such-&-such
snack bag plastic is safe but there is no simple and sure way to tell
if the sample in hand is that certain kind.
By April and definitely by May 2012 there could be few solar
filters left in stock at astronomy dealers. In addition to the transit
there is an annular eclipse in May in western United States and a
total eclipse in the South Pacific in November. These caused extra
demand for solar filters.
I hope you still have suitable filters from previous eclipses or
the 2004 transit.
Projected view
------------
Projection onto a screen from your optics is a safe way to show
the transit to many people at once. Guard the instrument by barriers
or shields against looking into its eyepiece. Venus is easily spotted
in the projected image and she can be marked on the screen to show her
progress across the Sun.
A sun-cone or sun-funnel can be made from cardboard and tracing
paper. The narrow end is strapped around the eyepiece. The wide end
is covered with smoothed and taped tracing paper. The Sun is focused
thru the eyepiece onto the paper to form an enlarged image. It is
viewed on the paper from the wide, upper, end of the cone/funnel.
Projection usually lets the full strength of sunlight into the
telescope, strongly heating the eyepiece area. The scope should be
capped or covered between views.
Pinhole projection, common for solar eclipses, will not show
Venus. She is too small and will be diffused out of sight.
Imaging devices, cameras, are a possibility. attached to the
eyepiece end of the scope and displayed on a computer or television
screen this method can accommodate a large number of viewers.
Make SURE your apparatus is rated for direct input of solar rays!
Even with a front-end filter some imaging units could be burned to
death by sunlight entering them. Consult with the device manufacturer.
In case of clouds you can arrange viewing by Internet taken from
an other location in the clear. Test the availability and reliability
of Internet signal at your viewing site before the transit.
Helioscopic views
---------------
I use this term to mean specialty devices to observe the Sun in
other than plain whole-spectrum white light. Typical examples are
hydrogen-alpha and coronascopes. These will show amazing structure on
the Sun that changes within minutes but suffer from severely dim image
under outdoor daylight.
You may have seen the SUn thru one of these devices at starparties
or conventions and had to hood yourself to keep daylight out of your
eyes. The sight of a inky black Venus spot sitting on top of a solar
flare can be incredible!
An other possibility is that the helioscope may show prominences
or flares right at the ingress point. Venus could then be silhouetted
against that feature before she enters the solar disc! This could be a
way to alert others in your party, observing in white light, to be
ready for the first contact.
Photography
---------
Photographing the transit is the same as taking pictures of the
Sun for an eclipse. You may attach the camera to the eyepiece end of
the telescope with the dame couplings and fittings and use the same
settings for exposure. For digital images, you have the chance to edit
the pictures to remove defects like light leaks and flare.
Hold the camera up to but not touching the eyepiece. Aim straight
into the eyepiece, keeping the camera optical axis (centerline of the
lens) in line with the exit beam of the scope. The viewing screen of
the camera is a far better means of framing than the viewfinder of a
chemocamera. You may have to block stray light from intruding into the
camera with a dark cloth loosely wrapped around the camera and
eyepiece. Hold your breath, stand still, gently press the shutter
button. Let the camera do its thing.
The major defect you'll suffer is focusing. If you can force the
focus to infinity, do so. Else hope the camera relaxes to some far
setting when confronted with a strange scene like the inside of a
telescope.
You can photograph the projection screen as an ordinary landscape
scene with no special adjustment of the exposure. Keep direct sunlight
out of the camera by shading its lens with your hand. This same method
works for photographing a computer or television screen.
Be sure to take pictures of the people and scene at the viewing
site! These pictures give extra significance to the transit images.
Simulation
--------
To cover interruptions by clouds you can run a simulation of the
transit with a computer planetarium program. Use the 'realtime'
feature to run the animation in pace with the sky. You have to do a
time set to get the computer clock in synch with true local time.
Lacking a computer you could build a mechanical model from a thin
steel white=painted sheet and a round magnet. Move the magnet over a
drawn solar disc in step with the progress of the transit.
Conclusion
--------
This is the second of the current pair of transits, the previous
one being in 2004. After this one there are NO MORE chances for the
next 105 years! Neither you nor anyone living today nor anyone born in
the next decade or so will ever see the next pair of transits. They
come in 2117 and 2125.
The killer is weather. This slaughtered many expeditions in the
1760s and 1800s, treks litterally lasting months from Europe only to
end with astronomers huddled in a tent pelted by heavy rain.
In spite of advances in science and industry we still can not
confidently foretell weather even a few days in advance! Yet, and I
kid you not, when I asked around for a global visibility diagram of
the 2012 transit, there were none of modern design. I had to avail of
charts from my transit of Venus textbook that was in wide use thru the
whole of the 20th century. It was written to prepare for the previous
pair transits in -- hold your hat -- 1874! Yes, it is spot on for
delineating just where the next transits, in the appallingly far off
21st century will be visible