Looking for Eclipse Glasses? Protect your eyes while viewing the transit. Purchase IceInSpace Eclipse Glasses from the IceInSpace Shop for $4 each, or $3.50 each if you buy 4 or more.

The Transit of Venus across the face of the Sun occurs on June 5th or June 6th, 2012 depending on your location. This is an extremely rare event, and will be the last time you'll have a chance to see this in your lifetimes!

Observers in Eastern Australia and Eastern Europe will see the entire transit, starting from shortly after sunrise on the 6th June. If you live in Western Australia, Western Europe or East Africa, the transit will be in progress at sunrise on the 6th June. Observers in North America will see part of the transit on the 5th June, but the sun will set while it is in progress.

The diagram below shows the locations where the transit is visible. Read on for more information including what is a transit of venus, local timings for your location, hints and tips for safe viewing and photographing the eclipse.

Have questions? We'd love you to register at the IceInSpace Forums and don't be afraid to ask in this discussion thread. To see images and read reports after the event (and to post yours too!), check regularly in the Observational Astronomy and Solar System sections.

Click to Enlarge World Map showing visibility of the June 2012 Venus Transit

Use the links below to find the information you're after:

• What is the Transit of Venus?
• Historical Significance for Australians
• When and where can I see it?
• Safe Viewing Guide
  • Observing the transit safely
  • Purchasing Eclipse Glasses
  • Online webcasts
  • How big will Venus appear?
• Photography Guide
  • Pre-Planning
  • Equipment
  • Environmental
  • Setup
  • Capture
• Example Images
• Transit Tours
• Upcoming Venus Transits
• References, Further Reading and Resources

What is the Transit of Venus?

A Transit of Venus across the Sun occurs when the orbit of Venus takes it directly between the Earth and the Sun, obscuring a small portion of the Sun's disc. During the transit, Venus appears as a small black disc moving across the sun, usually taking several hours.

Transits of Venus across the Sun are extremely rare - one of the rarest of the predictable astronomical events, occuring in a repeating cycle of 243 years, with a pair of transits 8 years apart every 121.5 years and 105.5 years.

The last transit in the current cycle was in June 2004, but before that the last transit was in December 1874 and December 1882. The next transit after this one will be in December 2117 and December 2125 - so this is the last chance to see a transit of Venus in our lifetimes!

The image below is from the 2004 transit and shows what to expect. There are many more example images further below.

Click to Enlarge A collage of Venus Transit images from 2004. Image credit: Ken Peterson

	Click to Enlarge Drawings of the 1769 transit of Venus by James Cook

Historical Significance for Australians!

The transit pair of 1761 and 1769 were used to try to determine the precise value of the astronomical unit (AU) using parallax - ie: to try and measure the size of our solar system. Following the proposition put forward by Edmond Halley (who had died almost twenty years earlier), numerous expeditions were made to various parts of the world in order to observe these transits; an early example of international scientific collaboration.

Observing and timing the 1769 transit was the main reason that Captain Cook and Charles Green were appointed by the Royal Society to travel to Tahiti in 1769 (see sketch right). After the transit on the return voyage, Cook searched the South Seas for months looking for the great southern continental land mass, Terra Australis, that it was thought was necessary to balance the great continental masses in the northern hemisphere. There was no such continent but in the process, he stumbled upon Australia.

Read more about Cook's voyage on the NASA page, James Cook and the Transit of Venus.

When and Where Can I See it?

The entire transit will be seen from north-west Canada, Alaska, eastern and northern Asia, the eastern half of Australia, New Zealand and the islands of the Western Pacific Ocean.

The Sun will set while the transit is in progress in the area encompassing eastern Canada, the United States, central America and the north-western part of South America. The Sun will rise while the transit is in progress in the area taking in south-west Asia, eastern Russia, the Middle East, north-eastern parts of Africa and most of Europe.

For Australians on the East coast (including Sydney, Brisbane, Melbourne, Tasmania etc):

• The transit will begin on June 6th 2012 at approximately 8:15am AEST while the Sun is fairly low in the sky (approx 13-18deg altitude depending on your latitude).
• The mid-point of the transit occurs at around 11:30am while the Sun is at approx 35-40deg altitude.
• The final contact points of the transit occur at approx 2:30pm with the Sun at approx 20-25deg altitude.

For West Australians (Perth),

• The transit will be in progress at Sunrise on the 6th June, so you'll miss the first contact points, but you'll still see 4-5 of the transit.
• The mid-point of the transit occurs at approx 9:30am (local time) with the sun at 22deg altitude.
• The final contact points of the transit occur at approx 12:30pm with the sun at 34deg altitude.

For other cities around Australia or around the world, use the table below to find the city closest to you.  If your location is not listed, try this interactive web form. Simply enter your nearest city in the search box and click 'Find Coordinates', or enter your latitude and longitude and timezone and click 'Compute'.

Some defitions of the contact points:

• First contact: the smaller body is entirely outside the larger body, moving inward ("exterior ingress")
• Second contact: the smaller body is entirely inside the larger body, moving further inward ("interior ingress")
• Third contact: the smaller body is entirely inside the larger body, moving outward ("interior egress")
• Fourth contact: the smaller body is entirely outside the larger body, moving outward ("exterior egress")
• Maximum Transit is mid-way through the whole transit.

If you're in a location where the transit is not visible, or you're clouded out, or you don't have the required safety glasses or filters, watch it as a live webcast from the comfort of your home using any of these online resources.

The table below shows the timings for the points of contact during the Solar Eclipse. The times are given in local time for that city. 

* Transit times generated from www.transitofvenus.nl

The animation below will show you how the transit will appear and at what times of day from your location. It tries to automatically detect your location, so if it's incorrect, simply click the map to enter your latitude/longitude.

Click Play to begin the animation again.

Animation powered by SunAeon.

Safe Viewing Guide

WARNING! Never look directly at the Sun with the unaided or unfiltered eye, or permanent eye damage can result. You must take precautions - use properly filtered "eclipse glasses", or use special techniques to view the Venus Transit. Never view the Sun through a telescope or binoculars unless it is fitted with a specially designed Solar Filter. Read below for a number of techniques to view the transit of Venus.

Pinhole Projection Method

This is the easiest way to view the transit, and does not require any special equipment apart from one or two thin, stiff pieces of cardboard (white is best). Use a pin to poke a small, crisp hole in a piece of cardboard - this allows an inverted image of the Sun to be projected onto the second piece of cardboard below. Do not look through the pinhole at the Sun! Make sure the pinhole is as small and crisp as possible - the larger the hole, the fuzzier the image will be. Use this method with your back to the Sun, and the cardboard should be perpendicular (at 90° angle) to the direction of sunlight to give the least distorted image.

While the resources below mention solar eclipses, the same technique can be used for the transit. Because the image is not magnified, it may be difficult to spot Venus as a small black dot but it should definitely be possible.

Some resources for building Pinhole Projectors:

• How to make a Pinhole Projector.
• The Pinhole Projector
• Indirect Eclipse Viewing Methods (pdf)

Click to Enlarge Pinhole Projection - courtesy eclipse-chasers.com

Eclipse Glasses

Special "Eclipse Shades" or "Eclipse Glasses" are available to purchase from the IceInSpace Shop, which use a specially filtered film which you can directly view the Sun safely. The "frames" are made from light carboard and it's best to hold onto them securely while observing the Sun.

The filters in the glasses are optical density 5 or greater and are “CE” certified which meets the transmission requirements of scale 12-16 of EN 169/1992 (Australian standard AS 1338.2 and 1338.3).

The lenses are made of exclusive scratch resistant optical density 5, “Black Polymer” material. Eclipse Shades filter out 100% of harmful ultra-violet, 100% of harmful infrared, and 99.999% of intense visible light. These premium filters create a sharper ORANGE coloured image of the sun. The backside is printed with information for safe use and warnings about correct usage.

Again this provides an unmagnified view of the Sun, so Venus may be difficult to spot, but it is definitely possible to see the transit with an unmagnified view.

Buy in bulk for family and friends, teachers and work mates, classrooms and hobby groups, and look cool in IceInSpace branded Eclipse Glasses for safe viewing of the Sun.

You can purchase IceInSpace Eclipse Glasses from the IceInSpace Shop for $4 each, or 4 for $14.

Click to Enlarge IceInSpace Eclipse Glasses		Click to Enlarge IceInSpace Eclipse Glasses

Solar Filters and Binocular and Telescope Observing

The only safe way to view the Sun through Binoculars or a Telescope, is to fit a proper solar filter to the Sun-facing end of the optics. Never use "eyepiece" solar filters that screw into the eyepiece-end of a telescope. These are not safe and can crack under the intensified heat from the Sun.

Solar Filters are usually white-light filters, cutting out harmful wavelengths and allowing only safe white-light through the filter. These will allow you to view the Sun through your binoculars or telescope. The Sun will appear as a white (or yellow, depending on the filter) disc, and you will see Venus as a black dot covering part of the Sun. You will also see any sunspots that are visible at the time.

You can also get special Hydrogen-Alpha Solar telescopes or filters, which allow you to view the Sun in narrowband wavelengths so you can see surface details on the Sun such as flares and filaments, and prominences rising out from the limb. Again you will see Venus as a dark disc covering part of the Sun. Hydrogen-Alpha telescopes (such as the Coronado PST or SolarMax II 60mm Solar Telescope) and filters are much more expensive than white-light filters but the view is considerably better.

Some resources for where you can buy, and how to make safe Solar filters:

• Bintel Solar Observing Products
• MyAstroShop Solar Filters
• Making a White Light Solar Filter

Click to Enlarge Home-made white-light solar filter - credit: Mike Salway		Click to Enlarge Group-shot showing various solar filters and observing methods - courtesy Craig Michael Utter (S&T)

Build a Sun Funnel for Group Observing with a Telescope

I saw this nice idea on Transit of Venus.org, and looks like an effective way of viewing the transit using a refractor, when you don't have a filter to cover the end of the telesocpe. It will also be useful for group viewing, as observers don't need to look through an eyepiece, try to focus the telescope etc. Many people can view it at once.

While these instructions and parts are for the US, you will be able to find similar products at your local hardware store no matter where you live.

• How to Build a Sun Funnel

Click to Enlarge Sun Funnel. Image credit: Rick Feinberg		Click to Enlarge Sun Funnel on a telescope. Image credit: Rick Feinberg

Project a Magnified View

You can use this method with unfiltered binoculars or a telescope, and allows a magnified view of the Sun as it is projected onto a white piece of cardboard behind the eyepiece or binoculars.

You only need 2 pieces of cardboard to make this projector. The first fits over the objective end of the binoculars or telescope; cut out a hole to make it fit snuggly and use duct tape to hold it in place or cover any gaps. The second piece of cardboard is held at a distance behind the eyepiece, and a projected view of the Sun is cast on the cardboard allowing you to observe the transit.

Remember to cover the second objective of the binoculars, and any finderscopes of the telescope.

Special care must be taken though - never leave this setup unattended as looking through the eyepiece at the unfiltered Sun will cause permanent eye damage! Also, the concentrated suns' rays will be very hot and can burn if left for a long period of time.

This setup is what I used during the 2004 transit (photos below), as I had nothing else ready at the time. I simply held a white sheet of paper or cardboard about 50cm-90cm behind the binoculars.

This article has a few more pictures and instructions for this method:

• Projection method for observing the transit

Click to Enlarge A piece of white cardboard is simply held at a distance behind the eyepiece		Click to Enlarge Holding the sheet of paper in one hand, and a camera in the other :) Venus has just moved into the disc at about the 5 o'clock position
Click to Enlarge Another example of the projection method using binoculars. Image credit: Ivan (lepton)		Click to Enlarge Projection method using binoculars. Image credit: Ivan (lepton)
Click to Enlarge An example of the projection method using a telescope. Image credit: Mick		Click to Enlarge Projection method using the refractor. Image credit: Mick

Online Webcasts

If you're not in a location where the transit is visible at all, or you're not in a position to get outside and use any of the methods above, then you can watch from the comfort of your computer chair as a live webcast using any of these online resources:

• Transit of Venus.com.au
• TBA - will be updated as they are announced.

How Big Will Venus Appear?

Venus is approximately 1 arcminute in diameter, while the sun is 32 arcminutes - so Venus will be a small black disc moving across the Sun.

With an unmagnified view (eclipse shades, pinhole projector), it will be difficult to spot Venus near the edge but will definitely be visible to most people. A magnified view (projection method, filtered telescope) will give a much clearer picture of Venus as it transits the Sun.

Have a look at the example image below from the 2004 transit, and other example images on this page to get an idea of the scale and what to expect.

Click to Enlarge 2004 transit. Image credit: Stephen Duffield

Final Warning!

Do not try to observe the transit with your naked eye, or with normal or cross-polarised sunglasses - these do not offer protection against blindness if you stare at the Sun. Never use "eyepiece" solar filters that screw into the eyepiece-end of a telescope. These are not safe and can crack under the intensified heat from the Sun.

IceInSpace offers this information as a guide only and does not take responsibility for anyone using unsafe observing practises.

By their very nature, transits across the Sun are viewed outside in the Sun. Ensure you have adequate skin protection including hat and sunscreen.

We'd love to hear about your transit observing experiences! Please register and post your observing reports in the Observational Astronomy section.

Photography / Imaging Guide

Photographing a Transit of Venus isn't extremely difficult, but does take some special planning and preparation if you want to do it well. 

It is vital that you have a clear idea of what you want to achieve, otherwise on the day, you will be in a flap, not knowing which camera to use on what ‘scope, and when in the sequence.

Pre-Planning

Visualise what you want to record, and how you want the finished work to look, and that will help dictate your telescope/camera combination(s). Here are some possible imaging scenarios.

1. Images of the full disc of the Sun with Venus appearing as a small, black dot in transit.
2. Close ups of Venus at the 4 critical points of 1st & 2nd contacts, (ingress) and 3rd & 4th contacts, (egress).
3. Close ups of Venus adjacent any sun spots, if we are lucky!
4. An animation of Venus as it passes across the face of the Sun.
5. A single, composite image showing the path of Venus across the face of the Sun.
6. If planning a mosaic and there are sun spots on the disc, then be aware that the sun spots will elongate and smear during the time duration of the mosaic.

Equipment

Which camera are you going to use? What telescope are you going to use?

• Webcam
• DSLR
• Dedicated astronomy camera
• Camera and lens

Decide on what image you want to achieve. Select the appropriate camera and ‘scope combination to produce that image, whether full solar disc for a composite and possible animation, or hi-res close ups. Practice with the set up at least once before the transit, even if it means taking images of a blank solar disc.

Field of view examples

Here are some typical sensor/scope combinations available to many, courtesy of the “Field Of View” indicator options in The Sky Professional, Version 6, from Software Bisque:

• Vixen 102mm f9 refractor with DSLR at prime focus, for images of the full disc of the Sun with Venus appearing as a small, black dot in transit.
• Vixen 102mm f9 refractor with ToUcam and x2.5 Powermate for close ups of Venus adjacent nearby sun spots, if we are lucky!
• Celestron C9.25 with F6.3 Reducer/Corrector and DSLR for images of the full disc of the Sun with Venus appearing as a small, black dot in transit.
  

Click to Enlarge Figure 2 - Field of View examples

Environmental

• It’s going to be a tough day at the office on 6th June, so be well prepared.
• Viewing a notebook display and trying to focus on a small black dot will be nigh impossible in full daylight, so shield the notebook computer from bright daylight. Try a portal observing hutch with a curtain, or a deep cardboard box.Make sure the open end of the box is facing away from the Sun.
• Have a hat and sunscreen ready for exposed parts for when the Sun gets higher. Keep sunscreen off optical surfaces and equipment! Wear comfortable, lightweight clothing to protect you from the Sun, without overheating.
• If you are going mobile to find a good eastern horizon, don’t forget the necessities like water, food, snacks, a chair, etc.
  

Setup

• A good polar alignment will contribute to good tracking with minimal manual intervention required – remember you will be quite busy at certain critical times, such as ingress and egress.
• Make sure you have all the necessary cables and adapters to fit camera(s) to telescopes.
• Focusing can be tricky unless there is a sunspot to pre-focus on.
• Work out the orientation and predicted path in advance, so your ‘scope is pointing to the correct segment of the solar limb. Or, if using GoTo, you can work this out by doing a GoTo on Venus; although remember that you won't be able to see it until it starts crossing the disc of the Sun.
  

Capture

Short Focal Length Telescope View

Ensure your telescope is fitted with a properly designed solar filter before attempting to observe or photograph the transit through a telescope! For this method, you want to see the whole solar disc. So choose a focal length where you can fit the whole Sun in the Field Of View (FOV) of your telescope and imaging device. Some examples of this could include:

• AFocal Imaging with a low-power/wide FOV eyepiece. Simply attach your camera to the eyepiece using a camera adapter, or hold the camera pointing into the eyepiece and click away.
• Prime Focus imaging using the Telescope as a long focal length lens. This is where the imaging device (DSLR or webcam) sits in the focuser in place of the eyepiece.

You can take images during various stages of the transit to present a final composite showing Venus as it moves across the disc of the Sun. Or you could simply use a single image with Venus at an interesting place on the disc - for example, near the limb or near a sunspot.

Some examples, courtesy Fred Espanek:

• Composite of all phases
• Single Totality image
• Image of Partial Eclipse

You could also take a sequence of images over the entire transit (for example, every 10 minutes), resize them down and present an animated gif showing a "movie" of Venus moving across the disc of the Sun.

Two examples showing an animated gif like this, are courtesy Fred Espanek - both from eclipses in 1994. Annular Solar Eclipse Animation. Total Solar Eclipse animation.

Long Focal Length Camera View

You will need to use a Solar filter fitted to the end of your lens.

You will need to choose as long a focal length as you can to make the sun more magnified on your camera chip. Anything under 300mm and it will be very difficult to pick out Venus - it will just be too small.

Using a normal digital camera sitting on a tripod or equatorial mount, choose your longest zoom setting or longest focal length lens (using a DSLR) and frame the Sun. Take test shots to check your composition and exposure. Make sure you use the histogram function on your camera to ensure that you're not clipping either end of the histogram (not overexposing or underexposing). Zoom in on the preview screen to check that your focus is sharp. Most cameras should be able to get an autofocus lock on a bright object like the Sun, so focus shouldn't be too much of an issue.

If your camera is able, once you've got a focus lock, change the focus to Manual so that it doesn't change between shots. For a normal compact digital camera (not a SLR/DSLR) change the focus to the "infinity" setting and leave it there.

The exposure won't need to change during the transit unless you get clouds moving in front of the Sun. Typical exposures will range between 1/250th second to 1/4 @ f8 ISO400. Exposures will need to be longer if you use a lower ISO.

Keep your ISO setting low (eg: ISO100) to minimise the noise. It's also worth bracketing your shots or simply check the image afterwards and re-shoot if necessary. During haze, fog or high cloud you will need to increase the exposure.

High Resolution Telescope Imaging

Ensure your telescope is fitted with a properly designed solar filter before attempting to observe or photograph the transit through a telescope!

This technique involves using a webcam or dedicated astronomy camera in conjunction with your telescope to get a more magnified view of the Sun. It may be the whole disc, or it may be just the part of the disc where Venus is transitting. It depends on your telescope and camera, and any barlow lenses you use.

The techniques used are similar to any high resolution imaging with your telescope and webcam, whether it's the Moon, a planet, or the transit of Venus. You will capture a "movie" or sequence of images using the cameras recording software. Each sequence needs to last no more than a minute or so (you don't want Venus to visibly move during the sequence).

Each individual movie/sequence will be processed using software like Registax to pick the sharp frames and stack them into a final image.

You can take sequences during various stages of the transit to present a final composite showing Venus as it moves across the disc of the Sun. Or you could simply use a single image with Venus at an interesting place on the disc - for example, near the limb or near a sunspot.

Planning, Preparation and Trial Runs!

Planning and preparation is the key to capturing successful, and somewhat stress-free transit photography.

• Plan the type of transit images you want to capture
• Ensure you know, and are aware of the timings of each stage of the transit
• Ensure you have accurate time (eg: GPS) available to you
• Ensure you have a solid, heavy tripod to ensure your camera doesn't vibrate or shake during exposures
• Use a camera remote or shutter release cable to avoid touching the camera
• Make sure you have all the obvious essentials - spare batteries, solar filters, tape, bags, umbrella, sunscreen and hat, etc.

The day of the transit is not the right time to be trying new equipment or new techniques. Make sure you practise! Go out on any sunny day and do a couple of trial runs - set up all of your equipment and practise focusing, composing, trialling different exposure settings, etc. Be well prepared and practised.

Example Images

To set the scene and whet your appetite, here are some images I hunted down through IceInSpace or elsewhere on the internet, showing what previous imagers have achieved.

The main difference between 2004 and now, is the affordability and availability of hydrogen-alpha telescopes like the PST, as well as webcams and DSLR's. So after this transit we're going to see plenty of jaw-dropping, stunning images of the Sun with prominences, filaments and sunspots, with Venus transiting. It's going to be great!

Click to Enlarge Great timing! Taken with a Nikon D70 through a telescope. Greg Bradley.		Click to Enlarge Image using a Celestron C8 with mylar filter, and a compact camera held to the eyepiece. Gary Kopff.
Click to Enlarge 4 great views of the transit taken with an Olympus OM1 film SLR on a 10 inch telescope. Ken Peterson.		Click to Enlarge Venus Transit. Jan Herold.
Click to Enlarge Image with a 4 inch F15 refractor with full aperture solar filter and 35mm canon SLR camera and 100 ASA film. Exposure 1/125s. Stephen Duffield.		Click to Enlarge Image with a 4 inch F15 refractor with full aperture solar filter and 35mm canon SLR camera and 100 ASA film and a barlow. Exposure 1/125s. Stephen Duffield.
Click to Enlarge Pronto with Canon 10D and 2X converter. Bruce Collier.		Click to Enlarge Image by NASA taken from Space (TRACE telescope).
Click to Enlarge TMB 100mm f/8 Apo Refractor SBIG STL 11000XM. Stefan Seip.		Click to Enlarge Coronado SM60, DSLR. Tonk.

Final Word

This is the last transit of Venus you'll see in your lifetime - so make sure you at least take the opportunity to observe it (safely) and enjoy the experience - don't get so hung up on photography that you forget to actually observe the transit. You have 4-6 hours so there's plenty of time to do both!

Have questions? We'd love you to register at the IceInSpace Forums and don't be afraid to ask in this discussion thread. However you choose to photograph the transit, we'd love to see your results posted in the Solar System section.

Transit Tours

While the Transit of Venus can be viewed from large parts of the world, there's still a lot of the world that won't get to see it, as the Sun will be below the horizon for them while it takes place.

Being such a rare event, there's going to be people who will want to travel to see it - whether it's to another country, or even to a better part of the country where observing conditions and chance of clear skies are better!

There's also the historical significance, and people will want to travel to take in the history of the event.

Here's a few suggestions of tours that you might consider.

• TravelQuest Tahiti Transit of Venus Tour
• Ring of Fire Expeditions Transit of Venus Expedition to Turkmenistan
• Melita Trips Transit of Venus Tour to Hawaii
• Sky and Telescope and Insight Cruises Venus Transit Tour to Hawaii
• Astro Expeditions Annular Solar Eclipse and Venus Transit Tour to North America and Hawaii
• Solar Eclipse Tours Transit of Venus Tour to Australia or Tahiti

Please note: These were simply gathered from a web search and posted here for your convenience. They are not an endorsement or recommendation. If you have any tour suggestions, please get in touch with me.

Upcoming Venus Transits

As mentioned earlier, transits of Venus across the Sun are extremely rare. The table below highlights this! The next transit isn't until 2117 and then again in 2125. If you miss those, you have to wait another 121.5 years! And in the table below, covering 250 years, only the first one is visible from Australia.

So make sure you do what you can to observe this June 2012 transit, and hope it's not cloudy!

References, Further Reading and Resources

• NASA Transit of Venus page
• Transit of Venus.org
• Transit of Venus.nl
• HMNAO 2012 Venus Transit page
• Transit of Venus.com.au
• Wikipedia Transit of Venus page
• Joe Cali Transit of Venus page
• Some photography information adapted from the Transit of Mercury article by Dennis Simmons.
• IceInSpace Discussion Thread