How to Watch
This is the most important question after ‘when is it happening?’. Looking directly at the Sun is sheer stupidity, so you’ll need some equipment.
The cheapest and least effort-requiring alternative
Solar goggles will be sold in your neighbouring areas somewhere. Get them. Make sure that these are proper by checking that you can look at the sun comfortably without your eyes hurting even a bit! Make-shift goggles made out of old X-Ray plates might not be a good idea, especially for the sun in the afternoon or late morning. Venus or no Venus, your eyes are the most important things to take care of. Never forget that!
Cheap alternative, but requires a bit more handiwork
One cheap way to look at the transit is to project it. You’ll need a few things and I think you’ll enjoy the thrill of making a simple tool to observe a cosmic event. You’ll need two magnifying lenses – one being the eye-piece and the other the objective. Make sure that the objective is a bigger lens than the eyepiece. Make a simple cardboard roll. Place another roll inside it, so that it fits snugly, but can still slide without too much of a problem. Place lenses properly within the rolls (before sticking them permanently, of course), so that you can get a decent image. Adjust the distance after that by sliding one cardboard roll against the other and ensure proper focus. Aim it at the sun and project it onto a white sheet of paper.
If properly focussed, you should be able to see Venus quite clearly! Strict warning: Do NOT look through the telescope while it is aimed at the sun. This is more dangerous that looking directly at the Sun, since the telescope actually collects sunlight and focuses them. You’ll run a serious risk of being blinded! Do NOT do it!
Not so cheap alternative
If you’re a member of the local amateur astronomy club, or if they are organising something in the locality, then, filters on a proper telescope is the best way to go! Make sure the guys use proper filters – red-orange filters are the way to go. The filters should be of good make, otherwise prolonged exposure might damage the filters and, in turn, the telescope CCD. With the filters installed, you can actually look directly at the Sun! The glory of Venus making its way should be evident! The upside of a fancy telescope is that you’ll also be able to see a few sunspots.
The filters aren’t too expensive, but they aren’t dirt cheap either! So if you’re the handyman and your friend has a telescope, collaborate to set up something that you can tell your grandchildren about.
Capturing on the Camera
Unfortunately the only way to get a good image of the transit on film (real or virtual) is to actually point the camera into the sun and click. With the Sun being so bright, this is a very bad idea; your camera CCD/film will not like it! The only way around that is filters. Make sure you have red-orange filters of appropriate shaped for your camera lens, before you even think of aiming at the Sun and clicking. Contact your local amateur astronomy club(s) or planetaria for the exact filters needed and available. Search for ND5 filters (Neutral Density-5 filters), if possible.
What to watch for
Venus entering and/or exiting the solar disc will be a treat. It will look like an oil drop falling into a liquid. Venus has a dense atmosphere, making the edges of the planet blur out against the bright disc of the Sun. Towards the end of the transit, a thin sliver of the sun’s disc will be visible between the edge of Venus and the edge of the solar disc. As Venus proceeds further, this sliver will also be “pinched off”. That’ll be a sight to behold.
The Venus Cycle!
Now, onto the real nitty gritty of the cycle of Venus. When can we see the transit and does it really have a period?
It turns out that it does – a massive period of 243 years! The transit of Venus will occur in a pair and then be separated by a relatively long time. The pair transits will differ by 8 years. The last transit occured in 2004 and this one is occuring this year – after 8 years, on the dot! But then this will be separated by a long 105.5 years, with the one after this year’s occuring in 2117 (December). The cycle is pretty complicated. The one after that will occur in 2125 – after the proper 8 year cycle (December again!). The one after that will occur after 121.5 years!
So the complicated cycle looks like this: 8-105.5-8-121.5 years between two successive transits. This entire 243 year cycle is then repeated. Look above for the diagrammatic representation.
So let’s look at the takeaway points:
1.Take a look at the GMT time and figure out the time for the transit in your area.
2.Make sure that you have proper equipment for observing the event. Do NOT see it with the naked eye. Projection onto a surface is an easy way. But it will require a little preparation. Youtube videos are your friends!
3.Look for solar goggles of good make. Remember, your eyes are of foremost importance, not Venus! The best solution – and the most expensive one – is buying filters for a telescope. This will give you a magnified and sharp image.
4.If you are geographically lucky enough to see the start or the end, do keep an eye out for the “pinch-effect”.
Have fun! Watch the Venus Transit safely.