TRANSITS of Venus, unlike those of Mercury, are visible to the naked eye. Since Venus is nearly one arcminute in diameter, it is visible without any optical aid as a small black dot passing over the disc of the sun. Never look directly at the sun. If you look at the sun with or without a telescope you will damage your eyesight.
The safest way to observe the transit is by projecting the sun through a small refracting telescope onto a piece of card. Never look along the telescope to line it up. Always have your back to the sun and use the shadow of the tube to home in on the sun. Keep finder scopes capped at both ends for safety. If you want to observe the transit directly, you must use a genuine solar filter. Make sure it has a proper mounting that securely fastens to the telescope. Even with a properly fitted frontal solar filter, make sure that you do not accidentally glance at the sun.
