Transit of Venus Story
A transit of Venus occurs when Venus passes directly between the sun and earth. This alignment is rare, coming in pairs that are eight years apart but separated by over a century. The most recent transits of Venus were a thrilling sight in June 2004 and 2012, with the next transit of Venus pair occurring in December 2117 and 2125.
Observers from two locations on earth see two distinct paths (red and blue) of Venus across the sun. The slight difference in times Venus takes, moving from edge to edge, can mathematically unlock the distance from earth to the sun, and thus the size of our solar system. For 17th & 18th century transits, intrepid explorers set out to answer a leading question of mankind. Not all of them made the voyage back home.
Mystery of "Black Drop"Just before or after the circular black dot of Venus seems to touch the edge of the sun, a peculiar "black drop effect" sometimes occurs between the contact points. A ligament of darkness smears the juncture of Venus and the sun. You can see a similar anomaly if you almost pinch your thumb and forefinger together. Just before you sense contact, a black feature spans your two digits.
Transits Lead the Hunt
Once again, transits are on the leading edge of new discoveries. The NASA Kepler mission and others are using the transit method to find habitable planets around distant stars. The Kepler spacecraft monitors over 150,000 stars, looking for periodic dips in their light curves which reveal the presence of companion planets. You, too, can join this quest for new worlds.
Midwest Treasure: TROVE
Art exhibits, family activities, a bus tour, historic artifacts, lectures, webcasts, telescope viewing, and more complemented the visual spectacle near the Michigan-Indiana border. This hub of 2012 transit of Venus activity in Michiana celebrated the math, science, history, and art of the celestial phenomenon.
- Poster: Transit of Venus Time Keg
- Community Celebrates
- Closure for Transit of Venus
- Vision For Future
- Video Follows Michiana Experience
- Transit of Venus Time Keg
- Viewing Great, Timing Difficult
- Time to Set Sail
- What if it's cloudy?
- You Can Learn a Lot From a Dot
- Can I Use Welding Glass to View the Sun?
Chef and restaurant owner Steve Stogdill roasted Black Drop Effect Bistro Coffee to be "characterized by high grade beans, heavy body, and low acid with a special finish on your palate." Living up to its name, the coffee is very dark, yet Stogdill notes, "Dark coffee does not need to be bitter, and this proves that."
In 1999 the TRACE spacecraft imaged a transit of Mercury, from which astronomers determined the black drop effect is not a function of atmosphere but more a function of the telescope optics and of solar limb darkening. See the black drop effect FAQ.
The Black Drop Effect Bistro Coffee label pays tribute to the stained glass window of St. Michael's Church in Hoole, England, where Jeremiah Horrocks first recorded a transit of Venus in 1639. In subsequent centuries the church has commemorated the historic sighting and Horrock's character with architectural details such as the stained glass windows. Each pane is filled with an image related to the transit of Venus. The text within the banner, Come Sip or Ship, invites patrons to enjoy the coffee at Victorian Pantry or to purchase the coffee and have it shipped.
An 11-ounce foil pouch of coffee, whether whole bean or ground, costs $11.99 USD plus shipping. To place an order, email Chef Steve at CLOAKING .
- Full dome digital video about the transit of Venus.
- Personal introduction to Transit of Venus and safe viewing techniques.
- Transit of Venus in Pastel art exhibit.
- Historical artifacts on display, with emphasis on USNO expedition photographer from Indiana.
- Live program at Notre Dame Digital Visualization Theater.
- NASA webcast from Hawaii.
- Telescope observing of first and second contacts of Venus against the sun.
- Sunset with the transit underway, while overlooking beautiful Lake Michigan.
- TROVE Art Exhibit
- Venusian ale at The Livery microbrewery
- Transit of Venus send-off party with live music and camaraderie of ToV enthusiasts.
- Round-trip transportation on exclusive motor coach.
Fine Print:Viewing the sun without proper equipment and/or techniques can result in serious eye injury and blindness. The solar observing descriptions and comments listed in this website are not an endorsement of any particular technique or product. Observers are responsible for their own eye safety. This website accepts no responsibility for the conduct of others in viewing the sun.
For definitive advise on observing the sun, see Viewing the Transit & Eye Safety, by Dr. B. Ralph Chou, at http://www.transitofvenus.org/june2012/eye-safety/280-viewing-the-transit-eye-safety.
"It is never safe to look at the sun without proper eye protection. No filter should be used with an optical device (e.g. binoculars, telescope, camera) unless that filter has been specifically designed for that purpose and is mounted at the front end (i.e., end towards the Sun). Unsafe filters include all color film, black-and-white film that contains no silver, photographic negatives with images on them (x-rays and snapshots), smoked glass, sunglasses (single or multiple pairs), photographic neutral density filters and polarizing filters, computer disk media. Most of these transmit high levels of invisible infrared radiation which can cause a thermal retinal burn. The fact that the Sun appears dim, or that you feel no discomfort when looking at the Sun through the filter, is no guarantee that your eyes are safe. A person with eye damage from improper viewing may not notice the damage until hours later."
For observers who refuse to view the sun safely--Leader Dogs for the Blind in Rochester, Michigan.
Join the Hunt for Treasure!
[Note: though the opportunity to get free solar shades ended May 31, artifacts remain on display until after the June 5 transit of Venus. See TROVE Adventure map for the list of sites.]
Notre Dame Community Relations
Glance Eyewear Gallery
View TROVE Adventure in a larger map with list of sites
Here are the treasure hunting tools you need to find Keywords at each site:
- Map of the TROVE Adventure treasure hunting grounds in Michiana:
- List of participating TROVE Adventure sites with space for you to write each Keyword.
- List of questions that can be answered from clues at the sites.
Dr. B. Ralph Chou, author of Viewing the Transit & Eye Safety, notes a shade number 14 welder's glass provides suitable protection. However, this type of glass is becoming less readily available and is now a special order item. Importantly, polycarbonate welding filters now on the market are not sufficient unless they have gold coating. Polycarbonate filters without gold coating protect from high levels of visible light but are highly transparent of infrared.
It is imperative that the welding hood houses a #14 or darker glass filter. Do not view through any welding glass if you do not know or cannot discern its shade number. Be advised that welders typically use glass with a shade much less than the necessary #14. Just because the hood makes the sun somewhat more tolerable to see does not mean the welding glass is of the proper kind.
The view through a proper #14 welding glass (left) shows only the sun, which will appear green. The surrounding landscape is not visible.
A welding glass that is less than shade #14 allows too much light to pass. In the picture at right, an insufficient welding glass permits so much light to pass through that the landscape can be seen. This view is not safe.
- Artifacts at Harris Branch Library in Granger, IN
- Pizza Transit
- Video: The Transit of Venus
- Sermon Suggested by the Transit of Venus
- You Can Learn a Lot From a Dot
- Order Bulk Solar Shades
- Solar Eclipse Sunset: Lake Michigan on May 20
- Arise, Ye Artists, For Ale and Astronomy
- Time Keg Seeks Your Imprint
- Galileoscope Solar Filter
- AstroFest in South Bend on April 28