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Anniversary Solargraph

Capture time during the Indiana Bicentennial by tracking the sun between the solstices.

To celebrate the 200th anniversary of Indiana's statehood, make a long-duration photograph that captures the essence of time--the sun's path from solstice to solstice. I encourage Hoosiers to create a solargraph, a months-long exposure of the sun using a simple pinhole camera. Then exhibit the images publicly and online in the Bicentennial year.

Solargraph by ESO's APEX;

Make a Solargraph

There are plenty of instructions online--just do a Google search for solargraph (one word) and select Images. That alone will get you jazzed up. From there, find more instructions or videos. In summary:

Empty a 16-ounce can, cut open the top, make a pinhole in the side, insert and secure a piece of photographic paper, duct tape the open end, tape over the pinhole, and mount the device securely outside facing south. Remove the tape over the pinhole to start the exposure. After several months, retrieve the paper in a dark room or under red light and digitize the exposed image.

I recommend you use 5x7-inch photographic paper, which fits nicely inside 16-ounce aluminum cans. I tried using some larger 23-ounce cans of iced tea with the thought that bigger would yield better resolution, but that requires cutting a full sheet of photographic paper so it fits inside the can well. Instead, support an Indiana business like Bare Hands Brewery, which distributes some of its beverages in 16-ounce cans. Buy a case. Empty the cans somehow (hmm), rinse them out, and let them dry. Cut off the tops with a standard can opener. Spray the inside with flat black paint to minimize internal reflections.

With a sewing needle pinched in pliers, punch a hold from the inside middle of the can outward. [Note added December 2016: After experimenting, I find it best to punch the hole about an inch from the sealed end of the can (leaving room for duct tape or zip ties) and mounting the can vertically.] As an option, gently file down the burr on the outside of the hole, then reinsert the needle to trim the hole again.

In a closet or dark room in your house, arrange your can, duct tape, red light, and photographic paper. Take a piece of 5x7-inch black and white photographic paper and insert it into the can with the emulsion side facing the pinhole. You can tell which side is light sensitive by feeling it with damp fingers. The film side is sticky, whereas the backing is not.

Sunlight coming through pinhole strikes photographic paper in a can to make a solargraph.

On the outside of the can, hold the red light so it shines through the can. Insure that the hole is not obstructed by the photographic paper. Then secure the paper in the can with some tape so the paper does not move if it happens to curl in the ensuing months.

Cover the top of the can with duct tape. I'm a novice, but in my inaugural cans I put three pieces of duct tape over the top of the can, then one banding strip around the end of the can. Add one last piece of tape to cover the hole so no light gets in until the can is secured in place outside.

Mount the can securely outside, with the hole facing south. Months later, cover the pinhole, retrieve the can and and extract the photographic paper in a dark room. In darkness, scan a copy. Note that some printers first do a pre-scan that you can then adjust to size, in which case you want to do the warm-up scan with a piece of scrap paper. The scanner's light will expose your film more, so you only want to scan your paper once.

Finally, flip the image and invert the colors. You can then image-process and contribute to the collective effort.

The image at the top of this page and a good description of what is happening on the film is credited to authors ESO/R. Fosbury/T. Trygg/D. Rabanus.

Participate in a Collective Snapshot

Join a collective effort to take a snapshot (albeit it a long one) of time during the Indiana Bicentennial. If you're going to do one, you might as well make several. Buy photographic paper in larger quantities at a photo supply store like Gene's Camera Store in Mishawaka and South Bend, IN. Host a party or public event where you can turn down lights and use only red headlamps and red flashlights. Then make a bundle of solargraph cans and experiment with locations.

See for public event to make Anniversary Solargraphs on Thursday, June 16, at 7 PM at the Centre Twp. Branch Library during the regular meeting of Michiana Astronomical Society Inc.

Be sure to label each can with the participant's name, contact info, date exposure begins, and a link to this page, While a 6-month exposure between the solstices will yield the greatest area of the sun's path, you can try making a solargraph for more or less time. Experiment!

Bicentennial Display

I invite you to send your digital images to me after you have processed them. Include your contact information and how you wish to be credited so I can attribute any display of your image to the proper source. I will post the solargraphs online as a collection of Indiana Bicentennial images. In the interim, will also try to secure a site at which a hard copy of solargraphs can be publicly exhibited. Thank you for your consideration.

Take the Next Step

Taking a solargraph is one step toward getting a better understanding of and appreciation of the sun. From there I invite you to investigate other sun-seeking opportunities. To advance the solar economy in Indiana, we need to know and to embrace the sun. Witness and understand the natural order to get perspective on how we can use it. Later I'll be posting ideas and activities to launch your inquiry.

In the interim, prepare for the 2017 Solar Eclipse. It will likely be the most observed celestial phenomenon in US history, and, if you travel to the swath of totality, the sight of a lifetime. Strap yourself in and get ready for the ride.


October 27: Solargraphs Capture School Vista as fourth-graders mount six cans around their school grounds.

October 19: Anniversary Solargraphs are featured in One Orbit Later poster for Great Lakes Planetarium Association 2016 Annual Conference.

October 12: Solargraphs are feature of the Indiana Bicentennial Birthday Bash at Bendix Woods County Park. Concurrently, we observed the sun with telescopes safely.

September 8: At Bendix Woods County Park, site of the Bicentennial Birthday Bash, are two solargraphs along the Bicentennial Torch Route.

August 30: Sometimes solargraphs don't come out well, which is discouraging. See Solargraphs Awry.

July 12: Solargraph cans are mounted at the historic JD Oliver Mansion and JMS Building in South Bend. See Historic Sites Support Legacy Project.

July 11: Indiana Bicentennial Commission endorses Anniversary Solargraph as an Indiana Bicentennial Legacy Project.

June 22: More cans added to St. Piux X Catholic Church and to Four Winds Field. See blog post Solargraph Sites for Players and Prayers

June 21: On the solstice we started setting out cans both vertically and horizontally. See blog post Time Starts on the Solstice.

New tag: solargraph.

June 14: Thanks to Ball Corporation in Monticello, IN, for donating 16-ounce cans to support the Indiana Bicentennial.

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