My "Junior Starwatcher" badge.
(47K JPG)
A good source of information about comets is The Comet Observation Home Page at JPL.
A great page of eclipse information is Fred Espenak's Eclipse Home Page at NASA.
I was attending the Small Craft Workshop at Mystic Seaport in June of 1989. Bob Hicks, the publisher of "Messing About in Boats" took my picture and used it on the cover of his magazine. It was quite a surprise when it arrived in the mail.
(70K JPG)
Messing About in Boats is a twice monthly magazine for small boat enthusiasts.
At the Small Craft Workshop in 1997, Bob Hicks took another picture of me standing with my Bart Hauthaway 10 1/2 foot Rob Roy canoe. The picture caption has the wrong lengths of the boats.
The birthplace of amateur telescope making in this country is Stellafane in Springfield. VT. Every summer, 2000 amateur astronomers gather on Breezy Hill for a weekend convention.
If you are interested in old telescopes, then The Antique Telescope Society is the place for you.
The National Space Society has a Boston chapter.
If sundials are your interest, then check out: The North American Sundial Society. For a large list of sundial links, try Sundial Links.
A 296K scan of the Sundicator.
Thomas Spencer obituary
THOMAS DICKINSON SPENCER '34, of Pennington, N.J., died March 20, 1995. He was a retired
commander in the navy who served as assistant naval attaché in Lisbon, Rio de Janeiro,
and Paris and naval attache in Greece. Later he became an insurance broker and estate planner.
He also toured with the musical Oklahoma in the role of Jud, and was joint holder of a patent
for the Sundicator, a navigational instrument modeled after the ancient astrolabe.
A 50K image of a sun tracking device. If you look into the device from the bottom, there is a circular scale calibrated in altitude and azimuth. The sun creates a small bright dot on the scale.
Comets: There is a lot of comet information on the web. A few places to look are: JPL Comet Observation Home Page, and Gary Kronks Comet and Meteor Page
A great page for lunar and solar eclipse information is the Eclipse Home Page . The NASA reference publications on eclipses are available here.
The Harvard-Smithsonian Center For Astrophysics has monthly public open nights, with a lecture and public observing. I've been a volunteer there for the past nine years.
A sample zone plate.
I wrote a C program that generates a Postscript file for a Fresnel zone plate. You can download a postscript file for producing a 31 ring zone plate: zone plate postscript file or as a PDF file: zone plate PDF file
An explanation of zone plates: Chris Patton's zone plate paper at George Smyths web site.
Chris Patton's web site: here
A technical explanation of pinhole optics: Dr. Matt Young's pinhole camera paper
A couple of web resources for pinhole photography are: Pinhole Visions and The Pinhole Resource
Elliptical Pinhole Camera (95K JPG)
(222K JPG)
A 4x5 pinhole photograph from a paper negative made in the elliptical candy tin.
My note on optimal pinhole size
I made a calculator for pinhole camera exposures. You can download it as a postscript file, GIF image, JPG image, or PDF file. Note that I've had trouble getting the GIF images to print at the proper scale and getting the circles to be round. You need to print two copies of the first page and one copy of the second page in order to make the three disks that make up the calculator. So cut out each of the three kinds of disks, cut out the film speed slot on the topmost disk, and assemble with the f/number disk on top, the film speed disk in the middle, and the shutter speed disk on the bottom. To use, set the film speed, and then holding the top two disks, rotate so the pointer points to the light brightness value. Brightness values are the same as on the Luna Pro exposure meter. 20 is bright sunlight.
A postscript file for a pinhole photography exposure calculator
exposure calculator page 1 gif file
exposure calculator page 2 gif file
exposure calculator page 1 jpg
exposure calculator page 2 jpg
exposure calculator as a PDF file
Click on the thumbnails for an enlarged view.
The Stereo Realist Camera.
The Sanford Camera Repair rewind crank.
Note: some individual cranks don't fold down easily due to the tight fit between the parts of the crank.
The Sanford flash unit on the camera.
The flash unit by itself.
