Stellar
Products Adaptive Optics
(Updated May 2014)
Once I learned about the idea of adaptive optics,
and studied the theoretical improvement in imaging that would result from only
tip-tilt correction, I started the design of an inexpensive system that would
work in visible light for small apertures.
Using analog circuits and a large area silicon quad cell, I found I
could stabilize the brighter planets with a 20 Hz bandwidth. Since virtually all astronomical photography before
1995 was done using film, exposures were typically 5 seconds to 30 seconds
long. The device had to not only
stabilize image motion due to atmospheric tip and tip, but also correct mount
tracking errors. Based on this approach,
I used voice coil actuators and a 2-D flexible coupling that supported a small
lens. A cube beamsplitter was used after
the lens to sample the image motion for the analog control loop. I called it the “AO-2”, since it had two
degrees of correction.
After testing it with a small telescope, I started
to get publicity. Reports and news
articles are free! My first one was in
“Laser Focus World”, an optics trade magazine. I later met editor
Dennis Di Cicco at an astronomy conference in
Wisconsin, and he offered to test the unit and show it in the premier U.S. astronomy
magazine, “Sky and Telescope”. A
Japanese dealer also was able to get me into some of their magazines. Later, the Japanese equivalent of PBS made a
television documentary about their National Subaru telescope, and put in some
of my video images of a rotating Jupiter.
When Comet Shoemaker-Levy 9 collided with Jupiter in
the summer of 1994, I was prepared. The
seeing in San Diego was good, and there are always clear skies. I used the finest grain slide film and took
lots of photos when the word came out that the comet caused black spots to
appear in the clouds. I was the only
amateur astrophotographer to get good images of the
black spots, and the only one I know that was able to image the Great Red Spot
at the same time. This accomplishment
garnered my photos the front cover on several magazines, and nice placement in
some Japanese magazines, as well as “Astronomy” and the Italian “Orionis” magazine.
Meade Instruments sent me their new CCD camera (I helped them debug the
software) in exchange for allowing them to use my photos in their advertising,
including their annual catalog. All of
these pre-date the growth of the Internet, and was the main approach to
advertising.
While I was manufacturing the AO-2, I knew that a
higher-order system would be useful for larger telescopes. I developed the AO-5, which corrected tip,
tilt, defocus, and two orthogonal astigmatisms.
For this, I needed the new CCD cameras and wrote a digital control loop
that operated on an IBM PC with a clock-doubled 66 MHz i486-DX2
processor. This computer was fast enough
to keep up with reading a small region-of-interest in the wavefront sensor
camera, calculating the appropriate voice coil voltages, and sending those
commands to a digital-to-analog output board.
The system worked well in lab testing and was delivered to the customer,
but due to the passing of one of the key users, the system was never tested in
the observatory. I am currently building
a more compact unit with modern CCD sensors that can be used with commercial
16”-28” telescopes, and will operate with a much, much faster computer.
Several
papers were generated for this prototype, and new papers will be written about
the latest prototype and results on a 16” telescope.
Tesla
Coil Paper and High Voltage Projects
Laser
Experiences at Hughes Aircraft and Kaman Sciences
Weather
Station Papers and Remote Sensing Experiment