To prove this idea he brought a photoelectric photometer
attached to a small telescope with an electronic recorder.
By 1952 a photoelectric photometer
was mounted on the Astrographic, though plates continued to be taken and the twin photometric lenses were also in use.
8, 2000 the brightness and color of Saturn was measured with a photoelectric photometer
and color filters.
A solid-state photoelectric photometer
along with Johnson B, V, R and I filters were used.
In 1964 astronomers Alan Binder and Dale Cruikshank reported that observations of Io with a photoelectric photometer
revealed that the satellite brightens temporarily when it emerges from Jupiter's shadow following eclipses.
The observatory closure is primarily due to the author's advancing age and the need to invest into new technologies, the photoelectric photometer
has been mostly supplanted by CCD devices, an expense that the author can ill afford.
What it needs is an amateur-sized scope (or even a camera lens), a good DSLR or CCD camera or a photoelectric photometer
, the right photometry software, and a diligent, thoughtful, persistent user.
About 20 years ago the standard photometric equipment for backyard observers was the photoelectric photometer
. This is a very sensitive vacuum-tube light meter that requires a bulky high-voltage power supply, amplifier, and data-recording device.
While parts-per-thousand brightness measurements are challenging even to professional astronomers, "a serious amateur [with a photoelectric photometer
or a CCD] should be able to make a measurement" of the newly discovered brightness dips, says David W.
My own adventures started in 1979, when I measured bright stars with a small telescope and homemade photoelectric photometer
. This pursuit has increased my understanding of the way the universe works.
Today, precise magnitudes are specified by what a standard photoelectric photometer
sees through standard color filters, which are depicted above.
Using a 1-meter telescope equipped with a photoelectric photometer
, students can view about 70 stars in the Pleiades and measure their magnitudes in the U, B, and V color system.