We installed two photometers in Alaska. One was installed in Poker Flat Research Range, near Fairbanks, and the other was installed in the Fort Yukon Air Force Station, in Fort Yukon.
We installed the instrument at Poker Flat Research Range near Fairbanks, first.
The instrument was installed beneath a glass dome on the roof of one of the buildings. As you can see,
there are many other instruments installed here.
Under the dome we have installed the Telescope that is aligned with the incoming
magnetic field lines for this location. We do that so that it will look directly up the ribbons of
Aurora that occur overhead. The Telescope focuses the light onto the end of the
Fiber Optic Cable which brings the light down to the photometer itself. There are
two Sun Sensors that
measure ambient light levels and tell the instrument when it is time to
start collecting data. (when it is dark). The Video Camera is used to
get an overall view of what the sky is like during the night. The Fan Outlet
helps to keep the dome from fogging up. The Thermistor is used to measure
the temperature of the dome area.
Below the telescope, inside the building, is where the photometer and other electronics are installed.
The light comes down the Fiber Optic Cable and through the Filter Wheel. We have four different
filters in the Filter Wheel to allow us to look at different wavelengths of light. We have 4278, 6300, 8446, and 8714 angstrom filters.
After the light goes through the filter, it enters the Photometer which turns it into electronic pulses.
The Photometer has a Cooler that keeps it at -30°C. This allows it to be
very sensitive to low levels of light. The electronic pulses go through the Electronics box and on down
to the computer to be counted. The 28V Supply supplies power to the high voltage circuit on the
photometer which generates 1800 Volts for the photometer. The 5V Supply generates power that is used
by the Electronics and the servo motor that turns the Filter Wheel.
The computer is in a room below the photometer. It collects all the data, and controls the rest of the instrument. The computer automatically updates the web page each morning with the data from the previous night. A UPS is attached to the computer to filter the power and protect from short power outages.
After installing the instrument in Poker Flat, we flew to Fort Yukon to install the second instrument.
The second instrument was installed at the Fort Yukon Air Force Station. The station exists to run a long range radar system for the Air Force.
We stayed at the living quarters of the Air Force station itself since there are no hotels or restaurants in Fort Yukon. It is very nice and the food was good too.
The Instrument was installed in a hut on the station that is owned by the University of Alaska.
The dome on that we used on this hut is a bit different than the one at Poker Flat. Instead of a dome shape, it is a half cylinder.
This works fine for us since we are only looking at a few degrees of the sky. The telescope used here is different too. This one was originally
designed to be mounted out of doors so it is weather proof and has internal defogging capabilities. We aren't using the
defogging system here.
The Photometer and electronics are installed directly below the dome. This part of this instrument is identical to the Poker Flat one so I won't explain what each item does here. See above for that.
The computer in Fort Yukon is installed in the room next door to the instrument. The cables run through a hole in
the wall behind the computer. The software is identical. It controls the system and makes the data web pages automatically.
