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with the 160EDF refractor on the Mach2 mount. The comet head was
tracked using the Keypad Drift Model. I took one data point on the
comet's nucleus (a 4 minute drift measurement), then turned on the Model
to begin tracking the comet. I took a total of 40 images of 30 sec each
thru LRGB filters over a period of about 1/2 hour until the comet
dropped below my observatory walls. The background stars moved
approximately 1/2 way across the frame during that time while the comet
stayed stationary on the chip. Seeing was good but transparency was
unfortunately poor with thin high clouds.
Tracking comets can be done two ways, with APCC Horizons and now with the keypad custom model. Using Horizons with emphemeris data takes a bit of doing, and is suited for permanent setups. The keypad drift model is very quick and quite accurate and can be done in a field setup in just minutes.