Byers Cam Trak Contents | Cam Trak Components | Tripod Assembly | Tracker Setup | Polar Alignment |
Final Polar Alignment
The Cam Trak includes a 1x (non-magnifying) polar alignment "scope" which projects a target pattern on the sky as seen at right. Do not place your eye up against it as for an eyepiece, but instead, view from a few inches back. The intensity of the reticle pattern may be adjusted by turning the potentiometer at the base of the polar finder (east side of the mount). For maximum accuracy, you must determine the position angle of Polaris relative to the celestial pole and place it in the space between the reticle circles at the calculated angle. When this is done, the red dot at the center is where the celestial pole is located, and the mount has been aligned. For some Cam Trak units, a plastic circular slide rule type calculator was provided to facilitate calculating the position angle of Polaris. If this is not available, use the chart at right to roughly determine the position angle. The key relationship is the line between the end star of the Big Dipper's handle (Alkaid/ Eta) and Epsilon Cassiopeia. Polaris is very nearly on that line, displaced towards Cassiopeia. So to use the chart, rotate it until the positions of the Big Dipper and Cassiopeia match the actual arrangement in the sky, determine the line described above, and note the proper position of Polaris as it should appear in the reticle. Now fine tune the position of the tracker to place Polaris in the reticle annulus in the position determined from the chart. Once Polaris is positioned in the reticle to match, the Cam Trak is polar aligned. For fine adjustment of azimuth to achieve polar alignment, loosen the spring-loaded center screw holding the tracker to the tripod and carefully rotate the tracker on top of the of the tripod. Use the adjustment knob at the north end of the tracker to make fine adjustments of the altitude.
Note: If you have not taken astrophotos with a tracking mount such as the Byers Cam Trak, see "A Quick Start Intro to Wide Field Astrophotography" for some tips to get started. |
D. Kodama © 2003 |