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Correcting for Magnetic Declination Error on the GPS Models

This tip comes from a combination of tips from Carol Price and Oliver Sanguy as posted on the Yahoo NexStar GPS group.

One of the difficulties you might experience using the GPS alignment feature of the NexStar GPS models is that the electronic compass points to magnetic rather than true North.  {This is no longer true if you have hand control version 1.6 or newer - this version introduced the Compass Calibration which deals directly with this issue.  See my review of the new hand control or refer to the manual for details.)  In some areas, the difference can be as much as 20 degrees, meaning that the alignment procedure will miss the alignment stars by as much as 20 degrees.  If you can easily identify the correct star and center it as required, there will be no problem with goto or tracking accuracy, but occasionally, identifying the correct star can be difficult.

You can avoid this problem by forcing the GPS alignment to use true North instead.   After you start the GPS alignment, the NexStar will level the tube and begin to turn towards North.  After the tube is level and while the scope is still locating North, press the Undo button.  Then, release the azimuth clutch, point towards true North yourself, set the clutch again and then press Enter to resume the GPS alignment.   The scope will use your North direction and move on accurately to the first alignment star.  If you miss the opportunity to press undo and manually point North, wait until the scope thinks it is pointing at the first star.  Then release the azimuth clutch, move the scope to point at the first star and reset the clutch.  In either case, you cannot then release the clutch after having aligned on the first star.

Thanks Carol and Oliver!

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