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Auto Two Star Align

Introduced with NexStar hand control version 2.3 (first shipped with the NexStar 8i SE) and available in all newer versions, Auto Two Star Align is a cross between the original NexStar Auto Align and Two Star Align.  With Auto Two Star Align, after entering the date, time and location information, you select a star from a list of the brightest stars currently above the horizon.  You must then manually slew to that star.  After centering the first star the telescope will then automatically slew to a second alignment star.  After centering the second star the scope is aligned and ready to go.

Procedure:

  • Power up the scope.
  • Press ENTER to begin, use the Up and Down buttons (6 and 9 on the keypad) to scroll to Auto Two Star and then ENTER again.
  • The hand control will show either the current time or the time when you last used the scope.  The top line of the display will cycle through the messages, "Enter if OK", and "UNDO to edit".  If your scope has a GPS module, the GPS receiver will shortly lock onto 3 GPS satellites and update the date, time, and location.  If you become impatient waiting for a GPS link, or if you don't have a GPS module in your scope, use the Up and Down buttons (6 and 9 on the keypad) to scroll through the date, time, and location settings. If they are all correct, press Enter to accept and proceed with the alignment.  If they need adjusted, press Undo and make any necessary corrections.
  • The display will now prompt to Select Star 1.  Decide which star you will use, Up and Down buttons (6 and 9 on the keypad) to scroll to that star and then press ENTER.  For Northern Hemisphere use, Polaris (the North Star) is an excellent choice.
  • Use the arrow buttons to slew (move) to the star you selected.  Center the object in the finderscope and press ENTER.  Then center the object in the eyepiece and press ALIGN.
  • The scope will now automatically slew to a second alignment star and prompt you to center and then align, just as you did with the first star.  If this second alignment star is obstructed from view or if you would like to use a different star to get wider separation from the first (which improves GoTo accuracy), press Undo to skip to the next available star.
  • After pressing ALIGN for the second star, you are finished.

Additional details:

  • Auto Two Star Align is only used in alt-az mode - mounted right on top of the tripod.  When mounted equatorially on a wedge, the original Auto and Two Star Align, as well as the new One Star and Solar System Align (hand control version 4 or higher) are available.
  • As with all the new NexStar alignment methods, Auto Two Star Align does not care where the optical tube is pointed at the beginning of the alignment.
  • To get closer pointing for the second star, be sure to level the tripod before you start.  Once the alignment is complete, GoTo and tracking are not dependent upon the accuracy with which you leveled the tripod, so do not spend time seeking perfect level - close is good enough.
  • If you do not have a GPS-equipped telescope, be accurate to within a couple of minutes when entering the time.  Also, either select a city within 50 miles or enter your longitude and latitude to within a degree or two.
  • It is still important to select widely placed stars for alignment.  When selecting your first star, keep this in mind.  Selecting a first star high up in the sky will limit the possible separation of the automatically selected second star.
  • Be sure to center the objects with the same final movements as the direction of the GoTo Approach.  For example, if the scope normally finishes a GoTo with the front of the scope moving right and up, you will center both alignment stars in the eyepiece with the right and down arrow buttons (the up/down arrows reverse at slew rates of 6 or lower).  For more details on this, refer to my book The NexStar User's Guide or the other general alignment guides found here on my web site.

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