SkyAlign
Introduced with NexStar hand control version 4 (first included with the CPC) and available in all newer versions, SkyAlign is an entirely new approach to aligning an alt-az mounted
telescope. SkyAlign requires no knowledge of the night sky and as such
is designed for beginning backyard astronomers. In a nutshell, you set
up the telescope, provide your location and the date and time (GPS-equipped
models will automatically retrieve this information from the Global
Positioning Satellite network) and center 3 bright objects (you don't even
need to know their names) in the eyepiece.
The scope is now aligned and ready to Go(To).
Procedure:
- Setup the scope in alt-az mode - mounted right on top of the tripod.
SkyAlign is not currently available when mounted equatorially on a wedge.
- Power up the scope.
- Press ENTER to begin and then ENTER again when the display reads
SkyAlign.
- 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.
- Next you will see a short message about what will happen next - press
ENTER to continue.
- The display will now prompt to Center Object 1. Prior to
beginning, you should scan across the sky looking for three bright points.
Two of them need to have wide separation, the third should not be close to
the line connecting the other two.
- Use the arrow buttons to slew (move) to the first of your bright
objects. Center the object in the finderscope and press ENTER.
Then center the object in the eyepiece and press ALIGN. Repeat for
two additional objects and you are finished.
Additional details:
- As with all the new NexStar alignment methods, SkyAlign does not care where the optical tube is pointed at the beginning
of the alignment.
- Be sure to level the tripod before you start. Assumptions about
the available bright stars and planets rely on a level tripod.
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.
- Only stars of magnitude 2.5 or brighter are included in the SkyAlign
procedure, so it is best to take a look around and select three of the
brightest stars in the sky.
- No need to worry about confusing planets for stars - SkyAlign works
with the four brightest planets as well (Venus, Jupiter, Saturn and Mars).
Also, you can even use the Moon as one of your alignment objects - though
due to the speed with which it moves across the sky and the size (you
would need to switch to a low power eyepiece to center it), it is
recommended you avoid it when possible.
- It is still important to select widely placed objects for alignment.
When scanning the sky before you begin, keep this in mind. Only two
of the objects (the two with widest separation) will actually be used for
calculating the model of the sky. The third object is needed to
provide a positive identification of the other two. So, be sure at
least two of the three are widely spaced.
- Rarely, SkyAlign will not be able to determine what three objects were
centered. To minimize this further, if you see two bright objects
near to each other (as will sometimes happen as a planet or the Moon
passes near one of the brighter stars) do not use either of these
objects. Also, it is best to select three objects that do not lie on
a straight line.
- 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 all three objects 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 alignment guides found here on my web site.
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