Celestron 11007, Instruction Manual

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 Polar Alignment (with optional Wedge)

Even though the CPC can precisely track a celestial object while in the 
Alt-Az position, it is still necessary to align the polar axis of the telescope 
(the fork arm) to the Earth’s axis of rotation in order to do long exposure 
astrophotography . To do an accurate polar alignment, the CPC requires 
an optional equatorial wedge between the telescope and the tripod . This 
allows the telescope’s tracking motors to rotate the telescope around the 
celestial pole, the same way as the stars . Without the equatorial wedge, 
you would notice the stars in the eyepiece would slowly rotate around 
the center of the field of view. Although this gradual rotation would go 
unnoticed when viewing with an eyepiece, it would be very noticeable 
when imaging .  
Polar alignment is the process by which the telescope’s axis of rotation 
(called the polar axis) is aligned (made parallel) with the Earth’s axis of 
rotation. Once aligned, a telescope with a clock drive will track the stars 
as they move across the sky. The result is that objects observed through 
the telescope appear stationary (i.e., they will not drift out of the field of 
view). If not using the clock drive, all objects in the sky (day or night) will 
slowly drift out of the field. This motion is caused by the Earth’s rotation.

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 All-Star Polar Alignment  

The CPC hand control has a polar alignment function called “All-Star” 
polar alignment that will help you polar align your telescope for increased 
tracking precision and astrophotography . This feature allows you to choose 
any bright alignment stars to assist in accurately aligning your telescope and 
wedge with the North Celestial Pole . Before using the Polar Align feature, 
you must first perform an EQ North or South Alignment.  
Once your telescope is EQ aligned, slew the telescope to any bright star 
in its Named Star database list . This will be the star used for the All-Star 
Polar Alignment.  For best results, it is always good to choose a polar 
alignment star that is high in the sky and near the Meridian .  Try to avoid 
stars that are close to the west/east horizon, directly overhead or too 
near the celestial pole . 
Press the Align button and use the Up/Down buttons on the hand 
controller to select Polar Align from the list .
The Polar Align feature has two options: Align Wedge and Display Align .
  Align Wedge – After performing an EQ North or South Alignment and 

slewing your telescope to any bright star in the telescope’s database, 
select the “Align Wedge” option .  The telescope will then re-slew to the 
same star . 

    1.  Center the star in the finderscope and press ENTER. 
    2 .  Then accurately center the star in your eyepiece and press 

    ALIGN. The telescope will then “sync” on this star and slew to 
    the position that the star should be if it were accurately  
    polar aligned . 

  For the most accurate alignment it is best to use a reticle eyepiece (see 

Optional Accessories) or a high power eyepiece to precisely center the 
star in the field of view. 

    3.  Use the wedges latitude and azimuth adjustments to place the 

    star in the center of the eyepiece . Do not use the direction 
    buttons on the hand control to position the star. Once the star 
    is centered in the eyepiece, press ENTER; the polar axis should 
    now be pointed towards the North Celestial Pole .

FIGURE 6-3

This is how the telescope 
is to be set up for polar 
alignment. The tube 
should be parallel to the 
fork arm and the mount 
should point to Polaris. 

Updating your Star Alignment

After polar alignment, it’s a good idea to check the pointing accuracy 
of the telescope to see how much it may have been affected by moving 
the mount . Since the polar alignment process requires you to “sync” the 
telescope on a bright star before you begin, it will be necessary to undo 
the sync before re-aligning . To undo the sync:
  1 . Press the Align button and use the UP/DOWN buttons on the hand  

  controller to select Undo Sync from the list, and press Enter . The    
 message 

Complete will display on the LCD .

  To re-align your telescope:
  2 . Slew the telescope to one of the original alignment stars, or another 

  bright star if the original alignment stars are no longer in a 
  convenient location . Press the Align button and use the UP/DOWN 
  buttons on the hand controller to select Alignment Stars from  
  the list . 

  3 . The hand control will ask you which of the original alignment stars 

  you wish to replace. Use the UP/DOWN buttons to select the  

  desired star and press Enter .

  4. Once again, center the star in the finderscope and press Enter .
  5 . Then center the star in the eyepiece and Press Align .
  6. Repeat the process on a second alignment star.
  Display Align – the user can now display the polar alignment error 

in the RA and DEC axes .  These values show how close the mount 
is pointed at the celestial pole based on how accurately the user 
centered the alignment star with the hand control and with the mount 
adjustment. To display the alignment error:

  1 . Press the Align button and use the UP/DOWN buttons on the hand 

  controller to select Display Align from the list, and press Enter .