Rotator Setup


Rotator COM specifies the serial port that the rotator is connected to.  CCD Commander supports COM ports from 1 to 255.


Home Rotation Angle is the position angle that the camera is at when the rotator is at an angle of 0 degrees.   If the top of the detector is north, then the Home Rotation Angle will be 0 degrees.  If the top of the detector is east, then this value is 90 degrees.  South is 180 degrees.  Finally west is 270 degrees.


Similarly Guider Calibrated at specifies the detector angle where the guider was calibrated.  


The Guider Calibrated at value only applies when the Guider rotates with Imager checkbox is checked.  Guider Calibrated will be disabled when the checkbox is not checked.  If you use a guide scope/guide camera, then you should uncheck this value.  When checked, CCD Commander will automatically recompute the guider coefficients in the camera control program, allowing the guider to function at any desired rotation angle.  When CCD Commander recomputes the guider coefficients for a new rotation angle, the Guider Calibrated at value will be changed.  Since the new coefficients are for a different angle that change needs to be reflected here.  Once you enter this value and successfully use CCD Commander, you shouldn't need to change this value or recalibrate the guider until you make a physical change to your setup.


Finally the Get Angle from TheSky6 button will fill in either or both of the angles (depending on which checkboxes to the left of the button are checked) from the angle of the FOV Indicator in TheSky6.  The easiest way to determine these values and to get them entered it to perform the following steps:


  1. Connect your mount to TheSky6 and slew to a nice star field.

  2. Enable your camera's FOV Indicator in TheSky6.

  3. Take an image of the star field in your camera control program.

  4. Copy the image to your clipboard (either using Ctrl-C or Edit->Copy).

  5. Paste the image into TheSky6 (either using Ctrl-V or Edit->Paste).

  6. Perform an Image Link in TheSky6 to link the image.

  7. The Image Link will adjust the FOVI to the position angle of the image.

  8. Push the Get Angle from TheSky6 button in CCD Commander to pull the position angle from the FOVI.


GEM Users: Note the text on the page specifying what side of the meridian you should be on when getting these values.  If your telescope was on the opposite side of the mount, select the opposite setting in the Mount Parameters tab.


Fork Mount Users: The text specifying the side of the meridian will not appear on this window.


Check the Guider sees a Mirror Image of the sky if the image on the guide chip is mirrored.  CCD Commander needs to know this to rotate the guide vectors in the proper direction.


The Reverse rotator direction check box will tell CCD Commander that the rotator need to be moved in the opposite direction than expected.  See Rotator Physical Setup below for more information.


The During "Move To" Actions that Flip the Mount section defines what CCD Commander will do with the rotator when the mount flips.  When using an external guide scope, it is often useful to not rotate the rotator except for framing.  In this case, the Maintain Rotator Angle (Rotator does not move) option is ideal.  When guiding through the rotator (self guided or OAG) the Maintain Position Angle by Rotating 180 degrees option can be better (but is not necessary).


Rotator Physical Setup

In order to function properly, the rotator must spin in the direction CCD Commander expects.  The rotator must spin in the direction from North to East to South to West.   As you are looking up at the sky, this is a counterclockwise rotation.  You can also confirm the proper direction by Image Linking one image in TheSky6, increasing the rotator angle, and then Image Linking in TheSky6 a second time.  Just like you increased the rotator angle, the position angle of the FOVI in TheSky6 should also increase.


If your rotator rotates in the opposite direction, check the Reverse rotator direction checkbox.