This page last changed on Dec 02, 2012 by rp7772.
Slewing to objects:

With the viewfinder correctly set it should be easy to find brighter objects through the telescope.
First, identify the star with the aid of a star chart, Stellarium or Worldwide Telescope. Next, it was found that it was helpful while slewing the telescope to the object, to look through the viewfinder but keep the other eye open too and looking at the sky. This way it is easy to line the viewfinder up with the desired star. Once it is in the viewfinder's field of view it can be easily centred with the crosshairs, at which point it should also be in the telescope's field of view if the viewfinder is calibrated correctly.

Aligning the Telescope for Tracking:

Theoretically, if the base of the telescope is entirely level, then only 1 star's position is required in order for it track the sky effectively. The LX200's mount is set up to be level although it was found that the 1 star alignment procedure (TELESCOPE>ALIGN>ALTAZ>1 Star) was not as successful at maintaining good tracking than the 2 star procedure (TELESCOPE>ALIGN>ALTAZ>2 Star Alignment).

Results were also best when choosing two stars that were further apart on the sky.

To set up tracking with the CCD in place (this is preferable to aligning with the viewfinder and changing as you eliminate the possibility of upsetting the alignment in changing the viewfinder):

  • Put the CCD in 'focus' mode from CCDOps.
  • Set the resolution to a lower setting so that the image on screen updates as quickly as possible.
  • Using a slow slew speed, centre the first alignment star after selecting it in the alignment procedure.
  • Watch which direction the star drifts when left unattended and slew the telescope a little in the opposite direction.
  • The tricky bit is to then press 'ok' when you feel that the star has moved to the centre of the field of view. This is only made difficult by the speed at which the image updates on the computer. It takes some getting used to, though becomes easy after a few attempts. It helps to time it right so that the star is at the centre of the frame as the CCD captures the frame. You then receive validation that you pressed 'ok' at the correct time after the frame downloads and the star is in the centre.
  • Repeat for the second star.

You should now have fairly good tracking. Test it out by slewing to a star you know from the catalogue (such as Betelgeuse or Sirius). It's also important to frequently check the slewing and tracking so as not to accidentally take images of the wrong star by trusting the telescope's coordinate system.

In the event of frequent or particularly stubborn slewing errors, you may want to consider using a shifted coordinate system method.

Document generated by Confluence on Jun 12, 2013 09:50