AWR Logo



Skysensor 2000
10 inch Newtonian
SuperPolaris mount
A regular pattern of dots is perfection. The aspect ratio (vertical scale to the horizontal scale) may be different but it should still be regular. It is formed by the star staying at the node for a few seconds before you press the button to move it on to the next segment. The camera shutter is open throughout the exposure. The RA direction is horizontal.

Defects show up as irregularities, look a the corners. Those going to the top right edge of the photo are correct. The top left corners have a problem in that the RA seems to be driving backwards a constant amount when the DEC button is pressed. The bottom left corners are nearly correct but the RA length is short immediately out of the corner. This should not be possible as the RA motor is following the stars when it goes down the previous edge. The bottom right corners have grossly shortened DEC movements which could be backlash being taken up. The right hand edges are also not straight, possibly showing up periodic error.

The scope was a 10 inch Newtonian on a Superpolaris mount driven by a Skysensor 2000. After several attempts to improve the situation we decided to do a complete factory re-boot by pressing all four direction keys at once at power up. Lo and behold! it sorted the problem. The mount was being told to move in these weird ways.


January 2005 AWR Technology 01304 365918