Contents - Index

Unguided Operation

During unguided operation, the same benefits that accrue during Guided Operation can be achieved.  Here, the mount is moved slightly between exposures.

Dithering can be done either totally randomly, as determined by a random number generator, or in a controlled manner to maximize separation between each sub-exposures artifacts while minimizing the overall guide star movement. Both options are provided. The amount of the dither is user-definable.  Here is a discussion on how to set the amount of dithering.
  • Dither method: Select Enhanced (preferred), Random or None.
  • Max. Pixel Dither: This is the peak dither value and can go +/- from the starting direction. As an example, suppose Enhanced Dithering is selected with a Max Dither of 3 arc-sec. The first sub-exposure will leave the mount position undisturbed. The second will move the mount +3 arc-sec. in RA. The third will move the mount - 3 arc-sec.from the first exposure. Thus the total movement between the second and third exposure is 6 arc-sec. but the movement relative to the first sub-exposure is 3 arc-sec. If dither is set to 0,the mount will not be moved between exposures.
  • Suggest: this button will enter a Max. Dither value, based on the parameters of your system entered on the settings page. This can be a starting point from which you can experiment if you desire.

    Periodic Realignment
    When a long series of unguided exposures are taken, the mount will gradually track off the target. By using this feature, the telescope is periodically realigned to the target coordinates. If any periodic focusing using SkyStar is implemented, target realignment will occur during that process. If that is used, additional periodic realignment will occur only as long as the time between SkyStar focus runs has exceeded the realignment period.
    Realign to Target Frequency (min.): If 0 is entered, this function is disabled. If a non-zero value is entered, the telescope will be realigned to the target coordinates via a precision slew after the current exposure completes and after the specified interval has elapsed. It can be disabled (set to 0) when guiding.