Actual Step

5c: Artificial Star Collimation

updated: 2024-04-17


In the final stage of the process, the telescope's optics are refined using a real or artificial star. This enables the stars to appear as points again, rather than as distorted or elongated blobs.

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Gear Installation an Calibration (Northern Hemisphere)

The advantage of this method is that it can also be carried out during the day and in closed rooms. 

The disadvantage of this method is threefold:

  1. An artificial star can never simulate a real star, because you have to use a completely different focuser setting (and add more extension equipment as usual) to adjust the focus point of the telescope to the relatively short distance to the artificial star.
  2. You need at least 20 m distance to your artificial star for a good focus - such a distance is often not available.
  3. Whenever you adjust the collimation (or push/pull) screws to move the primary mirror, the artificial star (or even a real star) will move around at high magnification and eventually move completely out of view, which becomes quite boring and you will waste a lot of time realigning the scope with the artificial or real star.

Example image of an artificial star

Image of artificial star's defraction disk, defocused before fine collimation 

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