Collimation: Newtonian/Dobsonian, by Keith Venables


When looking at stars through your telescope, do they appear large and distorted instead of perfect points of light?  While sometimes this is the atmosphere, quite often it is because one or more optical components in your scope are mis-aligned!  This can also waste light coming from your primary, resulting in dimmer views of objects.

This class will show you how to collimate your Newtonian/Dobsonian telescope without using a laser.

You’ll learn the basic principles of collimation of the focuser, secondary mirror positioning/offset, and primary mirror center marking.

It will cover various methods including the use of an affordable “Cheshire Collimating Eyepiece”, and the use of a “star test” at night to really optimize your telescope’s performance.

We’ll also show you how to use TSP SCURT and artificial star to check your equipment.

Subject to his other TSP commitments, Keith will subsequently be happy to help class attendees at night to perfect their star tests.


Suitable for absolute beginners, plus anyone wanting a refresher


Daytime session (1 hour)

Tuesday May 12, 2015 10:30-11:30 AM