Geoptik Artificial Star - White LED - For Telescope Collimation and Testing ... variable brightness

Artificial stars allow you to collimate a telescope perfectly without having to wait for a perfect night. A particular advantage is the possibility to reduce or even eliminate the distracting influence of atmospheric turbulence by setting the star and the telescope up inside a closed room.

No Need For Night-Time Telescope Collimation Anymore!
It almost sounds too good to be true, but this is exactly what you get with the Optik Star. This device is not a simple home-made device. It has a very precise and small 50 micron hole.
Specifications:

• high precision artificial star with 50 µm diameter
• sturdy housing with on-off switch
• easy to set up (on a wall or a tripod)
• needed battery: 9V block (6LP3146)

White LED
The Optik Star uses a neutral white LED which allows you to detect and judge the colour correction of your refractor. It is also suitable for testing telescopes without chromatic aberration, e.g. Newtonian telescopes.


Practical Tips :
In order to collimate a telescope or to detect optical aberrations such as astigmatism or coma you need only a short distance between the telescope and the artificial star. In these cases due to the extended focal plane you may need extension tubes in order to reach focus. We offer extension tubes of various lengths (see recommended accessories).

Spherical aberration is very difficult to detect using an artificial star. You should set up the star at a much greater distance from the telescope. We recommend a distance in meters that is equal to one third of the aperture in millimeters. For instance, for a telescope with 200mm aperture you should set up the artificial star at least 66m away from the telescope. For precise star testing we rather recommend using a real star, especially if you not only want to detect whether or not an aberration is present, but also wish to estimate the magnitude of the aberration.