To accurately test and collimate telescopes, reflectors, catadioptric, and refractors, you must perform a star test. However, to do so, you need a star. Sadly, a real star is not always available due to poor weather conditions or location. Even when a star is available, you will need a good tracking system for doing star test as the star is always moving. Also air turbulence may affect your test, and the real star may not even reveal the true quality of your telescopes or give you a perfect collimation.
An artificial star is an excellent alternative. With an artificial star, star tests can be accurately conducted anytime and anywhere. However, the problem with a single artificial star is you need different telescopes require different star sizes, depending on the telescope’s aperture, and focal ratios. Even the same telescope when setup at different distances, and under different lighting environments, can require diffent star sizes.
Hubble Optics 5-star Artificial Stars features five bright white LEDs with 5 precision pinholes (50/100/150/200/250 microns). This enables you to star-test virtually any telescope, regardless of aperture size, focal ratio, distance, and lighting conditions. Simply choose the smallest possible star that still provides a clear and defocused image.
You can even adjust the brightness of the stars by twisting the LED cap!
And, you can mask any four of the five stars with the provided magnetic mask.
A clever solution, well executed.