Hubble 5-star Artificial Star The star test is the ultimate method to test and collimate all telescopes, incuding the Hubble Space Telescope Hubble 5-star Artificial Stars will provide you an excellent alternative mean to do the star test anytime and anywhere you want. without all the drawbacks of the real stars. You can instantly find out which star is best for your particular telescope at that particular distance under that particular lighting environment by simply choosing the smallest possible star, but which still give you clear defocused image You can even adjust the brightness of the stars by twisting the LED head. You can mask out any 4 of the 5 stars with a provided magnetic mask.