SharpStar2 from Lonely Speck is a great tool to attain precise focus when taking photos of stars. It is brilliant in its simplicity. It diffracts the light to create 3 fine lines around a bright star, which shift as you focus.
Adjusting focus so the central diffraction spike sits evenly between the other two diffraction spikes will ensure perfect focus.
"The original SharpStar is shown in the video above. SharpStar2 works the same way"
It fits all standard square filter holders in the following sizes:
SharpStar2 is available from the USA and ships within2-3 business days around the world - more information is available from there website lonelyspeck.com/sharpstar/
You can also download a copy of our Quick Start Guide (included with every order).