Construct a device that will help you aim your telescope at a celestial target in the night sky. <\/p>
T<\/span>his project helps you aim your telescope at a target in the night sky.<\/p>\n It is called a zero-magnification finder because the view is the same size as seen with your naked eye.<\/p>\n The finder projects a red circle onto the background sky and you move your telescope to align the centre of this circle with your target.<\/p>\n Many stargazers use similar devices because they allow you to keep both eyes open and see a much larger area of sky, making it easier to jump to the target.<\/p>\n Our design has a red LED that illuminates the white interior of the front of the case.<\/p>\n The LED is powered by a coin cell battery, via a switch on the back panel.<\/p>\n The red light is reflected backwards through a clear glass screen, painted matt black except for a small ring in the centre.<\/p>\n The light is then reflected upwards by a mirror mounted at 45\u00b0 and through a lens, which produces a sharp image.<\/p>\n This is reflected backwards again by a glass viewing screen, mounted at 45\u00b0 in a hood.<\/p>\n When the distant sky is viewed through this screen, the red circle is superimposed on it.<\/p>\n We sourced the components for this project imaginatively to keep the cost down.<\/p>\n The LED, coin cell holder and switch are from an educational supplier.<\/p>\n The clear glass was cut from an old picture frame, and we used the frame\u2019s thin MDF backing to make the case.<\/p>\n The front surface mirror is a disposable dentist\u2019s mirror. We found these online, along with the lens, a Fresnel magnifier sheet.<\/p>\n Cutting glass is easy \u2013 score with a glass-cutting wheel and snap over a straight edge \u2013 but it is advisable to dull the resulting sharp edges by rubbing on a flat stone.<\/p>\n Alternatively use clear plastic, which can be cut from an old CD case.<\/p>\n Once you have made your finder, you\u2019ll need to mount it and align it with your telescope.<\/p>\n We used a camera ball mount for this. The top screw passes through a hole in the bottom of the case.<\/p>\n Use a \u00bc-20 nut to fix it. Alternatively, a blob of hot glue will suffice.<\/p>\n To attach the ball mount to the scope, use a \u00bc-20 stud (some mounting rings have screw-threaded holes for attaching accessories), or improvise with a large pipe clip or cable ties to hold the hot shoe part of the ball mount.<\/p>\n Point the scope towards an easy-to-find bright star or planet, loosen the ball mount and align the projected red circle with the same target.<\/p>\nHow it works<\/strong><\/h2>\n
Getting the materials<\/strong><\/h2>\n
How to mount it on your telescope<\/strong><\/h2>\n