Each pair time/altitude, for one celestial object, gives a line of position. To those not familiar, the altitude is the vertical angle between an object - say a star - and the horizontal. Now that you have your iphone sextant, you need to understand a few facts about celestial navigation.Ĭelestial navigation uses the altitudes of stars, planets, Sun and Moon. The filter must be removable, to allow star observations. If you start to see circular ghosts around, give up observation. A 90 degree prism would be useful, if my eyepiece had one.Īgain, take care with the Sun, even with the best filter. Still, it is a bit uncomfortable to observe the Sun with this sextant, even with the filter, for it has to be pointed directly to the Sun (unlike the conventional sextants, which are pointed to the sea horizon). The shade adapter to the eyepiece tip was made with paper ring and packaging tape ( lame solution ).
A fine sand paper in the glass borders helps. Take care with the recently cut glass, as the border is really sharp. Take it to a glass shop to be cut to suit your eyepiece. The Sun filter I made, shown above, uses dark welder helmet glass ( shade #14 ). Sun light can burn the eye, with nasty consequences. Warning: If you plan to observe the Sun, you need a strong Sun filter for the eyepiece. Use epoxy putty to glue the eyepiece to the frame. The epoxy glue in the scratches holds really strong. I like to scratch the contact surfaces with a metal point before gluing. Use sand paper in the contact points between the ruler, Legos and phone case. The case was glued to the frame and Legos with epoxy glue. The Lego blocks (red pieces in the image) were used to support the phone case. It can be corrected later in calculations. This is very difficult to do perfectly and a small axis error is acceptable. the viewfinder axis is parallel to the phone Z axis). Try as much as possible to keep the right angle between the eyepiece and the phone case, so that both the phone and the eyepiece point in the same direction ( I.E. The angle between the eyepiece and the phone must be fixed. The idea is to glue the pieces in a rigid and solid setup. Make it suit the viewfinder length more or less.īond the pieces together * Handle epoxy glue and putty with gloves.
Using a hand saw, cut off the point of the triangle ruler (you don't want that pointing to your eye).
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