The look of the polar scope

The look of the polar scope

So the polar scope in my mount is a rather basic one. It does have some constellations but they are more like drawings. The only point having been marked is a small circle where Polaris should go. And this is not enough for astrophotography – especially if the scope is not guided.

Of course one needs a few things for a good alignment, which basically boil down to knowing the geographical position of the scope and the (sidereal) time. These are things for a chart or a computer to know, not for a human, so I decided I wanted an elegant solution.

Therefore I came up with this ( script for smartphones. The script takes the user’s geo-position plus the date and time and shows the expected view plus some tech info. After adjusting the mount to show the expected view the only thing remaining is to get Polaris into the circle. I saved a shortcut on my phone’s desktop so when I tap on it, it shows me how to set up my scope.

The script has a few tweaks like the position of Polaris is J2015 instead of J2000, but I found it’s accuracy could be improved. However, it should be good enough for the next few years, and it’s made my hobby a bit easier. Needless to say, the script works for any polar scope (I have this rather basic one pictured above) in any mount (I have an EQ3) until the circle around the pole is the same and the image is inverted the same way.

If you don’t like using my site or are paranoid about it then feel free to copy the source and host it yourself – see the stuff in the grey rectangle.