Steve & Debbie Russell's Telescope Clinic
A star wheel, sometimes called a planisphere, helps us identify constellations quickly and easily.
We avoid use of phone applications for three very good reasons:
(1) Your phone will destroy your night vision. Night vision increases when we are in the dark for fully 30 minutes, and once even a little night vision is gained, we don’t want to squander it.
(2) Your phone’s astronomy application does a very poor job of actually indicating which celestial object is which – objects
are small and the sky is very large, and the phone does not aim with enough precision to help.
(3) Relying on your phone application does not help you learn anything about the incredible night sky we have been given
but rather increases your dependence on the device. It is very gratifying to learn to identify constellations and asterisms in the night sky.
The star wheel linked below is fine for our location on Planet Earth, which is near 40° north latitude. This website has star wheels for 60° north, 64° north (really?) and one for the southern hemisphere. They can also be found in various languages.
If printed on card stock, it will last longer than plain paper. Plain paper can be glued to a file folder for another option. Humidity will make it curl and be less of a joy to use, and laminated ones can be found for nominal cost. We are fairly
familiar with the night sky, and we carry and use star wheels.
Instructions for assembly are printed on part that will be trimmed off, and instructions for use remain visible on the back of
the assembled star wheel for reference.
To use it, rotate the inner disk to line up the date with the time of day. The stars and constellations showing in the oval are what is above the horizon at that time and date. If Darkness Squandering Time (DST) is in effect, take that hour off the time set on the wheel. Note the horizons marked on the wheel holder and hold the star wheel with the horizon name of the direction you are facing upside-right. It is not without distortion to represent the spherical sky on a flat piece of paper.
