Michael Hotka's
Activity 3 - Align ATelescope During the Daytime Results

ou can “reverse engineer” the sundial process to find out at what clock time a shadow will point true north at your location on a particular day. Knowing this you can polar align an equatorial scope at local noon (which probably won’t be 12:00) using a shadow’s direction and a watch. This works particularly well for an observatory mounted scope. You need to include your longitude and equation of time corrections and possibly one for daylight savings time to calculate the exact time for that day. In use, point your scope north then horizontally level your R.A. and Dec axis. Mount a small thin vertical piece on top of your OTA near the cover so it can cast a shadow. When the clock time hits your local noon, the shadow points north. Make a mark and it can be used to align your scope again in the future.

At what time at your normal observing site does an object cast a shadow due north on your birthday? If you have an equatorial mount you may wish try this method of daytime alignment.

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