Astronomy Learning and Research / Beginning Astronomy / Observational Astronomy

Analemma – Activity #1

Activity 1 So – here is the drawing I made from the dimensions of my apparatus, and the distances to both the equinoxes and the solstices.  The side marked “Gnomon” is the measurement from the ground to the height of the stick (gnomon).

I then measured the distance from the gnomon to the dots corresponding to the equinoxes and the solstices.

The drawing I used was full size. This drawing is just representative of my drawing. It’s not the actual drawing. It’s important for you to make the drawing full size in order to measure the angles for activity 1.

You will also need a protractor

For the first part of the activity – “measure the tilt of the earth’s axis using only your analemma and apparatus measurements.”

Take your protractor and measure angle a, then angle b. Then subtract b from a. This will be approximately 23 degrees which is the tilt of the earth’s axis.

Next – using your protractor measure the angle marked ‘latitude’. This is – you guessed it – your latitude!

Yea! One down  – three to go! Up next – Activity #2: with reference only to your analemma and measured dimensions of your observing apparatus, calculate the Sun’s path in the sky and produce a sketch or plot to depict that path.

Hmmmm – getting tougher!!


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