Equinox Challenge

No, not that kind of Equinox, the Astronomical one.  We have a few days to plan our strategy.

September 23rd, the sun will rise due east and set due west regardless of where you are on earth  — shadows, likewise, will align due west at sunrise, and due east at sunset.

Find a clear view of the horizon on a quiet east-west street or road and photograph your bicycle as the sun rises or sets.   Its shadow will fall due west or east depending on which you choose, and the sun will be exactly in the middle of the road.

(This will be a one day challenge (obviously) — but it would be neat to do the same photo at the Winter and Summer Solstices.)

At the Winter Solstice, the sun will be well south of the road, and at the Summer Solstice, the sun will be well north of the road.   (Reverse that for the Southern Hemisphere.)

If you want to include a Chevy Equinox, thats fine too.  😉

The analemma shows the location of the direct ray of the sun and the amount of error of a sundial.

Here you can see the direct ray of the sun is approximately at 3 degrees N Latitude 9/14/18 and creeping south.


Very much enjoy all the entries you all have provided -- great to see the everyday cycling venues. Being in eastern Illinois, scenery certainly isn't our forte, but oh well, the roads are normally quiet. Look forward to more and more entries from all of you, I do have a few over on BL -- in Bill's Day Rides, and one journal.

7 response to "Equinox Challenge"

  1. By: Bill Stone Posted: September 13, 2018

    Great idea, Rich! I’ve updated the Challenge page and categories to include this one.

    PS: That must be your neighborhood in eastern Illinois in the photo. 😉

    • By: Rich-Illinois Posted: September 13, 2018


      Yup! The Down Town motel is just out of frame to the left, 😉

  2. By: Scooter Posted: September 14, 2018

    Oh sure, Rich. Specific day, time of day and orientation? I’ll never get all that down. I have enough trouble just remembering to include a bike in the picture.

    • By: Rich-Illinois Posted: September 14, 2018

      Heh — you too? I wander into the bathroom and then wonder why I did . . . . . . Oh yeah, NOW I remember.

    • By: Rich-Illinois Posted: September 14, 2018

      Thats my concern too, right now the weather couldnt be better — who knows what the 23rd might be.
      Addendum 9/16 — long range forecast calls for clouds and possible rain on the 23rd. 🙁

  3. By: Suzanne Posted: September 15, 2018

    Already scouting our neighborhood for where we might get the best east and west views!

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