Night Sky Observation

March 2021

The first Night Sky Observation activity was carried out as an experiment and involved naked eye observation of the constellation of Taurus during the month of March. Observers were given a partial star map and asked to fill in the missing stars. The observation was made more interesting by the planet Mars passing through the region of the star map.

To see what should have been visible, visit the Time and Date website, and set the date to a day in March 2021.

Images Created by Participants

The following are a selection of the images created by the participants.

Materials Provided to Participants

Because this was a formal experiement as well as being an activity, participants were asked to complete a Consent Form and Questionnaire.



The Website Author

Alison McMillan, Prof in Aerospace Technology, Wrexham Glyndwr University and Chair IOP Wales. or

The Ashover Stones

The Hidden Objective of this Observation Experiment

The Ashover Stones shown here were discovered in Ashover, near Derby, England, about 20 years ago, and show prehistoric tooling marks.

Jonathan Powers (Emeritus Professor, University of Derby) proposed that these might depict start positions, and could have been used for agricultural purposes to determine the beginning of spring. He also proposed that the ring markings indicated the brightness of the star.

Further details are available in his monograph: Interpreting Prehistoric Rock Art - The case of the Ashover Stones by Jonathan Powers, which is available from the online shop of Derby Museum and Art Gallery.

The first Ashowever Stone
The second Ashover Stone

The Idea of Testing this Hypothesis

Collaboration between Jonathan Powers and Alison McMillan

The problem with Jonathan's hypothesis is that it is impossible to prove conclusively: the people who made the marks on these stones were unable to leave more detailed records as to their purpose.

Jonathan shared his book and ideas with me (Alison), and I considered the problem of testing the hypothesis over a couple of months. One of the arguments for rejecting the hypothesis was that the depictions were not acurate compared with a modern star chart.

Furthermore, in the Second Ashover Stone, which Jonathan believed to show Aldebaran and other stars in Taurus (bottom left) and The Pleiades (upper right), the scale of The Pleiades is about nine times too large compared with the distance between Aldebaran and the The Pleiades group.

The problem of scale begs two questions:

  1. Is there a natural tendancy to draw small but significant details oversize?
  2. Would it have been necessary to make a deliberate choice to depict those details oversize, given the quality of the tooling, and the size of the available rock?

I asked myself,

    How good are modern human beings at representing star positions by naked eye observation and free hand drawing?

At this time, it was near the end of February, and I knew that Taurus would only be easily visible in the night sky until around the end of March. When I looked up the precise times for Taurus I had a surprise: Mars would be passing through the constellation during exactly this time, and would provide an additional bright object for observation within the plotting challenge rectangle.

I discussed the idea with Jonathan, and the collaboration was born. I then, very rapidly produced instruction sheets, and my colleagues at Wrexham Glyndwr University were supremely helpful in arranging Welsh translation and Ethical Approval in time to launch the Night Sky Observation Experiment in early March. Ethical Approval was necessary, because it was important to conceal the true purpose of the activity.

Disappointingly, March 2021 was a cloudy month, and there were very few clear nights. Nevertheless, a few stouthearted participants did manage to record their images.

The Analysis

The star placement accuracy was assessed by digitising the images, and then measuring the distance between the centres of pairs of stars, and comparing this with the Time and Date website.

Not every participant included The Pleiades in their rectangle, but where they did, the relative distances between the individual stars of The Pleiades were compared with the depicted distance between Aldebaran and Alcyone (the brightest of The Pleiades).

The Results

In regard to placement accuracy, there was a huge variation in ability in modern humans, and this seemed to be completely independent of Astronomy knowledge or Artistic skill.

Every depiction of The Pleiades was drawn out of scale by between two and seven times.

The Conclusion

The star mapping accuracy and scale representation of modern humans is not incompatible with the hypothesis that the Ashover Stones represent Taurus and The Pleiades.