South Celestial Pole

Star Trails

Constellation: Octans
Image exposure:
25 minutes
Image field of view:
approx 15° x 15°
Image date:

The stars in this zoomed image are almost entirely within the single constellation of Octans, generally regarded by amateur astronomers as a barren region with very few objects worth looking at.

You may notice two brief satellite trails, probably from a single Iridium satellite in a polar orbit.

During this 25 minute exposure of the South Celestial Pole, the rotation of the Earth moved the stars about 6.2° in a clockwise direction around the Pole, which is at the centre of this image, 34° above my southern horizon.

They’ll be back again tomorrow, providing irrefutable evidence that the Earth is a sphere, spinning at the rate of 23h 56m 4.1s every 24 hours.

Planet Earth (Wikimedia Commons)

Meanwhile, here in Eastern Australia ☹ :


Cosmic Focus Observatory

34° South

Above us only sky….


Imaging camera:Canon EOS 60D
Lens:Tamron 70-200mm lens @70mm
Exposure:99 x 15 seconds, f/6.3, ISO 400

Images © Roger Powell


  1. Nice . . . although the FEI would say a rotating disk would show the same thing if looking along the axis of rotation.

    The satellites might offer more proof of sphericity than the star trails . . . were the Earth flat, they would just keep on going and never be seen again, and our phones would stop working.

    Liked by 1 person

  2. Sorry for your dismal weather down there. I see three trails, all generally, (or exactly?) in the same angle, which may indicate some common association. And yeah, it does look odd to me, without Polaris! M 🙂

    Liked by 1 person

Leave a comment or ask a question . . . .

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s