A guide to the Moon’s Copernicus Crater

Facts about Copernicus Crater, one of the most prominent craters on the Moon.

Crater Copernicus + Montes-Carpatus by Marc Delaney, Barry, Wales, UK. Equipment: Meade-LS-ACF-6

One of the most important and striking craters on the Moon, Copernicus is found in the Oceanus Procellarum, slightly northwest of centre.

Advertisement

It is easy to identify whenever it is sunlit, and it is at the heart of one of the two main ray-centres.

Crater Tycho, in the southern uplands, is the other. Under high lighting, the Tycho and Copernicus rays are so dominant that they make other features difficult to locate.

Moon showing Copernicus Crater by David Burr, Wimborne, Dorset, UK. Equipment: Celestron C8, Canon 550D.
Moon showing Copernicus Crater by David Burr, Wimborne, Dorset, UK. Equipment: Celestron C8, Canon 550D.

Facts about Copernicus Crater

  • Size: 90km
  • Age: Less than a billion years
  • Location: Latitude 9.7ºN, longitude 20ºW
  • Recommended observing equipment: 4-inch telescope

Copernicus Crater is named after the great Polish scholar who showed that Earth orbits the Sun, rather than being the centre of the Universe – but there is a story here, not without its amusing side.

The main craters were named in 1651 by astronomer Giovanni Riccioli, who drew the first really useful telescopic map of the Moon.

Not unnaturally he named prominent features after himself and his pupil Grimaldi, but he was no supporter of Copernicus, and continued to believe the old Ptolemaic geocentric theory of a stationary, motionless Earth.

To show his contempt, he “flung Copernicus into the Ocean of Storms”. His plan misfired; the crater he chose is magnificent, and is often referred to as ‘the Monarch of the Moon’.

Copernicus Crater by Ian Peck, Londonderry, N. Ireland. Equipment: SkyWatcher 200p, Logitech C270HD webcam.
Copernicus Crater by Ian Peck, Londonderry, N. Ireland. Equipment: SkyWatcher 200p, Logitech C270HD webcam.

Because Copernicus is not far from the centre of the lunar disc it is not appreciably foreshortened, and is on view for a good part of every lunation. It is 90km in diameter with high, beautifully terraced walls.

There is no single central mountain, but there are several peaks and groups of hills near the middle of the floor, which is otherwise fairly level and has not been flooded with lava.

It is fascinating to watch the progress of sunrise or sunset over the crater and the surrounding area; the whole scene changes dramatically over a short period of time.

The rays extend for at least 805km, and overlap rays from other craters, notably Kepler, so they must be younger.

Copernicus and Kepler by Mike Jennings, Leeds, UK. Equipment: Celestron C8 SCT, QHY5 CCD.
Copernicus and Kepler by Mike Jennings, Leeds, UK. Equipment: Celestron C8 SCT, QHY5 CCD.

Copernicus post-dates the Late Heavy Bombardment, and may well be less than a billion years old.

The rays differ from those of Tycho, because its rays are long, linear and regularly arranged, while those from Copernicus are less regular and give the impression of being tangential to the crater.

There are small secondary craters, and the area is hilly.

Copernicus is bright because, on the lunar timescale, it is so young. It has not been darkened by the effects of the solar wind or micrometeorite bombardment.

The rays are surface deposits, and do not show up until the Sun is well above their horizon.

Well to the northeast of Copernicus, not far from the end of the Apennines, lies the 58km diameter crater Eratosthenes, which is very like a slightly smaller edition of Copernicus, apart from the fact that it has no comparable ray system.

Craters Copernicus & Eratosthenes by Ralph Smyth, Lisburn, Co. Antrim. Equipment: Celestron C8 SCT, HEQ5PRO mount, ASI 120MM camera.
Craters Copernicus & Eratosthenes by Ralph Smyth, Lisburn, Co. Antrim. Equipment: Celestron C8 SCT, HEQ5PRO mount, ASI 120MM camera.

Southwest of Eratosthenes we find crater Stadius, which must have once been a grand formation, but has been so overwhelmed by lava that it has been reduced to the status of a ghost.

The walls are traceable under suitable lighting conditions, but nowhere rise to more than a few tens of feet.

In 1966, when mapping the Moon from spacecraft had only just begun, an oblique view of Copernicus was shown in an image from NASA’s Lunar Orbiter 2.

It was widely acclaimed, and became known as ‘the Picture of the Century’. It is still well worth looking at, and it is easy to see why this crater deserves its nickname – the Monarch of the Moon.

Below is a selection of images of Crater Copernicus captured by lunar astrophotographers and BBC Sky at Night Magazine readers.

For more info on how to make the most of our Moon, read our guide on how to observe the Moon or our pick of the best features to observe on the Moon.

Or try our tutorials on how to photograph the Moon and how to draw the Moon.

Advertisement

And don’t forget to send us your images or share them with us via Facebook, Twitter and Instagram.

Crater Copernicus captured with a Nikon CoolPix 4500 camera attached to a 125mm Schmidt-Cassegrain on an equatorial mount. Credit: Ade Ashford
Crater Copernicus captured with a Nikon CoolPix 4500 camera attached to a 125mm Schmidt-Cassegrain on an equatorial mount. Credit: Ade Ashford
Copernicus by Andy Wakefield, Portsmouth, UK. Equipment: 7
Copernicus by Andy Wakefield, Portsmouth, UK. Equipment: 7″ Starfire Refractor, Orion Starshoot Colour Imager.
Copernicus at Sunrise by John Hall, Belfast. Equipment: 130mm F9 refractor, 4x barlow, SPC 900 Philips webcam
Copernicus at Sunrise by John Hall, Belfast. Equipment: 130mm F9 refractor, 4x barlow, SPC 900 Philips webcam
Kepler and Copernicus by Mike Jennings, W. Yorkshire, UK. Equipment: CCelestron C8 SCT, QHY5 CCD.
Kepler and Copernicus by Mike Jennings, W. Yorkshire, UK. Equipment: CCelestron C8 SCT, QHY5 CCD.
2/3 Phase of the Moon showing Copernicus Crater 1st May 2012 by David Burr, Wimborne, Dorset, UK Equipment: Canon Eos 550d, Williams Optic 120 Refractor, Skywatcher Eq6 Mount
2/3 Phase of the Moon showing Copernicus Crater 1st May 2012 by David Burr, Wimborne, Dorset, UK Equipment: Canon Eos 550d, Williams Optic 120 Refractor, Skywatcher Eq6 Mount
Kepler and Copernicus by Brian S Parker, Wales, UK. Equipment: 200mm Skywatcher, Qhy5t, Neq6 mount.
Kepler and Copernicus by Brian S Parker, Wales, UK. Equipment: 200mm Skywatcher, Qhy5t, Neq6 mount.
Copernicus by Fred Connell, Gloucestershire, UK. Equipment: Skymax 127, Orion Starshoot Imager IV video camera.
Copernicus by Fred Connell, Gloucestershire, UK. Equipment: Skymax 127, Orion Starshoot Imager IV video camera.
Crater Copernicus by George Zealey, Effingham, Surrey, UK. Equipment: EQ5 PRO Mount, Celestron Nexstar 4
Crater Copernicus by George Zealey, Effingham, Surrey, UK. Equipment: EQ5 PRO Mount, Celestron Nexstar 4″, Logitech Quickcam Webcam.
Copernicus Region of the Moon by Peter J Williamson FRAS, Whittington, Shropshire, UK. Equipment: Celestron 9.25
Copernicus Region of the Moon by Peter J Williamson FRAS, Whittington, Shropshire, UK. Equipment: Celestron 9.25″ SCT, Vixen Sphinx Mount, ZWOASI120MM CCD.
Copernicus Crater by Peter Louer, Tenerife. Equipment: Canon EOS 700D at Prime focus, Meade 105ETX.
Copernicus Crater by Peter Louer, Tenerife. Equipment: Canon EOS 700D at Prime focus, Meade 105ETX.
Copernicus by John Brady, Lancashire, UK. Equipment: Skywatcher 200p, DMK41 mono CCD, 3X barlow
Copernicus by John Brady, Lancashire, UK. Equipment: Skywatcher 200p, DMK41 mono CCD, 3X barlow
Kepler and Crater Rays by John Brady, Lancashire, UK. Equipment: Skywatcher 200p, DMK41 mono CCD
Kepler and Crater Rays by John Brady, Lancashire, UK. Equipment: Skywatcher 200p, DMK41 mono CCD
Copernicus by John Brady, Lancashire, UK. Equipment: Skywatcher 200p, DMK41 mono CCD, 3X barlow
Copernicus by John Brady, Lancashire, UK. Equipment: Skywatcher 200p, DMK41 mono CCD, 3X barlow
Copernicus, Eratosthenes and Apennine Mountain Range by Alastair Woodward, Derby, UK. Equipment: Skywatcher 130PDS, x5 Barlow, HEQ5, QHY5L-II.
Copernicus, Eratosthenes and Apennine Mountain Range by Alastair Woodward, Derby, UK. Equipment: Skywatcher 130PDS, x5 Barlow, HEQ5, QHY5L-II.
Lunar image - Keplar by David Hughes, New Forest, UK. Equipment: Orion Europa 200, EQ5 Mount, Celestron NexImage Solar System Imager.
Lunar image – Keplar by David Hughes, New Forest, UK. Equipment: Orion Europa 200, EQ5 Mount, Celestron NexImage Solar System Imager.
Crater Copernicus + Montes-Carpatus by Marc Delaney, Barry, Wales, UK. Equipment: Meade-LS-ACF-6
Crater Copernicus + Montes-Carpatus by Marc Delaney, Barry, Wales, UK. Equipment: Meade-LS-ACF-6″, ZWO-178MC
Copernicus and Eratosthenes by Avani Soares, Parsec Observatory, Canoas, Brazil. Equipment: C14 Edge, ASI 290, IR 685
Copernicus and Eratosthenes by Avani Soares, Parsec Observatory, Canoas, Brazil. Equipment: C14 Edge, ASI 290, IR 685
Copernicus, Eratosthenes and Apennine Mountains by Alex Houston, Tullibody, Clackmannanshire, UK. Equipment: ZWO ASI120MM-s, SkyWatcher EVOSTAR 100ED2, 3x Barlow.
Copernicus, Eratosthenes and Apennine Mountains by Alex Houston, Tullibody, Clackmannanshire, UK. Equipment: ZWO ASI120MM-s, SkyWatcher EVOSTAR 100ED2, 3x Barlow.
Kepler Crater by Fernando Oliveira De Menezes, Sao Paulo, Brazil. Equipment: C11 Edge HD, Asi 174mm, Moon Baader Filter
Kepler Crater by Fernando Oliveira De Menezes, Sao Paulo, Brazil. Equipment: C11 Edge HD, Asi 174mm, Moon Baader Filter