See the Wonder Star

The star known as Mira – the Wonderful One – has lived up to its name and brightened up to naked-eye visibility. 

The star Omicron Ceti, Mira, has a special place in the hearts of variable star observers, as it was one of the first stars to be recognised as being variable. It spends most of its time well below naked-eye visibility, but then over a matter of just a few weeks it brightens up and again joins the constellation pattern of Cetus.

Mira
Mira (circled), photographed on 25 November 2018 at 21:35 UT. The bright star at far left is Alpha Ceti in the Head of Cetus. Photo: Robin Scagell

It was this behaviour, first spotted in the 16th century, that earned it the name of Mira, meaning ‘Wonderful’. Until that time, stars were thought to be fixed and unchanging.

Mira has recently brightened and is now again visible to the naked eye, at magnitude 4, but the star could get slightly brighter as a normal maximum is around magnitude 3.6. As recently as six weeks ago it was around its minimum brightness of magnitude 9.

The peaks of 2007, 2010 and 2011 all reached around magnitude 2, so Mira then became virtually the brightest star in Cetus. In some years, maximum occurs when the star is too close to the Sun to be observed, but this maximum takes place when the star is easily visible in the evening sky.

Use the chart below to pick out Mira, which is best found by first using the stars of Aries to locate the brighter stars of the Head of Cetus, which is shown by a polygon just above Mira itself.

Mira chart
This chart shows the view looking south in late November at about 10 pm from the UK.

You can read more about Mira via this guide which also has a chart of comparison stars to help you make your own estimates of its brightness. Please send your estimates to our Variable Star Section Director, Matthew Barrett.