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The Heart Nebula

A glowing cloud of hydrogen the shape of a heart, lit from inside by a cluster of newborn stars.

Photographed by TPN Explorer from a garden in Leicester on the night of 23 September 2026, with a Dwarf 3 and a duo band filter. A two panel mosaic of 794 frames of 15 seconds, 3 hours 18 minutes in all. Tap the picture for a larger version.

Seeing it from the UK and Ireland

It sits in Cassiopeia, the W shape, which never sets from the UK and Ireland and climbs high on autumn and winter evenings, so there are months of the year to catch it. Your eyes will not show it, even from a dark site, and a telescope shows little more than a faint grey haze, because human eyes see no colour at that brightness. It is a camera object, and a wide one: it is too big for most telescopes, which is why this picture is two views joined together. A filter that passes hydrogen makes an enormous difference. This photograph was taken from a Leicester garden with the Moon 91 percent full, which is the kind of night a filter like that can still use.

Almost all of the red is hydrogen. A small group of very young, very hot stars sits inside the cloud, and their ultraviolet light strips the electrons off the hydrogen around them. When those electrons are captured again the gas gives out light at one particular red, and that one colour is the Heart.

The cluster doing the work is catalogued as Melotte 15, near the middle of the picture. Its brightest stars are only a few million years old and are many times heavier than the Sun. Their light and their winds are slowly carving out the inside of the cloud, which is why the middle of the Heart looks hollowed out and the edges look like walls.

The smaller, brighter knot above it to the right is the Fishhead Nebula, IC 1795. It is part of the same great complex of gas, and it is where the whole region is brightest.

The Heart is big. It spans about two and a half degrees of sky, five full moons side by side, and it lies around 7,500 light years away in the next spiral arm of our galaxy out from ours. It has a neighbour just off the left of this picture, the Soul Nebula, and the two together are often called the Heart and Soul.

The numbers

Also called
IC 1805, and Sharpless 190
Constellation
Cassiopeia, the W
Distance
About 7,500 light years
Size in the sky
About 2.5 degrees, five full moons across
What it is
A hydrogen cloud lit by young stars inside it
The cluster lighting it
Melotte 15, a few million years old
Above it to the right
The Fishhead Nebula, IC 1795
Visible to the eye
No, it is a photographic target
Best months from the UK and Ireland
September to March

To find out whether it is up tonight, and when it gets properly dark where you are, see Sky Tonight.