The Heart of a Nebula


Rob Nolan navigates the UK’s fickle weather, finally having to fall back on January’s rare clear skies to present another celestial gem


It feels like we just can’t catch a break at the moment – I think there have been only one or two clear-ish nights since the last issue of the BV was published! For astronomers in the UK, the collective frustration is building. Just when will we get some clear skies again?! This is always the challenge with amateur astronomy, especially here in the UK, and we must carry on with the hope of clear skies on the horizon!
Fortunately, I have a couple of targets to fall back on from January, and I decided to go for the heart of the nebula. The actual Heart Nebula to be exact!
IC 1805 is called The Heart Nebula due to its shape, but in this image I’ve deliberately focused on a column of ionised gas in the very centre.
This emission nebula is some 7,500 light years away from Earth, located in the Perseus Arm of our Galaxy, in the constellation Cassiopeia.
The Heart Nebula is made up of ionised hydrogen, oxygen and sulphur gases. It spans almost two degrees in our night sky, covering an area four times larger than the diameter of a full moon.
In this particular image I’ve created what is known as a HOO image.
This is where we use the oxygen channel twice during the processing to make the image, alongside the hydrogen data, and discard the sulphur channel narrowband data. This is what gives the image its rather menacing red and subtle green tones, compared with some of my other image finishes.
The image was captured using my dedicated mono astrophotography camera and a 1000mm Maksutov Newtonian reflector telescope, along with narrowband filters, in our own Dorset skies.

The night sky, March 2024 – Rob’s guide for your stargazing this month:

Oh I do hope we get some clear skies in March, because there is an absolutely stellar (pun intended) event to observe – it’s comet time!
Comet Pons-Brooks, which was first observed back in 1812, is set to pass close by to us on its recursive 71-year journey around our Sun.
It was last seen in 1954, so for many of us it’ll be the first time seeing it, and the first time it will be photographed by many astrophotographers. Throughout March, the comet will track from Andromeda to Aries. Named for its co-discoverers Jean-Louis Pons and William Brooks, the comet is expected to brighten from magnitude +7 to +5, and has experienced spectacular outburst during its past flybys, which could mean that, like Neowise back in 2020, it could easily become visible with the naked eye!
The comet will become ever more visible throughout March, so I really hope we get to witness this one. Grab your binoculars and scan low in the evening twilight to spot the comet.

In other news …
The comet really does trump most of the other celestial events scheduled for March, with our neighbouring planets putting on a pretty poor display at the moment – only Jupiter is holding the stage until Mercury decides to make an appearance much later on in the month.
However, when Mercury does decide to grace us with its presence in the skies, it’ll be its best appearance of this year, so that will be worth looking out for! On 24th March, Mercury will be at its greatest separation from the Sun; watch out and enjoy it in the twilight of dusk.
Other events of note this month include the spring equinox on 20th March, marking equal night and day length.
The Moon will become slightly dimmed by our Earth’s outer shadow, in what’s known as a penumbral eclipse between 4.53am and 9.32am on 25th March. However, the moon will be setting during this event for us in the UK, so unfortunately, you may not get to see much of it.
And then finally on March 31st at 1am, British Summer Time (BST) officially starts, so don’t forget to put your clocks forward that night!
Until next time, clear skies.


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