IC 1805 - The Heart Nebula in Narrowband

Mis à jour : 9 oct. 2020

Featured on "Sciences et Avenir"'s Instagram page - February 14, 2020

Shared by NASA's APOD on Instagram - August 24, 2020

IC 1805 is a huge nebula located 7,500 light-years away in the constellation Cassiopeia. It is full of Hydrogen Alpha and overall pretty faint at a magnitude of 18.3. Because of its size, the Heart Nebula is best photographed using a small telescope (480mm or smaller) so that you can fit the entire object in your frame.

Object Designation: IC1805

Also known as: The Heart Nebula

Constellation: Cassiopeia

Object Type: Emission Nebula

Distance: 7,500 light-years away

Magnitude: 18.3

Discovered in: 1787

With an even wider instrument (or a DSLR camera lens), you might also be able to include its neighbor, the Soul Nebula. IC 1848 is very similar to the Heart Nebula has it is also large and filled with Hydrogen Alpha gas. The two of them make for a fantastic wide-field image. If you would like to get both nebulae in the same frame but do not have a good camera lens or very wide telescope, you can also achieve this by doing a 4 or 8-panel mosaic.

Melotte 15 taken by Steve R Cooper

At the core of the Heart Nebula is a bright open cluster known as Melotte 15. The stars within the cluster are 1.5 million years old, which actually is pretty young in the life of stars.

This is a great target to photograph if you do not own a wide telescope. The beautiful pillar-like nebulosity looks like it is dancing with the stars that surround it.

We have not attempted to image this cluster by itself yet, but it is in our To-Do list for sure! We will update this post and add our image as soon as we photographed it.

The impressive picture visible on the left was taken by Steve R Cooper in narrowband.

Melotte 15 is not the only deep sky object within the Heart Nebula that you can concentrate on if you only own a medium size or large telescope. Another beautiful target available for your set up is IC 1795, or the Fish Head Nebula!

The Fish Head Nebula taken by Alan Pham

You can clearly see why this nebula got its name by looking at the picture on the right. The shape of the object and the division of colors show what appears to be a fish looking (or swimming?) towards the right. It even has a mouth!

Just like Melotte 15, we have not yet captured this object by itself but will update this post with our image when it is done!

Below is our photograph of the entire Heart Nebula. Can you spot both Melotte 15 and the Fish Head Nebula in there?

We spent 4 hours on this object at f/5. We are usually used to imaging at f/3.9, but since there is not a huge difference between these two numbers, we felt like 4 hours was enough. We're curious as to how much more gas would have shown if we did spend more time on it. Either way, we wouldn't have been able to anyway since we were freezing our butts off in the desert and desperately wanted to go home.

IC 1805 in Narrowband with the ASI 1600MM


Camera: ZWO ASI 1600mm Pro Mono

Telescope: Meade 70mm APO Astrograph

Mount: Atlas EQ-G motorized Mount

Guiding: ZWO ASI 290MM Mini

Acquisition: ZWO ASIAIR

Power: Pegasus Astro Pocket Powerbox

Processing: Pixinsight


Total Exposure Time: 4 hours

Exposure Time per frame: 3 minutes

Filters: Ha (2 hours) / SII (1 hour) / OIII (1 hour)

Gain: 139

Want to hang this photo in your home? Check out our prints!

Download our Raw data for the Heart Nebula HERE

How to find the Heart Nebula?

IC 1805 can be found just to the West of Cassiopeia’s “W” shape.

Because of the faint hydrogen alpha present in most of the nebula, the Heart is not really visible to the naked eye. You also should not expect to spot it with binoculars. Under very dark skies and with the correct filter, you might be able to see it with a good telescope. The cluster in the center of the nebula, on the other hand, can be observe quite easily with binoculars.

If you still cannot find it, try pointing your DSLR camera with a wide enough lens (we recommend 50mm) towards that area of the sky. A long exposure shot should reveal gas either from the Heart or the Soul Nebula located just next to it.

Cool Facts
  • About 5 times the size of the Moon

  • Most stars are formed in the Heart’s center

  • Sometimes also called the “Running Dog” nebula

Processing of IC 1805

Although the Heart Nebula might be a good bi-color target, we decided to image it with all three narrowband filters:

  1. Hydrogen Alpha

  2. Sulfur II

  3. Oxygen III

We combined these into the "Hubble Palette", meaning the HA channel is linked to Green, the Sulfur to Red and the Oxygen to Blue.

How much data can you get with each filter?

Before the channels can be combined into one color image, the individual frames for each filter need to be stacked.

Below you can see the result of 2 hours of exposure using the Ha filter (left), one hour using the Sii filter (center) and one hour using the Oiii filter (right).

We hope this can help you visualize how much data you can expect to get when you decide to image that target!

You can get our full PixInsight workflow PDF HERE.

Using StarNet to get a Starless Heart Nebula

In August 2020, StarNet became available natively on PixInsight (read our tutorial on how to get it working easily) and so I reprocessed our data of the Heart nebula and ran the module to remove all the stars!

This allowed me to be more aggressive in bringing out all of the faint nebulous gas in and around the object without affecting the stars. The end result is (in my opinion) absolutely gorgeous! I also saved a version with the stars added back onto the image, which you can see on our StarNet tutorial post.

Final Thoughts

It took us several years before deciding to image this target, but we are glad we waited! This is a perfect target for Narrowband imaging, and the image would have looked much less spectacular if we captured it with our unmodified DSLR camera.

What would we like to do next in this area of the sky? We'd love to get a closer look at the fish head nebula with a larger telescope, and image it individually. We'd also like to do the same for Melotte 15 in the center of the Heart. Also, we plan on photographing the nearby Soul Nebula soon, so keep an eye out on our gallery!

Have you captured the Heart Nebula? Attach your image in the comments and let us know what you used!

Want to hang this photo in your home? Check out our prints!

Make sure to follow us on Facebook, Instagram, and YouTube to stay up to date with our work!

Clear Skies,

Galactic Hunter



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#HeartNebula #IC1805 #narrowband #ZWO #ASI1600mm #ASIAIR

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