NGC 7293 - The Helix Nebula - DSLR vs ASI 1600MM

Updated: Mar 19

The Helix nebula, commonly known as the Eye of God, or even the Eye of Sauron, looks like a larger and brighter version of M57, the Ring nebula.

This planetary nebula is a very popular target for beginner amateur astrophotographers, not only because it has cool nicknames but also because it is very easy to capture.

We imaged this target with both our unmodified Canon 7D Mark II DSLR camera, and about 2 years later with our ZWO ASI 1600MM-Pro CMOS camera. We used the same telescope for both attempts and we will show you the two different results in this post.

We spent just under 3 hours of total time imaging it with the DSLR camera, and only half of that, one hour and 30 minutes with our CMOS camera. You will see that the ASI 1600MM camera's result is much better no matter the amount of time spent!

Below you can find our first attempt at the nebula taken with the DSLR camera, followed by our latest version of the Helix taken with the CMOS camera so that you can compare both images easily.

Imaging the Helix Nebula with a DSLR camera

October 21st, 2017

We went to our usual stargazing location in the desert from 6PM to 12AM. We contacted some of the Las Vegas Astronomical Society's members asking if they'd like to join for a night of imaging, and a few of them came with their telescope! It was fun and it felt nice not being all by ourselves in the middle of nowhere for once.

We decided to image the Helix Nebula knowing it would be too low in the horizon for the rest f the year very soon. Even though it was already really low, we spent about 2 hours and 45 minutes on it until it completely disappeared behind Laughlin's light pollution dome, visible in the distance.

We spent the rest of our time photographing IC 5146 (The Cocoon Nebula) and the star cluster M37. We only spent one hour on each and are pretty happy with Messier 37. The Cocoon though, definitely needs to be revisited.

The Helix Nebula with our Canon 7D Mark II DSLR Camera


Camera: Canon 7D Mark II

Telescope: Orion 8" Astrograph f/3.9

Mount: Atlas EQ-G motorized Mount

Coma: Baader MPCC Coma Corrector MkIII

Guiding: Starshoot Autoguider - 50mm Guide Scope

Processing: Pixinsight


Total Exposure Time: 2.7 hour

Exposure Time per frame: 3 minutes

54 lights - 15 Darks - 15 Bias

ISO: 800

Imaging the Helix Nebula with a cooled Astrophotography camera

October 31st, 2019

Two years later, we went back to that same stargazing location in the desert with the same telescope and mount but a different camera!

NGC 7293 was even lower in the horizon than the last time, so we only had the time to do an hour and 30 minutes of total exposure. This is also the first time we decided to do BiColor imaging, using only our Hydrogen Alpha and Oxygen III filters. The final result turned out beautiful anyway as you can see below. We find it really crazy that the stars in the DSLR image are much more bloated than the ones in this version, knowing we followed the exact same processing workflow for both. This might be because we were imaging in RGB rather than Narrowband.

The Helix Nebula with our ASI 1600MM Camera


Camera: ZWO ASI 1600mm Pro Mono

Telescope: Orion 8" Astrograph f/3.9

Mount: Atlas EQ-G motorized Mount

Coma: Baader MPCC Coma Corrector MkIII

Guiding: ZWO ASI 290MM Mini

Acquisition: ZWO ASIAIR

Power: Pegasus Astro Pocket Powerbox

Processing: Pixinsight


Total Exposure Time: 1 hour and 30 minutes

Exposure Time per frame: 3 minutes

Filters: Ha (45 minutes) / OIII (45 minutes)

Gain: 75


Spending about two hours on this target will give you the beautiful, colorful nebula as seen on the image on the left.

Note that ours is affected by a little bit of light pollution from a nearby city, so you might be able to get a cleaner image than this one with the same exposure time!

Cooled monochrome:

Using a monochrome astrophotography camera, the narrowband filters really help in revealing the fain outer gas as you can see on our image to your right.

We wish we could have spent more time on it to gather more data but this is all we could get! It is still beautiful though and we can always add more to it next year. We always make sure to keep our raw files in a folder in case we want to stack more over time!


Adding several more hours will allow you to capture the fainter, outer gases being expelled. The picture on the left is from the Hubble Space Telescope.

Although our DSLR version doesn't do it justice, know that it is really easy to photograph this target and have it look very close to Hubble's version even with a cheap camera.

Locating the Helix Nebula

The Helix nebula can be found in the Aquarius constellation, in an area devoid of bright stars.

Even though the Helix is the brightest planetary nebula in the night sky, it is not that easy to observe.

Because of its size, the nebula has a low surface brightness, making it difficult to spot through a large telescope. The key is to use binoculars or a low power telescope so that the light from the Helix can be concentrated in one obvious spot in the wide visible sky.

NGC 7293 can also be seen with the unaided eye, as long as your vision is excellent and no light pollution is present from your observing site.

Keep in mind that from any place in the United States, the Eye of God does not rise very high in the sky, and disappears after a few weeks. Make sure to capture it before it is gone or you will have no choice but to wait an entire year to meet it again.

Cool Facts
  • First planetary nebula discovered to have cometary knots (about 20,000)

  • Expands at a rate of 40km/s

  • About half the size of the full moon

Single Shot & Processing of the Helix Nebula - DSLR Camera

We had the chance to take a few shots of the Helix from our usual imaging spot (Bortle 3.5) but also from a Bortle 1 zone near Tonopah, Nevada! As you can see below, the difference is very impressive! Sadly, our laptop literally broke during our Tonopah night and we were unable to image the Helix Nebula from there, so all the stacked image are from the Bortle 3.5 zone.

When it comes to the processing of NGC 7293, we had a little bit of trouble with the noise reduction because although we imaged from a pretty good Bortle zone, the Helix was low in the horizon and we had to shoot through Laughlin's (city not far from Las Vegas) light pollution dome.

We would really like to add more data to this next year, and make sure it is higher in the sky when imaging.

Single Shot & Processing of the Helix Nebula - Cooled Camera

Processing the nebula was a true challenge for us this time because it was our first attempt at Bi-Color imaging! We had no idea how to combine two filters into three channels and we spent a long morning trying to figure it out. Thankfully, the internet is a wonderful place full of great tutorials and we were able to successfully stack our files using PixelMath on PixInsight.

Below you can see the 45-minute stacked images for both narrowband filter used: Ha and OIII. As you can see, they both look very different! The Hydrogen Alpha filter reveals all the outer gases, while the OIII filter only shows what's within the nebula. It's pretty fascinating.

Final Thoughts

The Helix nebula is a very popular target among amateur astrophotographers. We recommend you give this one a try before attempting M57, the Ring Nebula, as this target will be a larger and easier version.

Make sure to capture it as soon as it gets dark and when it is as high as possible in the sky, because NGC 7293 does not rise much in most locations!

Enjoying posts like this one where we compare two images taken several years apart with different equipment? Click on an image below and check them out!

Clear Skies,

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