How we shot the Christmas Tree Cluster from 2,500 light-years away

Mar 9, 2023

Antoine & Dalia Grelin

Udi Tirosh is an entrepreneur, photography inventor, journalist, educator, and writer based in Israel. With over 25 years of experience in the photo-video industry, Udi has built and sold several photography-related brands. Udi has a double degree in mass media communications and computer science.

How we shot the Christmas Tree Cluster from 2,500 light-years away

Mar 9, 2023

Antoine & Dalia Grelin

Udi Tirosh is an entrepreneur, photography inventor, journalist, educator, and writer based in Israel. With over 25 years of experience in the photo-video industry, Udi has built and sold several photography-related brands. Udi has a double degree in mass media communications and computer science.

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Most amateur Astrophotography images have a total integration time of between one and four hours. This is the total time that the shutter is open (even if with several images stacked). We decided to spend 81 hours on this picture which is our personal record.

We shot NGC 2264, a spectacular piece of space tat is mostly occupied by the Cone Nebula and the Christmas Tree Cluster and a few others). Going from a four-hour “exposure” to an 81 hours exposure is not a giant leap, but a series of steps. This is how we got here.

The clipped photo above (and the full photo below) is NGC 2264, an area designation that includes a few astronomical objects:

  • The Christmas Tree cluster
  • The Cone Nebula
  • The Fox Fur Nebula
  • The Stellar Snowflake Cluster

All in all, it resembles a space Christmas tree made up of Hydrogen Alpha, Oxygen III, and Sulfur II.

It is a large and colorful nebula 2,500 light-years away in the constellation Monoceros, not far from the famous Orion Nebula.

Monoceros Map
A map of Monoceros – where we shot the Christmas Tree Cluster

We actually spent a total of 114 hours taking pictures of NGC 2264 in the past three months, because we wanted to show the object both in true color and in narrowband (Hubble style). In astrophotography, the total integration time is very important because the signal-to-noise ratio gets better the more time you spend on a target, up to a point. The goal of spending so much time on this specific target was to reveal as much faint gas as possible, and completely eliminate all visible noise from the data to get the cleanest possible image.

Project 1 – 33 hours of integration time

Askar and QHY600 rig
Askar and QHY600 – the rig in our backyard

The first project was true color, and was done from our backyard. We spent a total of 33 hours with our beginner telescope and full-frame camera and were able to get the picture you see below. It shows the true color of the hydrogen alpha gas (red), which overwhelms the entire nebula.

It is a beautiful image, but we wanted more. We wanted to start again from scratch, but this time using a monochrome camera and a full set of narrowband filters.

NGC 2264 - Xmas Tree duoband
NGC 2264 – Xmas Tree duo band – 33 hours of “exposure”

Project 2 – 81 hours of integration time

This is our new integration time record, beating our 61-hour-long image of the Seagull & Thor’s Helmet nebula last year.

This time used a bigger telescope which we installed permanently in the middle of the desert in Utah at a place called Utah Desert Remote Observatories. We are able to connect to our telescope remotely from anywhere in the world and take pictures under a very dark sky. Using this telescope and six different filters, we spent several weeks slewing to the Christmas Tree every single clear night and gathering as much data on it as possible. Our telescope can be seen below in the orange square.

Inside of observatory
That’s our baby, in the orange square

In case you are wondering, here are the setup, and the technical details

  • Telescope: Stellarvue SVX130
  • Mount: 10Micron GM1000HPS
  • Camera: QHY600M
  • Filters: S, H, O, R, G, B
  • Exposure time for S, H, O: 20 minutes per frame
  • Exposure time for R, G, B: 60 seconds per frame
  • Total: 81 hours

Below you can see what the data looked like through each narrowband filter (HA, SII and OIII). The three other filters (R, G, B) were used for the stars.

ngc 2264 with three different filters
This is what the capture looks like via three different filters

Post Processing

Processing was very time-consuming and tricky, but also so much fun.

The total number of individual files we had to calibrate and combine was 533. This includes all light and calibration frames. It took the computer almost a full night to finish the calibration and stacking.

We were able to get a color image of the object once the three monochrome channels were combined, and it looked incredible. Having so much data on this object made all the colors pop and mix naturally before even starting to process the image, and the noise was basically non-existent. We then had to be careful while processing not to clip any highlights, or bring out the details too much to keep any noise from showing.

pi dashboard
post-processing – pi dashboard

Overall, this image turned out incredible, mostly due to the natural mix of colors, the crisp details, and the fact that there is no visible noise at all. It is 60MP and, when viewed in full resolution, looks very clean, even in extreme zooms.

Xmas Tree Narrowband
Xmas Tree Narrowband – with all the different filters combined

About the Author

We are Antoine and Dalia Grelin. For the last ten years, we’ve been honing our skills as amateur astrophotographers. Our goal is to motivate people to jump into this wonderful hobby of astrophotography and help others to capture their first images of the night sky.

We do this through videos on our Galactic Hunter YouTube channel, hundreds of written tutorials on our astrophotography website, and through books about astrophotography. Half of our images are taken from the desert, far away from all the light pollution of the city, and the other half from our backyard in Las Vegas, NV using specialized filters

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One response to “How we shot the Christmas Tree Cluster from 2,500 light-years away”

  1. Dunja0712 Avatar
    Dunja0712

    Wow. Both versions are insanely beautiful! Well done!