Category: Astrophotography

In addition to a supermassive black hole in its centre, which is 40 million times as massive as the Sun, this fascinating spiral galaxy contains an active nucleus – a compact region that emits luminosity not produced by the stars. It’s also a home of two recent supernovae, observed in 1981 and 2014.

M106 can be found in the Canes Venatici (Hunting Dogs) constellation, along with many other galaxies that all fit neatly into the field of view of my 478 mm-long telescope connected to a full-frame camera. NGC4217, seen from the edge in the top right part of the image, is a possible companion of M106. It’s located 60 million light-years away from us. 

This photo is a 4.5-hr, f/5.9 LRGBH exposure, collected over two nights in the beginning of May 2025. The light from M106 took 24 million years to reach my yard in Victoria, BC.

Taking a break from shooting galaxies far-far away: this colourful globular cluster is located within our galaxy, although in isolation – 38,800 light-years from the centre of the Milky Way and far above the galactic plane. M3 contains more than 500,000 stars, at least 274 of which are variable, which is more than any other known cluster. The brightness of variable stars fluctuates with time, making them useful for estimating their distances.

This image is a 4-hr LRGB exposure, taken at the end of April, 2025 in my yard in Victoria, BC. It took this light 34,000 years to travel here.

his is one of my favourite galaxies. It is one of the largest and brightest in the observable sky from my latitude, and it’s full of fascinating details. The pink glowing spots are the nebulae consisting of ionized hydrogen, where the new stars are formed. Clusters of these new hot stars are visible as the bright blue dots in the spiral arms.

The Pinwheel is nearly twice as large as our Milky Way galaxy – about 170,000 light-years across, and it contains trillion stars. Their light travelled for 21 million years to reach my camera in Victoria, BC.

This image is an integration of 5.5 hours of exposure, collected over two nights April 2025. 

This month, I was able to photograph nebulae in another galaxy! The bright red spots in the spiral arms of NGC 2403 are clouds of ionized hydrogen, where new stars are being born. The galaxy is also the place of the most recent observed death of a star – a supernova SN 2004dj was discovered in one of its arms by an amateur Japanese astronomer in 2004. A massive star exploded at the end of its life, shedding the outer layers of gas and sending them away from its collapsed core.

I think it’s incredible that we can observe these amazing deep-sky events from our backyards. This light travelled for 11 million years before reaching my camera in Victoria, BC. This photo required a processing approach that was new to me. It’s a 4 hours of total exposure, collected over two nights. The H-alpha light emission from the nebulae was captured through a separate narrowband filter and integrated into the LRGB (Luminance-Red-Green-Blue) image using the continuum subtraction technique.

Last week, I’ve collected about 5.25 hrs of total exposure of the famous Whirlpool galaxy. I photographed it almost exactly a year ago with a different camera, and it was the first galaxy image that I was quite pleased with. Well, the show itself didn’t change much in a year, although this is a galactic interaction in progress. The dwarf companion galaxy NGC 5195 has been flying past the Whirlpool for hundreds of millions of years, generating plumes of gas driven by the tidal forces between the two galaxies.

The M51 itself is about 400 million years old. We are seeing the stage of the intergalactic dance that actually happened quite a while ago because of how incredibly far these galaxies are. Their light travelled for 31 million years before reaching my yard in Victoria, BC.

I’ve had a chance to add a couple of exposure hours of M81 and it’s neighbour M82, the Cigar Galaxy (on the right in the wide-field image.) The pair was one of my first targets when I picked up astrophotography last year. 

M81 is 96,000 light-years in diameter, and the supermassive black hole in its centre has 15 times more mass than the black hole of our home Milky Way galaxy. Bode’s galaxy interacts with the nearby Cigar Galaxy, causing it to form new stars 10 times faster than the star-birth rate in the Milky Way galaxy.

The light in this photo is truly ancient – these photons travelled for 12 million years before reaching my camera. This is 5 hours of exposure collected at f/5.9 over two nights, almost exactly a year apart, from my yard in Victoria, BC.

One of the most recognizable nebulae, the dark head of a horse has its own catalogue number: B33. It’s a dense cloud of dust and cold hydrogen gas that blocks the light of the background stars and the red glow of ionized hydrogen. The large emission nebula in the background is IC 434 – an enormously active star-forming region. The bright young stars in it’s centre compress the gas with their stellar wind, creating new stars. The mass of the gas displaced by the ionization front of IC434 is about 10,000 Solar masses! I find it difficult to grasp the enormity of the number. This shouldn’t be surprising, of course, because there is nothing even remotely comparable to this truly astronomical mass that we encounter in daily life. For reference, one Solar mass is approximately 2*10^30 ( 2 nonillion) kg! 

The bright dots at the base of the Horsehead are the stars that have just been formed, and the bluish smudge to the bottom left is a small reflection nebula NGC 2023. The bright explosion-like emission nebula farther to the left is the Flame Nebula (NGC 2024), which has streaks of black dust blocking the background radiation.

This light travelled for 1,350 years before reaching my camera in Victoria, BC in January 2025. This is a 3.5-hr one-shot exposure at f/5.9 with a one-shot-colour (OSC) camera and a dual narrowband filter.

I wanted to photograph the Orion Nebula ever since becoming interested in astrophotography almost 30 years ago (in the pre-digital era!), and this is my first image, taken from my yard in Victoria, BC in January of 2025. 

One can easily find this beautiful nebula even with a naked eye just below the Orion’s Belt. M42 is 25 light-years across, and it is one of the closest star nurseries to our Solar system. Massive young stars whip up strong stellar winds that compress the surrounding gas, creating turbulence and shock waves, which in turn create more stars.

The Orion Nebula is exceptionally colourful. The red hues are due to the radiation of the ionized hydrogen, and the blue and violet colours are the reflected radiation of the gigantic O-type stars at the core. There is even a greenish hue, which is very rare in deep space, due to a low-probability electron transition in the ionized oxygen. It’s called the “forbidden transition,” because it is notoriously difficult to reproduce in a lab, which lacks the high vacuum of space.

This light travelled for 1,300 years before reaching my camera. This is a 3.5-hr exposure at f/5.9, using a full-frame one-shot colour (OSC) camera and a dual narrowband filter.

This emission nebula in the Cassiopeia constellation resembles its namesake character from the classic video game. It also resembles a heart if viewed from a different angle. It is rather dim and diffuse while observed visually, but is quite neat and full of details when photographed using multiple guided exposures. A small open star cluster (IC 1590) ionizes the gas of the Pacman, which is criss-crossed by lines of dark dust. It also contains several Bok globules, which are isolated dark nebulae that consist of dense clouds of dust and gas. These clouds are in the process of condensing and will form new stars in the future.

This future star nursery is located in the Perseus Arm of our Milky Way galaxy. I captured its light in early October of 2024, after it travelled for 9,500 years to my yard in Victoria, BC. This image is an integration of forty 5-minute RGB exposures, taken through a 478 mm-long, f/5.9 telescope. 

My current workflow for processing one-shot colour images of deep-space objects, particularly nebulae, heavily relies on the process of reconstruction a foraxx palette outlined in this video by Paulyman Astro (https://youtu.be/Gy42AeZ_XB4?si=lNb4B7a0jVKWi4I1).

The video is very detailed, and it has been exceptionally useful for me, but I found myself scrolling through it and pausing so much that I wanted to have a written summary of the steps that I could quickly refer to. Apologies in advance, if the following steps appear out-of-context – they are really short notes that would make sense to those who have used the Pixinsight software and worked with the foraxx palette.

Before this image processing is even started, I generate an integrated image using the following pre-processing sequence (see this guide by Adam Block for details: https://youtu.be/VKOTCuqD2Qs?si=EdbONwT8GO_DUAkR) :

First of all, all the individual exposures (light frames), which are typically 5-min long each, are calibrated with “flats”, “dark flats” and “darks” using the WeightedBatchPreprocessing script. 

Then, the resulted de-bayered images are aligned using the StarAlignment process.

Finally, the aligned images are integrated using the ImageIntergation process with Winthorised Sigma Clipping background rejection method. This produces the “integration.xisf” image, which is the basis for the nebula processing workflow itself:

1. Right-click on the identifier tab at the top-left of the image frame and set the new identifier to ‘osc’ (for ‘One-Shot Colour’).
2. Use Process>All processes>ScreenTransferFunction to preview a stretched image. I unlock the RGB channels before pressing the “nuke” button to avoid a high colour cast. This is not important though, because nothing is actually being done to the image – this is just a preview.
3. Use Process>All processes>DynamicCrop to crop the image.
4. Use AutomaticBackgroundExrtactor with Function degree (under Interpolation and Output) set to 1 and Target Image Correction to ‘Subtraction’. This works if there is simply some light pollution gradient in the image and little to no vignetting. Otherwise, use the DynamicBackgroundExtraction process.
5. Split the RGB channels using an icon in the toolbar.
6. Set the identifier of the Red channel to ‘ha’ for “Hydrogen alpha”.
7. Combine the Green and the Blue channel using the following Pixelmath expression: 0.5*B+0.5*G. Give the resulting image an identifier ‘oiii’. 
8. Use StarExterminator process to extract the stars. Check “Generate Star Image” and “Unscreen Stars” boxes. Drag the triangle from the process window onto the ha window and then onto the oiii window.
9. Use Generalized Hyperbolic Stretch (GHS) script or process to stretch the ‘ha’ and the ‘oiii’ (starless) images.
   • First stretch: Just right of the peak. Local stretch intensity ~10. Stretch factor ~3.
   • Second stretch: Secondary drop-off (log view). Local stretch intensity ~5.
10. Foraxx process: Create the false Green channel (‘ho’) using the Pixelmath expression: (ha*oiii)^~(ha*oiii). Press the square button.
11. Boost the brightness of the ‘ho’ image by doing the first-level stretch in GHS.
12. Create the colour image by using the Pixelmath expression (uncheck ‘Use a single RGB/K expression’, set Color space to ‘RGB color’):
    • R: ha
    • G: ho*ha+~ho*oiii
    • B: oiii
13. Apply CurvesTransformation. Start with saturation, proceed to individual channels.
14. Apply NoiseExterminator with default values or Denoise ~0.9, Detail ~0.55.
15. Stretch ‘ha_stars’ and ‘oiii_stars’ using HistogramTransformation. Use checkmark to track the histogram and use live preview to monitor the stretch amount. Drag middle slider to the left.
16. Apply the Foraxx process (step 10) to ‘ha_stars’ and ‘oiii_stars’.
17. Use CurvesTransformation to boost saturation of ‘foraxx_stars’.
18. Put the stars back using the Pixelmath expression: ~(~foraxx*~foraxx_stars).

And this is it! Here are some examples of my application of this process applied to various emission nebulae.