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The Owl Cluster (NGC 457)

ET or Owl? I imaged the Owl Cluster in Cassiopeia

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ET or Owl? I imaged the Owl Cluster in Cassiopeia

Less than 1 minute Minutes

On October 27, 2025 I completed an imaging session of one of my favorite open clusters, NGC 457, also known as the Caldwell 13, Owl Cluster or E.T. Cluster.

Located in the constellation Cassiopeia and 7,900 light-years away, the Owl Cluster has many bright, colorful stars that form a pattern that resembles an owl or a certain friendly alien!

Its two bright “eyes” (φ Cassiopeiae & HD 7902) and wide “wings” give it a unique, photogenic look.
With a visual magnitude of 6.4, it’s an easy target for a binoculars and astro-imagers.

Acquisition details:

  • Telescope: Explore Scientific ED80CF

  • Camera: ZWO ASI533MC Pro (–10 °C)

  • Filter: Optolong L-Pro

  • Mount: Juwei17

  • Guiding: PHD2

  • Control: NINA on Mele fanless MiniPC

  • Frames: 2 hours 42 minutes total integration (81 x 120 secs. subs)

  • Processing: PixInsight & GIMP

The Owl Cluster (NGC 457)

One feature I consistently use and enjoy is the Touch-N-Stars plugin in NINA. I especially love its 3-point polar alignment. With Touch-N-Stars, I can run and monitor my entire imaging session right from my smartphone, so I don’t need to connect to my MiniPC through remote desktop, as long as I have preloaded an advanced sequence in NINA.

And yes, I’ve just added a custom horizon in NINA, so even more automation is on the way… Stay tuned!

Touch-N-Stars NINA plugin, Three Point Polar Alignment
The Pleiades (M45) - 2025-10-25

I Imaged the Pleiades from My Backyard: More Automation, Better Results

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I Imaged the Pleiades from My Backyard: More Automation, Better Results

Less than 1 minute Minutes

What a night! I spent it imaging the Pleiades (M45) from my backyard in Richmond Hill (Bortle 7-8), as I continue implementing incremental optimizations to my NINA imaging setup. The sky transparency was above average, and at times even excellent, allowing this iconic cluster and its delicate blue reflection nebulae to shine beautifully despite the city glow.

M45 – known in Greek mythology as the Pleiades or the Seven Sisters, and in Japanese as Subaru – is a young open cluster about 440 light-years away in Taurus. It contains hot blue stars that illuminate nearby interstellar dust, creating the famous bluish reflection nebula that surrounds the cluster. The glow is not coming from the stars themselves, but from starlight scattered by fine dust grains drifting through space.

My biggest dilemma for the night was exposure time:
More 120-second subs to avoid oversaturating the brightest stars, or fewer 180-second subs to capture more of the faint blue dust?
I chose 120-second exposures, collecting 3 hours of total integration, and I am overall very happy with how it turned out.

Guiding was a dream – as the PHD2 chart screenshot shows, the guiding lines stayed almost perfectly flat throughout the session.

I also added GroundStation notifications via Pushover to my Advanced Sequence in NINA, so I now get real-time alerts directly on my smartphone for every key step (and for any errors, if they occur): session start and end, mount homing, flat capture, camera warm-up, full equipment disconnect, and even PC shutdown, all handled automatically through the sequence.

I’m really happy with the level of control and reliability I’ve reached. One of my next planned improvements is to create a custom horizon profile in NINA for more precise scheduling and optimized imaging time.

The reflection nebulosity around the Pleiades is clearly visible after just three hours of integration, but I plan to add more hours on the next clear nights to bring out even finer dust details.

The Pleiades (M45) - 2025-10-25

Acquisition Details

  • Target: The Pleiades (M45)

  • Location: Backyard, Richmond Hill (Bortle 7–8)

  • Telescope: Explore Scientific ED80CF

  • Camera: ZWO ASI533MC Pro (–10 °C)

  • Filter: Optolong L-Pro

  • Mount: Juwei17

  • Guiding: PHD2

  • Control: NINA + GroundStation plugin (automation & Pushover notifications)

  • Frames: 3 h total (120 seconds subs)

  • Processing: PixInsight & GIMP

This screenshot shows PHD2 guiding during October 25, 2025 session. Polar alignment error was approximately 2 arcminutes and guiding was very smooth for the entire imaging session.
This screenshot shows PHD2 guiding during October 25, 2025 session. Polar alignment error was approximately 2 arcminutes and guiding was very smooth for the entire imaging session.
This screenshot shows the Pushover notifications I configured in my NINA advanced sequencer (through the GroundStation plugin).
This screenshot shows the Pushover notifications I configured in my NINA advanced sequencer (through the GroundStation plugin).
The Double Cluster in Perseus

I Captured the Perseus Double Cluster in Stunning Detail

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I captured the Perseus Double Cluster in stunning detail

Less than 1 minute Minutes

This image of the Double Cluster in Perseus (NGC 869 and NGC 884) was captured under perfectly clear skies, with 4 hours of total integration using the Optolong L-Pro filter.

Acquisition details:

  • Telescope: Explore Scientific ED80CF

  • Camera: ZWO ASI533MC Pro (–10 °C)

  • Filter: Optolong L-Pro

  • Mount: Juwei17

  • Guiding: PHD2

  • Control: NINA on Mele fanless MiniPC

  • Frames: ~4h total integration

  • Processing: PixInsight & GIMP

Polar alignment went incredibly smoothly, thanks to the 3D-printed tripod leg markers I made for my setup. With them, alignment now takes less than five minutes, and guiding stayed perfectly stable all night.

As a bonus, I tried to do some science with the HR Diagram plugin by Cosmic Photons, which generates a true Hertzsprung–Russell diagram from color-calibrated cluster images.

The repository for the PixInsight script can be found here.

Adam Block made a great YouTube video that explains how to use this script.

It’s fascinating to see how well the stars in this field trace the main sequence,  just like in a textbook!

The Double Cluster in Perseus

The Hertzsprung-Russell diagram of the Double Cluster in Perseus plots absolute magnitude versus color index. Stars occupy a clear main sequence, with the turn-off around 0.5-1.0, indicating the most massive members are leaving the main sequence and becoming blue giants or red supergiants.

The mix of bright blue stars and red supergiants confirms that the clusters are only 10-15 million years old, and the diagram shows how stars of the same age can follow very different paths. (becoming blue giants or red supergiants depending on their mass), making it a natural laboratory for stellar evolution.

Double Clusters in Perseus - HR Diagram
M45 (2024-10-24)

I imaged the Pleiades with a Rokinon 135mm Lens

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I imaged the Pleiades with a Rokinon 135mm Lens

2 Minutes

Another perfect night for astrophotography showed up, with skies so clear it was impossible to resist the call of the cosmos. Equipped with my Rokinon 135mm f/2 lens, an OSC camera, a light pollution filter, the ASIAIR Plus and my trusty Celestron AVX mount I let my rigs run for few hours to capture the beautiful Pleiades (M45), in Taurus.

The Pleiades are a prominent open star cluster located in the constellation Taurus, with an approximate distance of 444 light-years and an apparent magnitude of 1.6, making them one of the brightest clusters visible to the naked eye.

The Rokinon 135mm lens, known for its excellent sharpness, low coma aberration and fast f/2 aperture, is consistently demonstrating to be an ideal choice for wide-field astrophotography.

To reduce the light pollution in my area (I live under a Bortle 7-8 sky), I used the Optolong L-Pro filter. This specialized filter effectively suppressed artificial light while preserving the natural colors of stars and nebulae.

I spent the first part of the night imaging another target, while waiting for M45 to be hight enough in the sky. I planned to capture a total of 1 hour subs. As usual, for post-processing I used PixInsight and GIMP.

Setup

Date: 2024-10-24
Location: My backyard in Richmond Hill, ON
Scope: Rokinon 135mm at F/2.8
Camera: ZWO ASI533MC PRO (cooled at -10 °C)
Filters: Optolong L-Pro 2″
Mount: Celestron AVX
Guiding camera: ZWO ASI224MC, IR-Cut filter, PHD2
Guide Scope: Orion Deluxe Mini 50mm Guide Scope
Software: ASIAIR Plus, PixInsight, BlurXTerminator, NoiseXTerminator, GIMP
Total integration time: 60 minutes (30×120 secs.)
Calibration frames: 20 dark, 10 flat, 100 bias
M45 (2024-10-24)
M45 integration (2023-02-08)

Imaging the Pleiades from a light polluted sky

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Imaging the Pleiades from a light polluted sky

Less than 1 minute Reading time: Minutes

In the last few weeks I was actively chasing the green comet, but finally yesterday I decided to go back to something more traditional and I did some DSO imaging from my light polluted sky.

With Messier 45, the Pleiades, as my target, my goal was to capture the blue nebulosity that surrounds this magnificent star cluster.

My imaging setup was equipped with an Explore Scientific ED80CF APO 80mm triplet refractor and a cooled ZWO ASI533MC PRO OSC camera, making for a 60 minutes of total integration time. Despite the challenges posed by high clouds and the Moon, my trusty Optolong L-Pro light pollution filter did its job and delivered good results. Below you can see the detailed setup I used for this imaging session.

Date: 2023-02-08
Location: my driveway in Richmond Hill (ON)
Outside temperature: +1°C
Scope and camera: Explore Scientific ED80CF APO, ZWO ASI533MC PRO (cooled at -10 °C), Optolong L-Pro 2″
Focuser: ZWO EAF
Mount: Celestron AVX
Guiding: Orion Mini 50mm, ZWO ASI224MC, IR cut filter, PHD2
Software: NINA, PixInsight, NoiseXTerminator, BlurXTerminator, GIMP
Total integration time: 60 minutes (30×120 seconds)
Calibration frames: 20 dark, 10 flat, 100 bias
Size: 1.35 x 1.35 deg
Radius: 0.954 deg
Pixel scale: 4.05 arcsec/pixel

Here is the final image of the Pleiades, with its blue nebulosity that surrounds the cluster shining bright amidst the light pollution of the city.
 
Clear skies!
M45 integration (2023-02-08)
The Pleiades (2021-11-07)

The Pleiades with my APO refractor

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The Pleiades (Messier 45) with my APO refractor

Less than 1 minute Minutes
The Pleiades (Messier 45) captured with my backyard telescope. This open star cluster, located in Taurus, is made of hot blue and bright young stars and its distance is about 444 light-years.
According to the Greek mythology, the Pleiades were the seven daughters of the titan Atlas: Maia, Electra, Taygete, Alcyone, Celaeno, Sterope, and Merope. In Ancient Greece, the role of the Pleiades was that of companions and attendants to the goddess of the hunt, Artemis.
 
Date: 2021-11-07
Location: Richmond Hill (ON)
Scope: Explore Scientific ED80CF
Mount: Celestron CG-5
Camera: ASI533MC PRO (cooled at -10°C)
Focuser: ZWO EAF
Filter: Optolong L-eXtreme (narrowband filter)
Guide Scope: Orion 50mm mini + ASI224MC, PHD2
Software: NINA, PixInsight, GIMP
Total integration time: 15 minutes (5x180sec.), dark, flat, bias
 
 
Pleiades