ThatAstroChap Blog

Clear Night Is Now an App

Tue, 29 Sep 2026 00:00:00 GMT

You can now save Clear Night to your phone's home screen, where it opens as a stripped-back app with just the forecast.

Clear Night: An Astrophotography Forecast Tool

Fri, 19 Jun 2026 00:00:00 GMT

A new tool on the site that tells you whether tonight is worth setting up the telescope.

The Gallery and Blog Are Back

Sat, 13 Jun 2026 00:00:00 GMT

After a spell as a simple landing page, thatastrochap.com has a proper home again for images, write-ups and a handy forecast tool. Here's what's here, and what's coming.

Target Guide: The Pinwheel Galaxy (M101)

Sat, 12 Apr 2025 00:00:00 GMT

A face-on spiral nearly twice the size of the Milky Way, packed with star-forming regions that light up beautifully with a dash of hydrogen-alpha. How to frame, expose and process it.

Target Guide: The Leo Triplet (M65, M66 and NGC 3628)

Fri, 04 Apr 2025 00:00:00 GMT

Three interacting spiral galaxies in a single field of view, each showing the scars of their gravitational tug of war. The image I'm most proud of, and how to capture your own.

Target Guide: The Sunflower Galaxy (M63)

Tue, 25 Mar 2025 00:00:00 GMT

A flocculent spiral whose arms dissolve into thousands of short, fluffy segments, like petals on a sunflower. A rewarding galaxy season target for a small refractor.

ASIAIR Pro vs Plus: Is the Upgrade Worth It?

Sun, 12 Jan 2025 00:00:00 GMT

After years with the ASIAIR Pro I've upgraded to the ASIAIR Plus. Here's how the two compare, what convinced me to switch, and how I've set the new device up ready for its first clear night.

2024 Highlights: Nebulae, Galaxies and Big Upgrades

Tue, 31 Dec 2024 00:00:00 GMT

It's the last day of 2024, so it felt like the right moment to look back over a year of astrophotography: the switch to mono, a string of nebulae and galaxies, and a completely unexpected glimpse of the Northern Lights from southern England.

First Light Images in SHO with the ASI2600MM Pro

Sun, 18 Aug 2024 00:00:00 GMT

After a couple of quiet months I finally have my first two SHO narrowband images with the ASI2600MM Pro to share: the Elephant Trunk Nebula and the Cygnus Wall, captured over multiple nights from the back garden.

Target Guide: The North America Nebula and the Cygnus Wall (NGC 7000)

Thu, 01 Aug 2024 00:00:00 GMT

The North America Nebula is too big for most telescopes, and that's fine. The Cygnus Wall, its brightest ridge, is a superb narrowband subject in its own right.

Target Guide: The Elephant's Trunk Nebula (IC 1396)

Sun, 07 Jul 2024 00:00:00 GMT

A dark pillar of dust and gas winding through a vast emission region in Cepheus. My first narrowband target, and still one of my favourite recommendations for anyone starting out in SHO.

Making the Whirlpool Galaxy Pop: First Time Imaging in HaRGB

Fri, 14 Jun 2024 00:00:00 GMT

Galaxy season and a rare clear night gave me the chance to revisit the Whirlpool Galaxy (M51), this time in HaRGB with my new mono camera, the ASI 2600MM Pro.

Three Mistakes to Avoid When Installing a Filter Wheel

Thu, 16 May 2024 00:00:00 GMT

Installing unmounted filters into a filter wheel? Here are three mistakes I made first hand, and how to avoid dust, back-to-front filters and light leaks.

ASI 2600MM Pro First Light Review (With Antlia Filters and ZWO EFW)

Fri, 19 Apr 2024 00:00:00 GMT

After three years with a one-shot colour camera I've made the leap to mono with the ASI 2600MM Pro, Antlia filters and a ZWO filter wheel. Here's why I switched, how I tested for halos, and first light on Bode's Galaxy.

ASI 662MC: Finding Back Focus and First Light

Thu, 04 Apr 2024 00:00:00 GMT

After almost three months of waiting for a break in the clouds, I finally worked out the back focus on my refractor and captured first light on the Moon with the ASI 662MC.

Improve Your Guiding and Achieve Rounder Stars

Sun, 17 Mar 2024 00:00:00 GMT

Guiding has caused me more head scratching than almost anything else in this hobby. These are the five things that have made the biggest difference to my tracking error and the roundness of my stars.

StarNet2 vs StarXTerminator: Which Removes Stars Best in PixInsight?

Thu, 08 Feb 2024 00:00:00 GMT

I put StarNet2 and StarXTerminator head to head on a galaxy and a nebula, judging them on quality, speed, ease of use and price, to decide whether the paid option is worth my money.

Target Guide: The Horsehead Nebula (Barnard 33)

Tue, 30 Jan 2024 00:00:00 GMT

The most famous dark nebula in the sky, a horse's head of cold dust silhouetted against glowing hydrogen, with the Flame Nebula thrown in for free.

I Photographed the Horsehead Nebula with the William Optics ZS81 APO Telescope

Tue, 30 Jan 2024 00:00:00 GMT

A night spent photographing the famous Horsehead Nebula in Orion, framed alongside its neighbour the Flame Nebula and captured in three minute subs before the clouds had a chance to spoil things.

I Photographed the Orion Nebula with the William Optics ZS81 APO Telescope

Sun, 21 Jan 2024 00:00:00 GMT

Two nights spent capturing M42, the Orion Nebula, mixing sub exposures from one to three minutes to tame its huge dynamic range.

Target Guide: The Orion Nebula (M42)

Sun, 14 Jan 2024 00:00:00 GMT

The brightest nebula in the northern sky and the ultimate dynamic range challenge, where mixed exposure lengths make all the difference.

How to Install BlurXTerminator, NoiseXTerminator and Other RC Astro PixInsight Plugins

Fri, 05 Jan 2024 00:00:00 GMT

Getting the RC Astro plugins like BlurXTerminator and NoiseXTerminator working inside PixInsight, from adding the module repositories through to pairing each tool with its licence.

How to Install PixInsight on Mac

Tue, 02 Jan 2024 00:00:00 GMT

Installing PixInsight on a Mac is mostly painless, but there are a couple of moments where it pays to know what's coming, including one stage of the installer that looks completely frozen but isn't.

PixInsight in 60 Seconds: Four Tools I Use on Almost Every Image

Wed, 20 Dec 2023 00:00:00 GMT

Four PixInsight tools, four minute-long videos: DBE for gradients, SCNR for green casts, BlurXTerminator for detail and NoiseXTerminator for noise. The quick wins I reach for on nearly every image.

Target Guide: The Squid Nebula (OU4)

Fri, 17 Nov 2023 00:00:00 GMT

An extremely faint streak of ionised oxygen hiding inside the Flying Bat Nebula, and the hardest project I have attempted. Read this before you commit the hours.

I Launched a YouTube Channel

Thu, 09 Nov 2023 00:00:00 GMT

When I first decided to make an astrophotography website I did so with the primary goal of helping others. As a beginner I found the steep learning curve incredibly frustrating, daunting and diffic...

Quick and Easy Nebula Processing Using PixInsight

Tue, 31 Oct 2023 00:00:00 GMT

My quick and easy PixInsight nebula workflow, taking the Eastern Veil from a green-tinged stack to a finished image without getting lost in the weeds.

Target Guide: The Eastern Veil Nebula (NGC 6992)

Mon, 30 Oct 2023 00:00:00 GMT

The brighter half of the Veil. How to capture the eastern arc of the Cygnus Loop with a dual-band filter, and why old data is always worth a second look.

A PixInsight Workflow for Emission Nebulae

Mon, 23 Oct 2023 00:00:00 GMT

The start-to-finish PixInsight process behind the Bubble Nebula image, from WeightedBatchPreProcessing through background extraction, colour calibration and the final stretch.

Target Guide: The Bubble Nebula (NGC 7635)

Sun, 22 Oct 2023 00:00:00 GMT

A seven light year soap bubble blown by a single hot, massive star. Small, tricky and well worth the effort. How to frame, expose and process Cassiopeia's strangest object.

Rediscovering A Forgotton Nebula

Sat, 07 Oct 2023 00:00:00 GMT

Back at the beginning of 2023 when the days were short and the nights were long I embarked on a new project to photograph the Pacman nebula (NGC 281). Situated in the constellation of Cassiopeia ap...

A Brief Guide to Improve Guiding...

Sat, 16 Sep 2023 00:00:00 GMT

This post will be short and sweet, focusing on a couple of pointers I’ve found rather effective in improving guiding when using a ZWO ASI Air Pro (this model has been discontinued now but the advic...

The Iconic 'Pillars of Creation'

Tue, 22 Aug 2023 00:00:00 GMT

One of my favourite deep space photos was taken by Hubble in 1995. It features the “Pillars of Creation” situated at the heart of M16, the Eagle nebula. In 2014 NASA decided to point Hubble at the ...

Target Guide: The Eagle Nebula (M16)

Sat, 19 Aug 2023 00:00:00 GMT

Home of the Pillars of Creation. How to capture one of the most iconic star-forming regions in the sky, even from northern latitudes where it never climbs very high.

Target Guide: The Western Veil Nebula (NGC 6960)

Sat, 19 Aug 2023 00:00:00 GMT

Everything you need to know to capture the Witch's Broom, one of the most rewarding supernova remnants in the northern sky and a perfect dual-band filter target.

Astro 104: Focus

Wed, 09 Aug 2023 00:00:00 GMT

It's been a while since my last tutorial so let’s jump back in. This time I’m going to focus on focus.

Whale Watching

Sun, 04 Jun 2023 00:00:00 GMT

The U.K. has many bank holidays in the first half of the year and more often than not it feels like we end up with dreary weather on those specific days. Not this time though.

Target Guide: The Whale Galaxy (NGC 4631)

Fri, 26 May 2023 00:00:00 GMT

An edge-on spiral with real character, a dwarf companion on its back and the Hockey Stick next door. A fine spring galaxy project for a small refractor.

A Tryptic Failure

Thu, 27 Apr 2023 00:00:00 GMT

Back in December last year when it was cold (-6°C), clear and near perfect conditions for astrophotography. I decided to embark on a new project.

Target Guide: The Pacman Nebula (NGC 281)

Sat, 14 Jan 2023 00:00:00 GMT

Cassiopeia's hungry emission nebula. A circumpolar autumn target that responds well to dual-band filters, and proof that even a short, interrupted session can be worth keeping.

Lunar Photography Experimentation

Fri, 16 Dec 2022 00:00:00 GMT

Most of the time when I'm planning a night of imaging I default to looking for deep sky objects. These types of targets require dozens of long exposure subs which need stacking into a final image. ...

StarNet Installation on Mac

Mon, 12 Dec 2022 00:00:00 GMT

I recently decided to update the version of PixInsight I'm using and as such I ended up having to re-install the StarNet plugin. This can be a tricky process so I'm memorialising the approach to he...

Target Guide: The Andromeda Galaxy (M31)

Thu, 08 Dec 2022 00:00:00 GMT

The nearest major galaxy to our own, and one of the few deep-sky objects that's too big for the telescope. How to handle three degrees of galaxy from a back garden.

Astro 103: Polar Alignment

Sun, 20 Nov 2022 00:00:00 GMT

Time for another tutorial post! This time I'll cover polar alignment and talk through how I go about achieving it when setting up for a night if imaging.

Photographing NGC6888: Crescent Nebula

Fri, 11 Nov 2022 00:00:00 GMT

Since writing my last blog post, complaining about the lack of clear skies, I remembered that over the summer I tried to capitalize on the few hours of darkness available to attempt some astrophoto...

Astro 102: Balance

Wed, 19 Oct 2022 00:00:00 GMT

Over the last couple of months, the weather here has been pretty terrible, meaning I've not been able to get outdoors with my telescope for a long time. This leads me to writing another tutorial w...

Astro 101: Mounts

Fri, 23 Sep 2022 00:00:00 GMT

To start, it's worth clarifying what a “mount” is. Essentially, it's a tripod (or equivalent) that acts as a stable base for a telescope to sit atop. In general, the more stable the telescope is on...

Photographing M13: Hercules Globular Cluster

Thu, 28 Jul 2022 00:00:00 GMT

It had been a while since my last night of imaging; I reckon somewhere in the region of 3 months or more. As such I was keen to dust off my scope and get back outside again for another night of ast...

New Astro Gear

Sun, 17 Jul 2022 00:00:00 GMT

When I created this blog back in October of 2021, I did so with such good intentions of keeping it updated regularly but then life got in the way and here we are 9 months later...

Target Guide: The Crescent Nebula (NGC 6888)

Fri, 08 Jul 2022 00:00:00 GMT

A dying star's shell in the heart of Cygnus. Why this compact Wolf-Rayet bubble is one of the most rewarding summer narrowband targets from the UK.

Target Guide: The Hercules Globular Cluster (M13)

Thu, 07 Jul 2022 00:00:00 GMT

The finest globular cluster in the northern sky, and a rare target that wants short exposures. How to frame, expose and process M13 without blowing out its core.

Target Guide: The California Nebula (NGC 1499)

Tue, 01 Mar 2022 00:00:00 GMT

A two and a half degree ribbon of glowing hydrogen that's tailor-made for wide fields and small refractors, and a brilliant first nebula for autumn and winter evenings.

Target Guide: The Rosette Nebula (NGC 2237)

Thu, 13 Jan 2022 00:00:00 GMT

A vast stellar rose in Monoceros, bigger in the sky than the full Moon and glowing strongly in hydrogen-alpha. One of winter's most forgiving nebula targets.

Target Guide: The Pleiades (M45)

Wed, 05 Jan 2022 00:00:00 GMT

The Seven Sisters are the easiest deep-sky object to find and one of the trickiest to do justice. Why this is a dark-sky broadband target, and how to keep the dust wispy and the stars tight.

My Introduction To Astronomy

Fri, 01 Oct 2021 00:00:00 GMT

Ever since I was a young boy I've been obsessed with space and the night sky. I've always imagined what it must be like to experience walking on the moon, looking back at the tiny blue pearl that's...

Target Guide: The Pelican Nebula (IC 5070)

Sun, 18 Jul 2021 00:00:00 GMT

The North America Nebula's quieter neighbour rides almost overhead on UK summer nights. How to frame the Pelican, what the dark lane between them really is, and how I captured it.

Target Guide: The Whirlpool Galaxy (M51)

Sat, 24 Apr 2021 00:00:00 GMT

The classic grand-design spiral caught mid-collision with its companion, my favourite galaxy target and a rewarding test for a small refractor.

Target Guide: Bode's Galaxy (M81)

Sun, 04 Apr 2021 00:00:00 GMT

A bright, well-placed spiral that pairs beautifully with the Cigar Galaxy in one frame, and one of the best galaxy targets for a small refractor in the UK.