Yes. It is free and open source, under the GPL-3.0 licence, for Windows, macOS (Intel and Apple silicon) and Linux.

Is deconvolution in the stable release?

Not yet. The latest stable release, 3.0.2, has the background extraction and the AI denoising. Deconvolution came in the 3.1 prerelease builds (release candidate 1 in November 2024, release candidate 2 in January 2025); the deconvolution in my video is that beta.

Can GraXpert stack my images?

No. It works on an image that is already stacked, so stack your frames first in a program such as Siril or DeepSkyStacker.

Does it replace BlurXTerminator?

Not quite. Its deconvolution is not as powerful as BlurXTerminator, but it is still very capable of sharpening an image; BlurXTerminator works out the FWHM for you, where GraXpert asks you to enter it.

How long does it take?

On a 2 megapixel Seestar S30 image of the Orion Nebula the whole run, from the gradient to the denoiser, finished with the clock on screen at 23 seconds; a 60 megapixel image took under five minutes, and its denoising took twice as long as every other stage put together.

Which background method should I use?

The AI method needs no sample points and has one setting, smoothing; the other methods (RBF, splines and kriging) ask you to mark the background yourself.

What have I not tested on the GraXpert?

My walk-through ran on a JPEG copy of my finished North America Nebula, so it shows each tool at work rather than a raw stack processed from start to finish.

GraXpert review: free gradient removal in about two minutes

Where does it rank on our leaderboard

Nine of the 16 software on my board, against price
Rank	Software	Stars for Your Buck	Recorded UK price
1	Stellarium	100 out of 100	Free
2	NINA	98 out of 100	Free
3	SharpCap	97 out of 100	£14
4	GraXpert	96 out of 100	Free
9	ASIAIR app	89 out of 100	Free
10	Siril	88 out of 100	Free
13	RegiStax	77 out of 100	Free
15	DeepSkyStacker	71 out of 100	Free
16	Adobe Photoshop	67 out of 100	£22

Contents

01 Where does it rank on our leaderboard
02 Specifications and features
03 A walk through GraXpert
04 From the video
05 In my words
06 Watch it in my video
07 Should you buy it?
08 Questions and more about this review

In 30 seconds

Stars for Your Buck 96/100

Reviewed 17 Nov 2024 Updated 2 Oct 2026

Rank: #4 of 16 software
Verdict: Damon's pick

Written by Damon Scotting 3 min read

Buy it if

You image under light-polluted skies and your frames carry gradients.
You want a simple program: drop an image in and have a better one in minutes.
You want gradient removal and noise reduction without paying for them.

Open it, drop your image in, make a few changes, and in about two minutes you have a dramatically better picture.

GraXpert Free

Specifications and features

Against the software I have reviewed

Compare with

GraXpert reviewed #4 of 16	PixInsight #14 of 16	BlurXTerminator #5 of 16	NoiseXTerminator #8 of 16
Recorded UK price	Free	not recorded	£75	£45
Stars for Your Buck	96/100	76/100	95/100	92/100
Made by	The GraXpert Development Team	Pleiades Astrophoto (Spain)	RC Astro	RC Astro
What it is for	Removing gradients and denoising; deconvolution in the 3.1 prerelease only	Processing astrophotographs	Machine-learning deconvolution: sharpens stars and nonstellar detail separately and corrects coma, astigmatism, trefoil, defocus, chromatic aberration, motion blur from guiding errors and seeing variation	Machine-learning noise reduction for astrophotographs, with separate strengths for brightness and colour noise in fine and coarse detail
Licence	Free and open source (GPL-3.0)	€300 outside the EU; 45-day free trial	$100, permanent; free trial; bundle of three $190	$60, permanent; free trial; bundle of three $190
Operating systems	Windows, macOS (Intel and Apple silicon), Linux	Windows 11, macOS 26 and 15, Linux	Windows 10 (22H2) or later, macOS 14 or later, Linux	Windows 10 (22H2) or later, macOS 12 or later, Linux (PixInsight and the stand-alone tool)
Current version	3.0.2 stable; 3.1.0 release candidate 2 prerelease	1.9.4 Lockhart	2.6.9 (7 Sep 2026), RC Astro's unified tools	2.6.9 (7 Sep 2026), RC Astro's unified tools

A walk through GraXpert

Background extraction My North America Nebula loaded, with AI chosen as the background extraction method. It needs no sample points; its one setting is smoothing.

Gradient corrected After Calculate Background the view switches to Gradient-Corrected: the same frame with the background model taken out.

The background model The Background view shows what GraXpert removed: a smooth map of the glow it found across the frame.

Denoising The Denoising step has one slider, Denoise Strength, and a Denoise Image button. In the stable release it comes straight after the background extraction.

From the video

GraXpert in my video

My Seestar S30 North America Nebula before the gradient removal

The same frame after the AI background extraction

Deconvolution in the 3.1 beta, on my Seestar S30 Horsehead Nebula

The Horsehead after the denoiser at full strength

In my words

“GraXpert was already a tool I rated very highly, because the difference it makes to images from light-polluted skies like mine is incredible. Then a couple of years ago it added deconvolution and noise reduction too, in the same simple way. I cannot speak highly enough of how easy it is. Everything is laid out clearly, there are advanced settings if you want to fine-tune, but mostly you open it, drop your image in, make a few changes and within about two minutes you have a dramatically better picture. It feels like the kind of tool they could charge for, and they don't. That is why it gets 96.”

From my dictated take

Watch it in my video

How to HUGLEY IMPROVE your Astro images in under 2-Minutes! (Seestar S30 /GraXpert / Telescope Live) · published 17 November 2024 · 9:28 · Watch on YouTube · 67,911 views, 1,833 likes on 2 Oct 2026

Jump to

0:28 Removing gradients in GraXpert
1:43 The AI background extraction
2:41 The deconvolution beta
3:59 The denoiser
4:46 Start to finish against the clock

Transcript of the video 915 words · 6 chapters · searchable

Press a time stamp to play from there.

0:28 Removing gradients in GraXpert

0:29 telescope live so there will be a variance in image data GraXpert was initially designed as a tool to remove gradients from your astro images 0:34 which is a very common occurrence perhaps a Target your Imaging is quite low in the Horizon and you live near very light polluted areas maybe there's 0:41 a bright moon out and your target is fairly nearby or maybe you just haven't corrected the tilt shift on your camera the effect this can have on your images 0:48 is devastating so how can we fix it simple download the software open it up and load your chosen image it's likely that you're going to see basically 0:57 nothing so make sure you enable at least a 10% image stretch at the bottom of your screen ta-da now especially when it comes to images captured with a Seestar you're 1:05 going to want to crop the edges ever so slightly just to get rid of these awful looking noisy patterns on the outer edges then open up the background 1:12 extraction tab which by the way is pretty much all this software used to be as a feature plain and straightforward until now when they've just taken it to 1:20 the next level with all of these extra features you'll be presented with four different methods for removing your unwanted image gradient normally you'd have to select the areas that represent

1:20 The four background methods

1:28 the general image pattern this is is to say not the Deep Sky object you're Imaging you're trying to outline what this image gradient looks like so if you 1:36 highlight for example in this image the nebula then it's going to try and compensate for those varying colours but this is part of the reason as to why

1:43 The AI background extraction

1:43 this entire process can now take under 2 minutes because the latest option is AI and it requires no further input no display points to be added no list of 1:52 Sliders to be adjusted bar one and it completes almost immediately so look at that already our image has drastically improved but in doing so I can't help 2:01 but feel like we've lost a little bit of texture and depth in our image which is very unfortunate so in order to avoid that I'm going to drag this smoothing 2:08 slider all the way to one now that's much better a key thing to note is that astrophotography is an art form the beauty of your images is going to be 2:15 subjective the important part is to stylize your images how you enjoy them best if someone else doesn't like them then boohoo good for them or whatever 2:23 you're always going to get comments saying you've oversaturated this or you've oversharpened that the colours are all wrong blah blah blah blah ignore them it's all subjective and if you need 2:33 a definitive proof of that then look no further than narrow band Imaging there's seemingly no right way to process your images this is GraXpert's latest

2:41 The deconvolution beta

2:41 development their deconvolution tool currently only accessible by downloading their beta don't worry I've attached the link in the description below just download whichever one corresponds to 2:50 your operating system and then reboot GraXpert you'll know it works when you're greeted with this message now deconvolution is an unbelievably helpful method that helps remove the blur or 3:00 Distortion in your images caused by atmospheric disturbance or your own Optics the most powerful demonstration of this tool is currently Russell Croman's BlurXTerminator available for just 3:09 under $100 is a feature I've used a lot when editing in PixInsight this is how my image of Andromeda looked before I used BlurX versus after it's so good it 3:19 can almost be referred to as a cheat code that's how stark the difference is between using it and not well the new GraXpert deconvolution tool isn't as

3:22 GraXpert against BlurXTerminator

3:27 powerful but it's still very capable of sharpening your images with the $100 BlurX tool it determines your FWHM for you but GraXpert asks you to input this 3:35 information yourself the FWHM refers to the full width half maximum and you can find this out even through the use of other free software such as Siril but 3:43 with the context of speed in mind I'm going to ignore finding specifics because even with the knowledge of what your images FWHM is it doesn't guarantee 3:51 an image adjustment you're going to like so instead just have fun play with the slider find something for you that sticks then when you're done move on to

3:59 The denoiser

4:00 the final layer of this phenomenal Astro editing cake the denoiser now Seestar images are particularly noisy they are doing the absolute best with what 4:09 they've got the images I've captured so far were done during a full moon with lots of thin clouds passing by so just to show off the full power of this tool 4:16 I'm going to crank it all the way up to its Max setting one look at that it's like night and day again play with this 4:24 until you find a setting you personally like if you use the max setting sure your image is going to look smooth but it will feel like you've lost a lot of 4:31 the sharpness and structure throughout the image personally I always find a bit of noise good it makes the image feel more real I actually prefer doing 4:38 background extraction denoising saving the image and then playing with the deconvolution settings but each to their own right now that we've covered the

Should you buy it?

96/100 Stars for Your Buck

Pros

The difference it makes to images from light-polluted skies is incredible.
Noise reduction sits beside the gradient removal in the same simple way, with deconvolution in the 3.1 prerelease.
Everything is laid out clearly, with advanced settings if you want to fine-tune.
It is free.

It feels like the kind of tool they could charge for, and they don't.

Three alternatives I have reviewed

Questions and more about this review

Reviewed by

Damon Scotting

The Telescope Man Verified

BSc (Hons) Physics with Astrophysics and Cosmology, Loughborough University PGCE / QTS, University of Nottingham

About Damon About Damon Damon Scotting is The Telescope Man. He holds a BSc (Hons) in Physics with Astrophysics and Cosmology from Loughborough University and a PGCE with QTS from the University of Nottingham, and taught physics in secondary schools before becoming an astronomy creator. He is a contributing writer for BBC Sky at Night Magazine and the author of 42 Wonders of Our Night Sky, and his photograph of the galaxy M100 with the dwarf planet Ceres was Highly Commended in the Astronomy Photographer of the Year 2024 competition run by Royal Observatory Greenwich. He has appeared on the BBC's Blue Peter. More than 750,000 people follow his astronomy channels on YouTube, Instagram and TikTok, and he has reviewed more than 140 telescopes, mounts, cameras, filters and accessories hands-on for this site. More about Damon · How I test · Damon's book

I review all kinds of gear: most of it I buy, some is gifted and some is loaned, and all of it is reviewed the same way. How this site is funded

Seven questions, answered

Questions about the GraXpert

Reviewed 17 November 2024 ·Updated 2 October 2026

I review all kinds of gear. Most of it I buy, some is gifted and some is loaned, and all of it is reviewed the same way: no company sees or approves a review before it is published. How this site is funded

Is GraXpert free? Yes. It is free and open source, under the GPL-3.0 licence, for Windows, macOS (Intel and Apple silicon) and Linux. The specifications and the comparison table ↓
Is deconvolution in the stable release? Not yet. The latest stable release, 3.0.2, has the background extraction and the AI denoising. Deconvolution came in the 3.1 prerelease builds (release candidate 1 in November 2024, release candidate 2 in January 2025); the deconvolution in my video is that beta. Watch it in my video ↓
Can GraXpert stack my images? No. It works on an image that is already stacked, so stack your frames first in a program such as Siril or DeepSkyStacker. From my video review The specifications and the comparison table ↓
Does it replace BlurXTerminator? Not quite. Its deconvolution is not as powerful as BlurXTerminator, but it is still very capable of sharpening an image; BlurXTerminator works out the FWHM for you, where GraXpert asks you to enter it. From my video review Watch it in my video ↓
How long does it take? On a 2 megapixel Seestar S30 image of the Orion Nebula the whole run, from the gradient to the denoiser, finished with the clock on screen at 23 seconds; a 60 megapixel image took under five minutes, and its denoising took twice as long as every other stage put together. From my video review Watch it in my video ↓
Which background method should I use? The AI method needs no sample points and has one setting, smoothing; the other methods (RBF, splines and kriging) ask you to mark the background yourself. A walk through GraXpert ↓
What have I not tested on the GraXpert? My walk-through ran on a JPEG copy of my finished North America Nebula, so it shows each tool at work rather than a raw stack processed from start to finish.