As a small sensor user (585) I depend on sharpening to create images that look good full screen. The question is, how much is too much. In lunar/planetary work, sharpening is a basic and required part of the work flow. Deep sky images also suffer from a certain amount of degradation, mostly because of seeing and slightly from stacking so it seems reasonable to recover the resolution lost as most of us do. The question is, what kind of a standard do you apply in terms of what is reasonable and what isn’t.
How much sharpening is too much?
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If you can see it then it's too much.
andrea tasselli · Nov 6, 2025, 08:12 PM
If you can see it then it's too much.
That’s a good guideline. Over sharpening is the easiest way to make a good picture bad, and a bad picture into a mess.
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Generally speaking, with BlurX if you see bright edges on your nebulae, you’ve gone too far.
As for stars, I rarely use more than 0.05 power or just correct only in BlurX.
Hopefully this screenshot describes what I’m getting at. It’s kinda like ‘ringing’ in lunar images.
📷 image.png
When in doubt, use as little as possible. You can’t magically overcome bad seeing with BlurX….but there are ways to massage the detail out still. Theres no perfect number to give out because BlurX is dynamic based on PSF.
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I use Lightroom to apply a bit of texture but I use a mask to selectively apply it. I adjust it until I see the effect and then back it off a bit to prevent any noise.
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
Tony Gondola · Nov 6, 2025 at 08:43 PM
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
Tony,
I use BlurXT all the time. You can use the real time preview to fine tune how much or how little sharpening you can apply. All stars need some sort of correction at a minimum. You do need Pixinsight to use it as it will not run on Siril.
Dave Stearn · Nov 6, 2025, 08:56 PM
Tony Gondola · Nov 6, 2025 at 08:43 PM
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
Tony,
I use BlurXT all the time. You can use the real time preview to fine tune how much or how little sharpening you can apply. All stars need some sort of correction at a minimum. You do need Pixinsight to use it as it will not run on Siril.
So then the question becomes, is BlurX the only tool that can give all the advantages without most of the pitfalls as outlined above. To that list I would add halos, panda eyes and crispy random artifacts.
Tony Gondola · Nov 6, 2025 at 09:16 PM
Dave Stearn · Nov 6, 2025, 08:56 PM
Tony Gondola · Nov 6, 2025 at 08:43 PM
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
Tony,
I use BlurXT all the time. You can use the real time preview to fine tune how much or how little sharpening you can apply. All stars need some sort of correction at a minimum. You do need Pixinsight to use it as it will not run on Siril.
So then the question becomes, is BlurX the only tool that can give all the advantages without most of the pitfalls as outlined above. To that list I would add halos, panda eyes and crispy random artifacts.
BlurX is the best tool out there and it does have. Setting for halos. There are plenty of YT videos that show how it works.
Tony Gondola · Nov 6, 2025, 09:16 PM
Dave Stearn · Nov 6, 2025, 08:56 PM
Tony Gondola · Nov 6, 2025 at 08:43 PM
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
Tony,
I use BlurXT all the time. You can use the real time preview to fine tune how much or how little sharpening you can apply. All stars need some sort of correction at a minimum. You do need Pixinsight to use it as it will not run on Siril.
So then the question becomes, is BlurX the only tool that can give all the advantages without most of the pitfalls as outlined above. To that list I would add halos, panda eyes and crispy random artifacts.
Manual deconvolution is a lost art by now. Some of us might still know how to do it, but even the best trained at it are not going to come close to the results that BlurX can produce. It’s become the gold standard.
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First of all, BXT is great. It simplifies deconvolution.
However, you can still achieve great results by applying good old school deconvolution as well. I did a quick comparison a year ago, check out this thread. This was BXT vs the standard deconvolution settings in Pixinsight. And it comes pretty darn close without adjusting anything at all. Deconvolution is available in Siril as well.
Again, BXT is great. It makes it easier for most people to get a better image. But it’s not that groundbreaking when compared to the deconvolution process.
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Standard deconvolution does not correct for field aberrations and although BXT does NOT correct all of them to the full (and leaves "residues") it does it a lot better than standard LR deconvolution. In truth I expect that in reality BXT just gets away with it by "rounding" the PSF rather than modelling all the vagaries of field aberrations for the various systems out there. This said "sharpening" can be achieved more economically by other tools if that is what you're after.
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It’s possible to remove most field aberrations (coma, guiding) by creating a synthetic star field and blending that as a luminance layer with the original star field. It can be done, it just involves more steps.
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In my experience BXT can only do so much with it anyways. If you put a bad image through it, the result will be subpar too. At least as far as my own tests go. Normally I see little to no difference when used on good enough data.
Anyhow I think deconvolution, wavelets, unsharp mask etc are good tools to use. My main point was that I don’t think anyone has to use BXT. It’s just easier for the masses to use a “plug n’play” process.
Tony Gondola · Nov 6, 2025 at 08:43 PM
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
You can apply different BlurX settings to the stars and the non-stellar objects. Or process star and starless images separately.
Tony Gondola · Nov 6, 2025, 09:16 PM
Dave Stearn · Nov 6, 2025, 08:56 PM
Tony Gondola · Nov 6, 2025 at 08:43 PM
Relative to stars it seems like all sharpening processes degrade that beautiful gaussian profile that all unmolested stars have. A somewhat soft looking ball with edge nice fall off is the ideal, I don’t have access to blurX so maybe it doesn’t change that profile but every other process I’ve tried does. It seems that even the most gentle of approaches will harden the star edges to some degree.
Tony,
I use BlurXT all the time. You can use the real time preview to fine tune how much or how little sharpening you can apply. All stars need some sort of correction at a minimum. You do need Pixinsight to use it as it will not run on Siril.
So then the question becomes, is BlurX the only tool that can give all the advantages without most of the pitfalls as outlined above. To that list I would add halos, panda eyes and crispy random artifacts.
I think SetiAstro Suite now has Cosmic Clarity, which is intended to be similar to BxT. It's free and you could try that as well. Franklin Marek has put out a bunch of videos on how to use SaS and all of its various tools.
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That’s what I use most of the time. The sharpening it provides is excellent but I don’t care for the noise reduction part. In fact, I’ve noticed that most non-Bx reduction options suffer from the same issue and that’s preserving detail in low SNR areas. They do great where there’s a lot of signal and detail but tend to turn low signal/contrast areas into an overly smooth cloudy mush.
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